GISP Exam Prep
NAPP
(National Aerial Photography Program) A USGS program that provides aerial photographs, taken between 1987 and 2004, over the contenninous United States.
How is the board of directors of GISCI made up?
-10 people total-Two people from each contributing organization
What is an API?
-Application Programming Interface - data is accessed and exchanged as needed between software systems
What disciplines are associated with Geomatics?
-Cartography -Earth mapping -Geography -Geophysics -GPS -Land surveying -Photogrammetry -Remote Sensing
If developing standards were a symphony, what would be ISO's role?
-Conductor-the orchestra is made up of independent technical experts nominated by members.
Nominal Data
-Data of categories only. -Data cannot be arranged in an ordering scheme. (Gender, Race, Religion)
What are the common kinds of GIS platforms?
-Desktop -Enterprise GIS -Hosted (cloud) -Server
What is the difference between a DISCRETE RASTER and a CONTINUOUS RASTER?
-Discrete rasters: categorical and have distinct values identifying each cell (e.g. land use) -Continuous rasters: are grid cells with gradual changing data such as elevation, temperature or an aerial photograph.
What are some general rules for drone flying?
-Fly within line of sight -Flown during daylight of civil twilight -Flown at no more than 100mph -Cannot fly directly over people -Cannot fly from a moving vehicle in a populated area -Yield to other aircraft
What is PostGIS?
-Open-source software program -Adds support for geographic objects to the PostgreSQL object-relational database.
1 ft = meters?
.3048
How many kilometers are in a mile?
.62
What files are required for a shapefile to work?
.shp .dbf .shx
ASCII files are often delivered in what formats?
.txt .dat .csv
What is the accuracy of a mapping grade gps?
0.5-2 meter and 3-5 meter
What does a Kappa coefficient of 1.0 mean? What about 0?
1 means the data is fully in agreement, 0 means the agreement is no better than random chance. A coefficient of .4 or below usually means that there is no correlation between data (presence of a septic tank and increased nitrogen in stream, for example)
1/60th of a degree is ________________?
1 minute
What is the required accuracy of a state plane coordinate system?
1 part in 10,000 or less. State may have 2 or more SPC zones
1/60th of a minute is _________________?
1 second
What values are NDVI data collected in? What does each end of the spectrum mean?
1 to -1 1 means growing vegetation, -1 means water or rocks
SDTS Standards
1. Accuracy testing performed against independent source of higher accuracy 2. Compare identifiable locations on the raster to known ground locations, compute RMSE 3. Raster accuracy should be reported at 95% confidence 4. A minimum of 20 check points should be tested (only <1 can fail for 95% confidence)
Name the three most commonly used spheroids
1. Clarke 1866 2. GRS_1980 3. WGS_1984 (more precise GRS_1980)
Imprecision: Name 5 issues that cause error in data
1. Data collection device limitations 2. Data collection errors 3. Data entry errors 4. Data storage limitations 5. Data storage mistakes
Name the four types of tectonic plates boundaries.
1. Divergent (ocean ridge spreading) 2. Convergent 3. Transform boundaries 4. Subduction zone
Data exchange methods (4)
1. Export to exchange format or compress a .gdb (zip or tar file) 2. Put on FTP site, Web Portal, or Disk for sharing 3. Data exchange between software 4. Web service data exchange: user/consumer; no data is downloaded
FGDC endorsed metadata standards?
1. FGDC CSDGM 2. ISO 19115 Original ISO 3. ISO 19115 NAP North American Profile 4. ISO 19139 XML schema implementation ISO 19115 is a content standard that defines what information should exist in a metadata document ISO 19139 produces an XML Schema defining how metadata conforming to ISO 19115 should be stored in XML format
What format are USGS Topo maps available in?
1. Geotiff 2. JPEG 3. KMZ
When do you use geodesic measurements?
1. In an unprojected map 2. For a very large distance where the curvature of the Earth may impact figures; couple hundred+ miles
What two references frames are currently used globally?
1. International Terrestrial Reference Frame (ITRF) 2. WGS84 Reference Frame 10mm difference between the two
Name four common projections
1. Mercator 2. Lambert 3. Albers 4. Robinson
What are the two principle vertical datums in use?
1. North American Vertical Datum of 1988 (NAVD88) 2. National Geodetic Vertical Datum of 1929 (NGVD 29)
Name 4 open source relational databases
1. PostGreSQL 2. MySQL 3. MondoDB 4. SQLLite
What are 4 ways to check the accuracy of a raster?
1. Spectral: cell values proper values (elev or color)? 2. Temporal: raster accurately reflect time period 3. Spatial: proper location? 4. Radiometric: features distinguishable?
How would you convert 45°.41 from DD to DMS? REVIEW
1. Take 45 and keep it 2. Take .41 and multiply it by 60 (there are 60 minutes in a degree). That equals 24.6. You keep 24. You now have 45°24" 3. Take .6 and multiply it by 60 (there are 60 seconds in a minute). That equals 36. 4. The answer: 45° 24" 36'
How would you convert 25° 15" 30' to decimal degrees? REVIEW
1. Take the 25 and keep it 2. 15' is 15 minutes out of 60. So 15/60 = .25 3. Divide 30/3600 (60 seconds in a minute, 60 minutes in a degree = 60x60=3600) 4. 25 + .25 + .0083333 = 25.2583333 The answer: 25.2583333
Each SPC is mapped onto which two map projections?
1. Transverse Mercator - zones elongated North-South 2. Lambert Conformal Conic - zones elongated East-West
What are the 4 variants of the Mercator projection?
1. Web Mercator 2. Transverse Mercator 3. Universal Transverse Mercator (UTM) 4. Oblique
What type of field would you use for: 1. Latitude and Longitude 2. The number 150,000.45 3. The number $500.00 4. Microsoft Word file
1. double 2. double 3. float (can only store 6 digits) 4. BLOB
What is the required horizontal accuracy of 1) A map larger than 1:20,000 and B) A map 1:20,000 or smaller?
1/30 (.033) and 1/50 (.02)
Which is a better SNR? 1000/500 or 1000/20?
1000/20. It is Signal Strength/Noise Level so higher SNR values are better (more signal strength to noise).
An elevation raster must be at least _____ bits, usually.
16 bits
What year were USGS Topo maps first published? What scale (typically)?
1884; 1:24,000 (7.5min x 7.5min)
What is the range of the following dataset? 10,10,10,10,10,10,80,80,80,80,200,200,200
190
Which is the small scale map, 1:100 or 1:250000?
1:250000 One inch on the map represents 250000 inches in real life vs one inch representing 100 inches in real life
What is the difference between NAD83 and WGS84 in meters?
1m or less in continental USA
What is the accuracy of a military grade GPS?
1mm to 1 meter
How many check points are necessary according to the SDTS?
20
What is the minimum amount of points to check for each dataset, according to the FGDC?
20 check points must be compared to a high accuracy data source
What is this angle in South Azimuth? How do you measure it?
225 Clockwise from South
How much wider is the Earth at the equator?
27 miles
What is a planar measurement? What is the only type of map it can be used on?
2D measurement (Pythagorean) Can only be used on a projected map
What type of georeferencing uses 6 links? What type of transformation is it?
2nd Order. It is a polynomial transformation.
Radian Measures: 360 degrees = ?
2πrad
1 meter = feet?
3.28
What is the accuracy of a consumer/recreational grade GPS device?
30 meters
How many degrees are there are Earth (in reference to DMS)?
360
What type of georeferencing uses 10 links? What type of transformation is it?
3rd Order. It is a polynomial transformation.
How many satellites are required to calculate a GPS position?
4
What is the median of 1,2,3,4,5,6,7,8?
4.5 Because it's an even number of values in the dataset, 4 and 5 are averaged and that is the median.
πrad/4 = degrees?
45 Because πrad = 180, 180 / 4 = 45
What is this angle in North Azimuth? How do you measure it?
45 Clockwise from North
If North is 0, what would a 45 degree angle to the east be in Polar? How do you measure it?
45 Clockwise from due east
What is integer division?
5/2 = 2 (there is no remainder in integer division)
How many feet are in a mile?
5280
How much can drones weigh?
55 lbs
What is the scale of 123.123456?
6 (6 spaces after the decimal point)
How wide is a UTM zone? How many zones are on the Earth?
6 degrees 60 zones (60x6=360 degrees)
1 degree is how many minutes
60 minutes
How many significant digits can a float value hold?
7 significant digits
What is the Precision of 123.123456?
9 (can store 9 total digits)
What percentage of points on a map have to match the horizontal accuracy to pass the NMAS standard?
90% for both smaller or larger than 1:20,000
What percentage of accuracy is necessary for rasters to pass the SDTS standard?
95%
What does HSV stand for?
hue - base color saturation - lightness or darkness of color value - intensity of color
What is MAUP?
modifiable areal unit problem
Name the 3 types of faults?
normal fault (together), reverse fault (together), strike-slip (side by side) fault
What is the difference between a centroid, an area, and a perimeter?
A centroid is the "central" location of the polygon The area is the LxW of the polygon The perimeter is the total measure of the length of the outside of the polygon
What is a .e00 file format?
A compressed coverage (this was an incorrect answer on the test but be aware of what the file type is)
What is a coverage? How is it different from a feature class or shapefile?
A coverage is a historical dataset that is not used anymore and was replaced by the feature class. Coverages were a topological dataset that contained points, lines, polygons, regions, routes, and sections
What is a curve? How is a true curve defined?
A curve is defined by vertices A true curve is defined and stored as an equation
What is a relational database?
A data structure where collections of tables are associated by a common "key" field
What is a datum?
A datum is a mathematical model based on a spheroid that also includes X, Y, Z shift by fitting control points in equation.
What is a Key Field / Primary Key?
A field that is shared across multiple datasets in a relational database
What is the difference between a geographic coordinate system and a projected coordinate system?
A geographic coordinate system (GCS) is a reference framework that defines the locations of features on a model of the earth. It's shaped like a globe—spherical. Its units are angular, usually degrees. A projected coordinate system (PCS) is flat. It contains a GCS, but it converts that GCS into a flat surface, using math (the projection algorithm) and other parameters. Its units are linear, most commonly in meters.
What is a .gpkg? What is it based on? Can it store both vector & raster data?
A geopackage Universal file format for geodata based on SQLLite. Yes, it supports both.
What is a Planimetric Map?
A map that does not include relief (elevation) data
What is a thematic map?
A map that has been symbolized on attributes
What is a planimetric map?
A map that has no relief data For example, a map that only shows roads buildings, rivers and lakes but no elevation data
What is standard deviation? How is it calculated?
A measure of how spread out the data is. Calculated as the root square of the variance.
What is a loxodromic measure?
A method of navigation by following a rhumb line, a curve on the surface of the Earth that follows the same angle at the intersection with each meridian. This serves to maintain a steady course in sailing.
What is a relationship class?
A permanent connection between items in a geodatabase
What is a planar measurement?
A planar measurement is something measured in 2D space
How would you describe a planimetric map?
A planimetric (plan) view, by contrast, looks as though every position on the ground is being viewed from directly above.
What is a binary raster?
A raster that has been classificed into 2 classes (1, 0 or "true or false")
How do you define a polygon?
A set of vertices that begin and end on the same point
Ordinal data
A statistical data type that exists on an arbitrary numerical scale where the exact numerical value has no significance other than to rank a set of data points. Deals with the order or position of items such as words, letters, symbols or numbers arranged in a hierarchical order. Quantitative assessment cannot be made.
When selecting by location, what does "touch the boundary of" select?
A target feature will be returned by this function if the intersection of its geometry with the geometry of the source feature is nonempty, but the intersection of their interiors is empty. This is the definition of the Clementini touch operator, so if the target feature touches (as defined by Clementini) the source feature, it will be returned by this function
When selecting by location, what does "have their centroid within" select?
A target feature will be selected by this operator if the centroid of its geometry falls into the geometry of the source feature
What is a voroni diagram?
A voroni diagram is a visual represenatation of thiessen polygons
How do you find Euclidean Distance?
A(squared) + B(squared) = C(squared) Add the square of A & B, take the square root of that number. The PT is used for determining distance along a route.
What five organizations are members of the GISCI?
AAG GITA NSGIC UCGIS URISA
In a Venn Diagram of two circles, if the middle part is shaded, that represents what function?
AND
Does water absorb or reflect infrared light? What color will it usually show up as in composite imagery?
Absorbs, it shows up as bright red on composite imagery
What level of accuracy is needed for any given project?
Accuracy and precision depend on the business needs of the client
What is an example of a local operation?
Adding two rasters together Conversion of units
What are some standards that the FGDC publishes?
Addressing, metadata and content standards, geographic information data quality, soil code standards, classification of wetlands, National Standard for Spatial Data Accuracy
Definte the affine transformation type of georeferencing.
Adds the ability to "skew" the image as well as scale, rotate, and translate from the similarity transformation.
What is the APFO?
Aerial Photography Field Office (division of USDA)
What cartesian coordinate system is best for preserving area?
Albers Equal Area
What is georeferencing?
Aligning unreferenced data to a dataset that is spatially referenced
What is an edge?
Alternate name for a node (review definition)
What is an Esri GRID file?
An Esri grid is a raster GIS file format developed by Esri, which has two formats: A proprietary binary format, also known as an ARC/INFO GRID, ARC GRID and many other variations A non-proprietary ASCII format, also known as an ARC/INFO ASCII GRID
What does a geodatabase model everything as?
An object
How do you define a line?
An ordered set of vertices
What is a cartesian coordinate system?
Another name for a Projected Coordinate System
When selecting by location, what does "intersect" select?
Any feature that intersects the source layer The Mississippi watershed intersects many states
What would this query select? StreetName = "Olive" AND (SpeedLimit = 0 OR SpeedLimit = 55)
Any segment of Olive that has a speed limit of 0 or 55
The following would result in what? Con("Area Solar Rad" > (75000 + 3*4900.093), 1)
Any value that's more than (75000 + 3*4900.093) would be exported as a 1. This would be a binary raster and only export the values that meet the criteria. No other values would be exported.
What would this select? StreetName like "%Olive%"
Anything that has "olive" in the name. Soliver Street, Soliverias Street, Olive Street, for example.
What would this select? StreetName like "Olive%"?
Anything that starts with OLIVE
What is the difference between append and merge?
Append "adds" data to an existing feature class, merge combines two feature classes and creates a seperate output
What is a spheroid or ellipsoid?
Approximation of the shape of the Earth. It is based on a mathematical equation the mimics Earth's shape
What is the difference between archiving and backups?
Archiving is to provide access to older files (delivered final file geodatabase to a client, it's been archived) Backups are short term storage to protect data that changes on a regular basis (backing up stormwater feature classes)
What is a vertex?
one point from a set of ordered points that defines the shape of a polygon or line
What is thematic accuracy?
Are the attributes associated with the location correct? (Is it a 4 lane street, or a 2 way street? The data may be geometrically accurate but not thematically accurate and vice versa)
What is meant by temporal accuracy in raster data?
Are the cell values correct for conditions during the time period it was gathered?
What is meant by spatial accuracy in raster data?
Are the cell values in the right place? Does the cell size accurately represent the area modeled?
What is meant by spectral accuracy in raster data?
Are the cell values the proper elevation or color
What is meant by radiometric accuracy in raster data?
Are various features able to be picked out from each other? Greater bit depth = higher resolution
What are the four kinds of distortion introduced by cartesian (projected) coordinate systems?
Area, Shape, Distance, Direction
If an image file doesn't store georeferencing information in the header, how is it usually stored?
As a seperate ASCII file
What are lines where the shape of the surface abruptly changes(e.g. ridge-lines, streams, or roads) called in TINs?
As breaklines
What is the alpha data type in a raster for?
Assigns a transparency pixel by pixel
How does the "majority" technique resample a raster?
Assigns the most popular value from surrounding 4 cells
What is the vertical accuracy and percentage of points to pass a NMAS standard?
At least 1/2 the contour interval, 90% (again)
What order should these GPS types be in, from most to least accurate? Mapping Grade, Survey Grade, Aviation & Military, Recreational
Aviation & Military, Survey, Mapping, Recreation
Generally, which projection would be best to map polar regions? What are two names for this type of projection?
Azimuthal Azimuthal, Planar
BREAK
BREAK
Geodatabase versioning is a type of ___________?
Backup
If you print a map and are unsure if it will be resized, what type of scale should you use?
Bar Scale The bar scale will always be proportional to the whatever size it is changed to
DEMs represent _________________ elevations?
Bare Earth
What is a BLOB field type? What can it store?
Binary Large Object Blob fields can hold entire files in a single cell. Shape in ArcGIS is an example of a Blob field (it says "polyline" but actually refers to multiple x,y,z points)
Overlay analysis is based on ________________?
Boolian Logic
If two maps are 1:100000 and one is printed on larger paper, which is the smaller scale map?
Both are the same. Scale matters, page size does not.
What is the structure of a CAD file?
CAD files are layers of points, lines and polygons and may also be rasters and can be projected
What does CDMA stand for? What does it do and why is it necessary?
CDMA stands for Code Division Multiple Access. All satellites transmit signals at same frequency. It keeps signals separated into channels.
CHAPTER 3: Mapping the Globe
CHAPTER 3: Mapping the Globe
CHAPTER 4 ESSENTIAL GEOMORPHOLOGY TERMS
CHAPTER 4 ESSENTIAL GEOMORPHOLOGY TERMS
CHAPTER 6 GIS FILE TYPES
CHAPTER 6 GIS FILE TYPES
What is an example of a focal operation?
Calculating values around a defined pixel or area. Consider a "window" and then what surrounds it. "What kind of land uses are in this 1 mi X 1 mi area?
Where is the international date line?
opposite side of prime meridian (180 degrees longitude)
When performing an overlay raster analysis, what has to match?
Cell sizes You will need to choose whether to resample the smaller resolution to large resolution, or large resolution to small depending on the application
What does the con prefix mean in the raster calculator?
Conditional statement (if, then, else)
What are the four classes of map projections?
Conformal, Equivalent, Equidistant, Azimuthal
What are global operations in Map Algebra?
Considers the whole map and exports a number. For instance, what is the average precipitation value of the entire raster?
What are the 3 grades of GPS devices?
Consumer/Recreational, Mapping Grade, Survey and Military Grade
What is the CSDGM?
Content Standard for Digital Geospatial Metadata It is developed by the FGDC and does not tell exactly how metadata should be stored but rather what should be in it
What is CORS? What is it for?
Continuous Operating Reference Station. Run by NOAA, it is a network of permanent stations that are used to post process GPS data.
Lines of equal value: A map showing elevation or depth?
Contour line
What cartographic elements are optional on a map?
Coordinate System, Author Name, Organization, Graticules, North Arrows
What is COGO? Why is it used?
Coordinate geometry. It is used to draw points lines and polygons using survey points and measurements
How do you define a point?
Coordinate pairs X, Y, sometimes Z values
When selecting by location, what does "are within a distance of" select?
Creates buffers around source layer and selects features within those areas Seattle is within 20 miles of Bellevue
What is extrusion?
Creating 3D data out of non-3D data (contour lines, for example)
Name 3 methods to measure lat/long?
DD decimal degrees (OGC standard) DDM decimal degree minutes DMS degree minute seconds
What kind of file type does Microstation create?
DGN
What kind of file types does AutoCAD create?
DWG DXF
How would you comply with HIPPA laws if asked to map medical data?
Data anonymization, hex map, heat map, etc
What is primary GIS data? Give an example.
Data collected in a digital format for a GIS project If you're working on a salmon restoration project: GPS points of stream centerlines
Natural Breaks (Jenks)
Data is clustered naturally into classes Software looks for natural "breaks" in the data.
What is the difference between schema and a data model?
Data model is more high level, describing tables, relationships, feature classes Schema is more detailed, field names, domains, character lengths, etc
What is ordinal data? Give an example of ordinal data.
Data that has been given a predetermined order or rank. Meaning, you cannot compare them with numerical values (0-10 is poor but you will not have the 0-10 value in the data) Good, Fair, Poor would be an example of ordinal data in a RoadwayCondition dataset.
What is secondary GIS data? Give an example.
Data that's derived from other sources (Federal, State, older projects) in support of the GIS project. If you're working on a salmon restoration project: Historic, georeferenced maps of potential pollution sources, NOAA bathymetry data
What is a DBF file type?
Database format, used by shapefiles and is a standard exchange format
45.123° is in what format?
Decimal Degrees
What is topology?
Defines rules and relationships among features Provides a system for giving priority to features of greater accuracy
What is a central meridian? What is it used for?
Defines the central part of the projected coordinate system, used to transform a projection to be more accurate for a specific location. For example, you would move the central meridian of state plane north to Woodinville if mapping the city.
45° 30.123 is in what format?
Degrees and Decimal Minutes
45° 30' 15" is in what format?
Degrees, Minutes, Seconds
How would an image analyst check the accuracy of their classifications?
Determine a set of random areas, compare that to a photo or field verify them, create an error matrix that compares the amount of correctly identified points to the number of sample points collected (percentage of what was correct)
Why were state plane coordinate systems originally developed? When were they developed?
Developed in the 1930s to permanently record original land survey monument locations
When selecting by location, what does "contain" select?
Differs from complete contain. A polygon of the US will contain the state of Texas, even though it shares a border with Mexico.
What is a DOQQ?
Digital Orthophoto Quarter Quad (aerial photo)
Azimuthal projections preserve?
Direction (Angle)
What is the difference between discreet and continuous data?
Discreet data is often vector data where you add attributes and it describes one specific location or asset Continuous data is often raster data, where a surface is "continuous" and includes "fuzzy" data (where does the beach, wetland, and grass begin/end?)
Equidistant projections preserve?
Distance
Arithmetic Operator: / means what?
Division
Why is metadata important?
Document accuracy of the data Provides info about source, projection, description, how often it's updated
What field type is needed to store latitude and longitude?
Double
Which can hold more digits, float or double?
Double (15 significant digits)
What two file types can store both vector and raster data?
EMF and PDF
What is an .img file extension?
ERDAS Imagine - Aerial Imagery It is a raster
What are examples of image types that store georeferencing information in the header of the image file?
ERDAS, IMAGINE, bsq, bil, bip, GeoTIFF, and grids, store the georeferencing information in the header of the image file.
ASCII files are associated with what company and what file type?
ESRI GRID
When selecting by location, what does "completely contain" select?
Each point in the source feature must fall inside the geometry of the target feature The United States complete contains Kansas but not Texas, because the southern Texas boundaries overlap the country boundary.
What is a digital line graph?
Early GIS vector datasets derived from USGS topo maps. Most of the features of the USGS topo (contours, roads, faults, public land survey, etc.) are included. Can be converted to a GIS dataset in ArcGIS. No news ones have been created since mid 1990s.
What is a Digital Line Graph (DLG)
Early GIS vector datasets that were derived from USGS topo maps. Most of the features on a USGS topo map are included in a DLG (lakes, rivers, roads, etc)
What is EDM? What tool uses it?
Electronic Distance Measurement, used in Total Stations for measurement
Quantile
Equal number of features per class
Equal Interval
Equal rnage of values in each class
What does == mean? What does != mean?
Equal to, not equal to
What does the == operator mean in Python?
Equals
Which map projection would preserve distance?
Equidistant
What cartesian coordinate system is best for preserving distance?
Equidistant Conic
What are the advantages of a web service?
Fast and direct access to GIS data OGC standard web services are supported by many mapping applications
What is a planimetric element?
Feature that are independant of elevation, such as roads, building footprints, and rivera nd lakes.
Each GIS dataset contains 3 elements. What are they?
Features, Attributes, Spatial Information (Projected or Geographic Coordinate System)
What does FGDC stand for?
Federal Geographic Data Committee
Tables are made up of columns and rows. What are columns and rows called in a database?
Fields, Records
NoSQL databases are not SQL databases and store _________ and do not require tables
Files
Photogrammetrists
Find positions of features and the angles and distances between them by measuring from photographs and analyze data to determine landcover
What is meant by first return and second return LiDAR data?
First return is the very first return and will show treetops, leaves, branches, etc Second return will usually shoot through the treetops and give a better indication of ground shape
Defined Interval
Fixed interval, usually user defined
What is oblique imagery?
Flown at an angle, shows sides of buildings and features
When selecting by location, what does "are crossed by the outline of" select?
For this operator, the boundaries of the source and target feature must have at least one edge, vertex, or endpoint in common but must not share a line segment.
What did URISA explore in 1999?
Formed a committee to explore GIS certification and this work lead to the creation to the GIS Certification Institute
Coordinate system used to project onto a 3D model
GCS (geographic coordinate system)
How is GIS different than CAD, Photogrammetrists, & Cartographers?
GIS introduces spatial and temporal analysis
What is GLONASS?
GLONASS is the name of the Russian GPS system
Does OGC endorse the shapefile or GML as a format?
GML
What is the difference between GML and KML?
GML is a way of differentiating different objects on the ground (4 lane roads, 2 lane roads) whereas KML is the way to visually display those elements,.
Globally, what is the preferred spheroid?
GRS80
State plane is based on what spheroid?
GRS_1980
What is Galileo?
Galileo is the European Space Agency's satellite navigation system that is currently under construction.
What do raster pyramids do? What are the cons?
Generalize a raster to make it display faster Raster pyramids need space
What is GNSS used for?
Generic name for all GPS type systems
What is an example of an object oriented relational database?
Geodatabase (ESRI)
What do geodesists do?
Geodesists use datums to shift the spheroid so that it fits one spot on the Earth really well
What is a geographic coordinate system? What are some examples of a geographic coordinate system?
Geographic coordinate systems use lat/long to define a location on the Earth
What does the term "geomatics" mean?
Geomatics is the gathering, storing, processing, and delivering geographic information. It is an all encompassing term for GIS.
What does geomatics mean?
Geomatics is the scientific term for gathering, storing, and processing geographic information. Umbrella term for surveying, geospatial engineering, etc.
What is a web processing service?
Geoprocessing tools and models
What are some ways to accurately georeference?
Georeference correctly with low RMS Digitize in correct coordinate system Digitize consistently Digitize enough vertices Set fuzzy tolerance and snapping appropriately
What do world files store? What do they not store?
Georeferencing information, not projection information
What file formats are OGC standards? Name the six.
Geotiff Kml/kmz LAS Geopackage GML OGC and ISO simple features
GNSS
Global Navigation Satellite Systems, the term used for navigational satellites
What is a histogram? Why is it used?
Graph that shows the number of times a value occurs in a dataset Visually see how data is spread out in a dataset, where most values fall.
What advantages do TINS offer?
Great at representing a surface and capturing linear features like roads, bridges, ridge lines
The Prime Meridian runs through what city?
Greenwich, England
What does HIPPA stand for? What is it for?
Health Insurance Portability and Accountability Act of 1996. HIPPA laws protect individuals' medical records and other personal health information.
What is a HARN? What is it based off of? What coordinate systems use HARN?
High Accuracy Reference Networks based off of state level revisions to NAD83 State Plane
What is geometric accuracy?
How close a mapped location is to its real world counterpart
What is a spectral signature?
How light is reflected off of an object. Each pixel in a raster has a spectral signature and can be used to categorize or classify the data (grey pixels are concrete, green pixels are trees, etc.)
What is frequency in terms of data management?
How often a value occurs in a dataset. 1,2,2,2,2,2,3 1 = 1 2 = 5 3 = 1
When would you choose the IDW interpolation method?
IDW will average where there is no point data and "smooth" out the ENTIRE surface. The closer a point is to the center of the cell being estimated, the more influence, or weight, it has in the averaging process. Cons: It does not preserve all the data points.
Which ISO standards does the FGDC endorse?
ISO 119115, ISO 119115 NAP ISO 19139 (just remember, two types of 115, one type of 139)
What is the ISO 19115? What about ISO 19115 NAP?
ISO 19115 is a content standard that defines what information should exist in a metadata document. ISO 19115 NAP is the "North American Profile" developed to accommodate multiple languages (English & French)
When is it appropriate to leave off a North Arrow on a map?
If North is more than one direction (polar maps in conical projection, for example)
When selecting by location, what does "contain Clementini" select?
If a selecting feature sits on the boundary of a feature, it won't be selected. A parcel does not contain a river if the river flows exactly on the border of the parcel.
The following expression would result in what from the raster calculator? Con("elevm"==0 | "elevn" > 100, -99
If the elevation is equal to zero, or the elevation is greater than 100, set to -99.
The following expression would result in what from the raster calculator? Con("elevm" > 30, 1, 0)
If the elevation is greater than 30 return a 1, if not, return a 0
The following expression would result in what from the raster calculator? Con("elevm" > 30, 1)
If the elevation is greater than 30 return a 1. There will be no value associated with anything else.
When selecting by location, what does "within Clementini" select?
If the feature sits entirely on the boundary of the selecting feature, it will not be selected. A crime that happened on the road that forms the boundary between two police districts will not be within either police district.
When would Vertical Exaggeration of Elevation be used?
In order to create a more dramatic hillshade or other effect
What spheroid is used in the United States?
In the United States the preferred spheroid is GRS_1980 which NAD83 is based off of.
What is an index? What are the pros/cons?
Indexes speed up querying but can slow transactions and editing if applied to enterprise data
Discrete rasters have _________ points
Integer
Arithmetic Operator: // means what?
Integer Division
What does // mean? What would 5 // 2 = ?
Integer division 2. Integer division takes the whole value and drops the remainder
What does ISO stand for?
International Standards Organization.
How does the "cubic" technique resample a raster?
Interpolates the value from the 16 surrounding cells
How does the "bilinear" technique resample a raster?
Interpolates the value from the surrounding 4 cells
What does ∩ mean?
Intersection
What type of data is best represented by varying shades or varying intensities of the same color ?
Interval and ratio data (shows quantitative differences)
What is interval data? Give an example of interval data.
Interval data is ordered and the interval difference is meaningful only within the data category itself (you couldn't compare Fahrenheit to Celsius, for example) For instance, zero degrees Fahrenheit and zero degrees Celsius are different temperatures, and neither indicates the absence of temperature.
What is geodesign?
Involving multiple professions, stakeholders, technology, data, and techniques to design a solution to a spatial problem
What is raster classification noise?
Isolated pixels (if in the middle of the lake there is a small cluster of "concrete" pixels it's an error)
Lines of equal value: A map showing thickness?
Isopach (used in oil & gas, hydrologic survey) Shows areas of equal thickness across a surface
How does the "nearest neighbor" technique resample a raster?
It assigns a value from the closest cell
What is system replication? How is it different from a backup or archive?
It backs up the entire system, useful for emergency response, E911 operations
Is a PDF vector or raster?
It can be both
What is an .sid file type?
It is a compressed raster
What is Well Known Text (WKT)?
It is a unique name for each coordinate system WGS84 Web Mercator, for example.
What is a confidence interval? How is it used?
It is used to calculate a range of values where the mean SHOULD fall and can validate a calculated mean.
What does an .LAS file store? What is it from?
It stores velocities from LiDAR data
How is a raster catalog or mosaic raster dataset best described?
It's a "quilt" of raster data that allows quick retrieval and storage so you don't to load the entire file (county cut into 100 different rasters rather than 1 huge raster, for example)
Who is in the FGDC? What does the FGDC do?
It's an organization of federal geospatial professionals chaired by the Department of the Interior. Provides oversight and direction for geospatial decisions across the federal government
What compression types are lossy?
JPEG 2000 MrSID ECW
What types of data do REST services support?
JSON & XML
Give 4 Examples of File Based Standards from the OGC
KML/KMZ, GML, OGC and ISO Simple Features, Geopackage
What is Kappa Coefficient? How is it different from Cohen's Kappa?
Kappa is 1.0 when agreement is perfect; it is 0.0 when agreement is no better than would be expected by chance. AKA Cohen's kappa (they're the same)
What is kerning?
Kerning text has a space dedicated for each letter based on the letter's size, not all letters get the same amount of "space"
What does KML stand for? What is a KMZ?
Keyhole Markup Language (Google Earth) KMZ is a zipped KML
What are benchmarks?
Known points (control stations) across the United States with exact locations
When would you choose the Kriging interpolation method?
Kriging is good at predicting data if no points exist, and good if there are clusters of data with large gaps in between Cons: Takes a significant amount of processing
What are the 2 frequencies of GPS signals? Which is mapping grade, which is survey grade?
L1 (mapping) and L2 (survey)
What compression types are lossless?
LZ77 Run length encoding
If you're mapping Russia, what would be the best projection to choose?
Lambert Conformal Conic
What cartesian coordinate system is best for preserving shape?
Lambert Conformal Conic
What projection is used for states that are elongated in the east-west direction?
Lambert Conformal Conic - TENNESSEE
A point in North America would have what values?
Lat = Positive, Long= Negative
For GPS signals, what level of accuracy does the government commit to?
Less than 7.8 meters or 25.6ft
What are the edges of a TIN good at representing?
Linear features on the ground
What are index contours?
Lines drawn thicker or darker to help interpret contour maps
What is LGIM?
Local Government Information Model is a government database schema
What are focal operations in Map Algebra?
Looking at a fixed area around a cell, flow direction, visibility analysis (viewsheds)
In which cases would you use a join rather than a relate?
Many to One, One to One
What is the performance difference between a map service and a feature service?
Map services render server side, feature services render on the user side
What is shown on a Small Scale Map?
Maps that cover larger areas Easy way to remember: A building on a small scale map is small
What is shown on a Large Scale Map
Maps that cover smaller areas Easy way to remember: A building on a large scale map is large
Where is the geographic center of the US? Why is it important?
Meade's Ranch Triangulation Station Used to create reference grid and benchmarks for the United States
Angle of Deflection
Measured as a positive or negative angle away from the previous line.
What is Moran's Index? What does a positive/negative/zero value mean?
Measures spatial autocorrelation Positive values: similar values are clustered together Negative values: dissimilar values are clustered together Zero: no spatial autocorrelation
Generally, what type of projection would be best to map an area on the equator?
Mercator
Which map projection would preserve direction?
Mercator
What are some common uses for XML data in GIS?
Metadata, GDB Schema, Exporting Database (data & schema), Format of GML & KML/KMZ
State Plane Coordinates 1983 (SPC83) are published in which units of measure?
Meters
What is an XLS or XLSX file type?
Microsoft Excel
DGN is a file type for what software program?
Microstation
Which of these IS NOT a SQL database? PostgreSQL, MySQL, SQL Server, SQLite, MongoDB, Oracle, Informix
MongoDB
What is the ESRI name for a Raster Catalog?
Mosaic Raster Dataset
Arithmetic Operator: * means what?
Multiplication
What is the angle in the previous flashcard in Quadrant Bearing? How do you measure it?
N45E Split the circle into 4 parts, identify the NW, NE, SE, SW quadrants. North and South are 0 degrees, East and West are 90 degrees
What was the first datum calculated for the United States? What spheroid was it based off of?
NAD27 Based off of the Clarke 1866 Spheroid
Name 3 common datums
NAD27 NAD83 WGS84
What coordinate system is 4267?
NAD27 GCS
Which datum is based off of fits from control points? Which datum is Earth centered?
NAD27, NAD83
Name 3 common US Datum transformations
NAD27-NAD83 NAD27-WGS84 NAD83-WGS84
What datum is currently used for projected coordinate systems in the United States? What spheroid was it based off of?
NAD83 Based off of the GRS80 Spheroid
What coordinate system is 4269?
NAD83 GCS
Name 2 common vertical datums
NAVD88 NGVD29
What is NAVSTAR?
NAVSTAR is the name for the GPS system of the United States
Is State Plane a projection?
NO, it is a Geographic Coordinate System.
Which is a proper SQL query syntax? Name LIKE "%City" or Name LIKE '%City'
Name LIKE '%City' When in doubt, use SINGLE QUOTES
What is NAIP? When does the program acquire data?
National Agriculture Imagery Program Acquires data during the growing season, aims to have data available 1 year after collection
What is NDOP?
National Digital Orthophoto Program
Who produces DEMs?
National Mapping Division of the USGS
Points south of the equator have what value?
Negative
Points west of the Prime Meridian have what value?
Negative
Can you calculate area in lat/long?
No
Is the shapefile an OGC standard?
No
Is a projection file (.prj) required for a shapefile?
No, but it is ideal
Does the FGDC still endorse SDTS?
No, it was removed in 2014
Does the FGDC create metadata standards and the NMAS?
No, the Bureau of the Budget creates both metadata standards and the national map accuracy standards (NMAS)
Will a DEM pick out buildings, trees, and other distinct objects?
No. A Digital Elevation Model (DEM) is a representation of the bare ground (bare earth) topographic surface of the Earth excluding trees, buildings, and any other surface objects. A bare-earth elevation model is particularly useful in hydrology, soils, and land use planning
Is Microsoft Access a relational database?
No. Access is the front end of Microsoft Jet Engine, which is the relational database.
Are all CAD drawings spatially referenced?
No. For example, a floating oil well is designed with CAD on land and then put into place out into the ocean.
Can you georeference an image to an unprojected coordinate system?
No. The image must be georeferenced to a projected (cartesian) coordinate system
What type of data is best represented by differing shapes, colors, textures rather than differing sizes?
Nominal data (shows qualitative differences)
What is nominal data? Give an example of nominal data.
Nominal data is categorized and given names. The data value is an arbitrary code (1 = concrete, for example) Fir, Juniper, Ponderosa, Cottonwood in a TreeType dataset would be an example of nominal data.
Which projection map best preserves all distortions? If you don't want any distortion, what is the best option for mapping the entire World?
None, they all have some kind of distortion. A globe.
Is the CSDGM standard required by the FGDC? If not, what does it endorse?
Nope. It is still in use but the FGDC now endorses ISO standards and recommends ISO for organizations just getting into GIS & metadata
What is NDVI? What is it used for?
Normalized Difference Vegetation Index Used to assess plant health. Actively growing vegetation will reflect lots of IR, sick will reflect little IR
In a Venn Diagram of two circles, if both circles and the middle are shaded, that represents what function?
OR Show Circle A or B
What are the advantages/disadvantages of SOAP services?
Older technology, only allow XML data More security options
What is the difference between serif and sans serif?
One has feet, one doesn't. Arial is an example of a sans serif font, Times New Roman is a serif font
What are the 4 types of cardinality?
One to One One to Many Many to One Many to Many
What are local operations in Map Alegbra?
Operations that are independent of neighboring cells. Evaluated cell by cell.
Arithmetic Operator: % means what?
Operator
Map Algebra: What is a relational operator?
Operator that establishes a relationship between the two vales. == Equal <> Not Equal < Less Than > Greater Than < Less Than or Equal > Greater Than or Equal
Map Algebra: What is an arithmetic operator?
Operator that uses addition, subtraction, multiplication, and division.
What does the | operator mean in Python?
Or
What does | mean in Python?
Or
What are two examples of a RDBMS?
Oracle, SQL Server
What type of data is best represented by differing sizes of same shapes?
Ordinal and interval data (shows quantitative differences)
What are some examples of unreferenced data?
PDF plans, scanned maps
What is the order of operations?
Parenthesis, Exponents, Multiplication, Division, Addition, Subtraction
What kind of license do you need to fly a drone higher than 400ft?
Part 107
What are the preferred steps in a data collection process?
Plan project, test out data collection in a sample area, check the accuracy of that data, collect the rest of the data
What are 6 examples of 3D GIS data?
Point lines and polygons with Z values Rasters TIN Multipatch Point Cloud LiDAR
What are control points?
Points that have exact matches between the referenced and unreferenced datasets
What order should GIS data be displayed (top - down)?
Points, lines, polygons
What can a geodatabase hold?
Points, lines, polygons, multi-point, multi-patch, rasters, tables, annotation, networks, relationship classes, topologies
What is PDOP? What is it used for?
Positional Dilution of Precision Describes how good satellite configuration is for collecting accurate points. A lower PDOP is better. PDOP improves if there are more satellites spread evenly throughout the sky. Clusters of satellites would present a high PDOP because of the limit of satellites at all angles to triangulate an accurate position.
Points east of the Prime Meridian have what value?
Positive
Points north of the equator have what value?
Positive
Name 4 open source relational databases
PostgreSQL, MySQL, MongoDB, SQLite
What is precision? How is it different from accuracy?
Precision is about process and consistency. If you take 5 GPS locations using the same device, do they all fall in the same area? A location can be precise but inaccurate.
123.123456 Precision? Scale?
Precision of 9 Scale of 6
What is a primary key? What is a foreign key?
Primary key is the unique ID in the original table, the foreign key is the value in the related/joined table that matches the primary key.
DEMs are produced by whom? What scale are they delivered in?
Produced by National Mapping Division of the USGS using the same extents as the USGS 1;24000 topo maps. Compiled into a single DEM for National Elevation Dataset
What are some of the components of a projected coordinate system?
Projection, Datum, Central Meridian, Units of Measure, Offsets
Projections that preserve areas are called what?
Projections which preserve areas are called equivalent or equal-area projections
What is the difference between a proportional symbol and a graduated symbol?
Proportional symbols scale in proportion to the value in the data (a point with a value of 10 would be 10x larger than a value of 1) whereas a graduated symbol creates ranges of values to represent the different classes of data
What situations would you use generalization?
Protect individual privacies, remove unnecessary vertexes, polygons, create clusters of point data
What does the Federal Bureau of the Budget do in regards to mapping?
Publishes the National Map Accuracy Standards (NMAS)
Would would RGB color 155, 0, 155 be?
Purple
The raster calculator uses what syntax/language?
Python
Topology is an example of QA or QC?
QC - it is done after the data has been collected
What are the different quality levels of LiDAR data? Which is best? Which is worst?
QL0, QL1, QL2, QL3 0 is best, 3 is "worst"
Training team on data collection methods is an example of what?
Quality Assurance
What is the difference between Quality Control and Quality Assurance?
Quality assurance deals with processes and procedures to assure that the data is collected accuractely and consistently Quality control is done after data is collected to make sure that it is accurate and complete
What are two terms for ArcGIS Server services?
REST SOAP
What are 3 ways to specify color?
RGB CMYK HSV
What kind of data stores values across a surface?
Raster data
How do you define raster resolution?
Raster resolution is the size of the grid cell of the raster. If a pixel is 2ft X 2ft the resolution is 2ft.
What are the GISCI code of ethics?
Read definition online (www.gisci.org/ethics/codeofethics.aprx) likely a question about conflict resolution
What is RTK? What is it used for?
Real Time Kinematic. RTK is used for high accuracy GPS locations and uses a station and rover. The station stays in one place and collects a high accuracy signal and the rover uses that signal to correct it's own position.
Do GPS receivers receive their location from satellites or determine the location on their own?
Receivers use triangulation of different satellites to determine their position on Earth
What would RGB color 155, 0, 0 be?
Red
What does generalization do to data? What are some advantages of generalization?
Reduces detail in the data. Declutter the map when zoomed out, make it draw faster, hide sensitive information
What are zonal operations in Map Algebra?
Related to classes in which the pixels belong Two rasters one that displays temperature and one of land use types and you want to know the temperature of each land use type.
1:1000 is an example of a ________________ scale?
Representational Fraction Scale
What does REST stand for?
Representational State Transfer
What should you do if your basemap and scanned map are in different coordinate systems?
Reproject basemap to a projected (cartestian) coordinate system
What does georeference mean?
Required to convert analog data to digital data.
What should the residual error be for georeferenced data?
Residual should be 10x less than mapped feature (review this and check)
What is RMSE? What does it stand for? What is it used for?
Root Mean Squared Error Used to show the difference between where you say the points are and where the software says the points are
What is SPS? How does it relate to GPS data?
SPS stands for Standard Positioning Service. The government is committed to providing GPS accuracy levels specified in the SPS.
What is SBAS? What is it used for?
Satellite Based Augmentation System. Used to obtain high accuracy GPS locations and uses different stations around the US that then send their differential correction data to a satellite and then back down to the receiver so it can correct it's position based on the station signal & GPS signal.
Do SPS accuracy commitments apply to receivers or satellite signals?
Satellite signals. They do not guarantee the accuracy of individual GPS devices.
Informix and DB2 are examples of _____________ relational databases
proprietary
Define the similarity transformation type of georeferencing. What does it preserve?
Scale, rotate, and translate. Only uses 2 control points so it preserves the shape of the original raster (straight lines stay straight)
What kind of rasters are not continuous?
Scanned maps and land use maps
What would this query select? StreetName = "Olive" AND SpeedLimit = 55 OR SpeedLimit = 55
Segments of Olive that are 55mph and any road segment with a speed limit of 55mph.
What would this query do? MOD(Contour, 5000) = 0
Select contours that when divided by 5000 = 0
What type of font is appropriate for geographic features like mountains, oceans, lakes, etc?
Serif fonts
Conformal projections preserve?
Shape
How is a shapefile different from a feature class?
Shapefiles cannot store topology, subtypes, domains, and are limited in character length and field name length
What is geodesic distance?
Shortest distance between two points on Earth taking into consideration the curvature of the planet.
When would you use a scatter plot to represent data?
Showing relationship of two different data
What is a hierarchal database?
Similar to file structures in a network folder, each record is a "child" of the "master" record.
What does SOAP stand for?
Simple Object Access Protocol
What is the difference between a single band and multiband raster?
Single band rasters have only one value for each cell while multiband rasters may have several values for each cell Single Band examples: scanned maps Multiband examples: Satellite images, aerial photos
Is generalization better used for larger or smaller scaled maps?
Small
What are the 4 obligations of a GISCI professional?
Society, Employers and Funders, Colleagues and Profession, Individuals in Society
What is a world file?
Some image formats, such as ERDAS, IMAGINE, bsq, bil, bip, GeoTIFF, and grids, store the georeferencing information in the header of the image file. ArcIMS uses this information if it is present. However, other image formats store this information in a separate ASCII file. This file is generally referred to as the world file, since it contains the real-world transformation information used by the image. World files can be created with any editor.
Why is one spheroid chosen over another?
Some spheroids fit parts of the Earth better.
What are 3 kinds of accuracy for Remotely Sensed Imagery?
Spatial Accuracy (is what is being returned in the right spot?) Spectral Accuracy (is what is being returned true?) Classification Accuracy (user defined classification)
What does SDTS stand for? Is it for data accuracy or map accuracy?
Spatial Data Transfer Standard SDTS deals with the exchange of spatial data, not maps and is for data accuracy, not map accuracy
What is SDTS? What is it used for?
Spatial Data Transfer Standard Sets standards for data conversion so that various software can read other software's data without losing any information
What does SDE stand for?
Spatial Database Engine
What is an SRID?
Spatial Reference Identifier Used to quickly identify coordinate system WGS84 GCS = SRID 4326
Should a map of a city/county use a spheroid/ellipsoid or a sphere?
Spheroid or Ellipsoid. Spheres work fine for small scale (1:5,000,000) maps but larger scale maps need to use a spheroid.
What are datums based off of?
Spheroid/Ellipsoid
BIL, BIP, & BSQ are methods for _____________?
Storing raster image data
What is the difference between supervised and unsupervised classification?
Supervised classification is manual or defined classification by a user and unsupervised classification is essentially computer automated classification.
When someone says "wire frame model", what are they referencing?
TIN
What are 3 ways to show elevation data?
TIN (triangulated irregular network), Profile, Raster
What is a Delaunay triangulation?
TINS use it to create "wire frame models" It maximizes the minimum angle of all triangles and tries to avoid creating "sliver" triangles
What should you do first when designing a geodatabase?
Talk to the stakeholders and gather business requirements
When do you use quotes and when do you not use quotes on data for queries in SQL?
Text needs quotes, integers do not
What is a .mdb extension on a folder mean? What is the size limit?
That is is a personal geodatabase Size limit is 2GBs
What is a .gdb extension on a folder mean?
That it is a file geodatabase
What is 3DEP?
The 3D Elevation Program of the USGS Uses LiDAR to capture elevation data throughout the United States
What planet is an oblate ellipsoid?
The Earth! The Earth rotates around it's minor axis (equator)
What is Compass/Beidu?
The GPS system of China
What is 3DEP?
The National 3D Elevation Project
What is the NED?
The National Elevation Dataset
What does the OGC do? What does F.A.I.R. stand for?
The Open Geospatial Consortium is an internal industry consortium of companies, government agencies, and universities. OGC standards are developed by members to make location information and services FAIR (Findable, Accessible, Interoperable, Reuseable).
What is RMS Error? What is RMSE?
The average of the distances between the mapped location and the actual location. Both are the same.
What is a node?
The beginning or end of an edge
Distances are only true from what point on an Azimuthal or Planar projection?
The center of the map
Accuracy of data is limited by what?
The collecting device. If the collecting device can only collect data every 10ft, you cannot have a resolution of 2 ft.
What is Datum Shift?
The error when displaying data in 2 different datums
Where does NAD27 get less accurate?
The farther you are from Meade's Ranch Kansas. 200M error in Alaska, 400M error in Hawaii.
What is temporal resolution in a raster?
The frequency in which images for the same area are collected (once a day, once a week, etc)
The National Geodetic Survey group of NOAA manages what?
The geodetic framework for the United States
In statistics, what is the median?
The middle value of a dataset 1, 2, 3, 4, 5. 3 is the median.
MAUP?
The modifiable areal unit problem (MAUP) is a statistical biasing effect when samples in a given area are used to represent information such as density in a given area. If you have data and choose to examine it in a 4000 ft2 shape, it will always differ depending on that shape even though it encompasses the same area.
In statistics, what is a mode?
The most common value in the dataset 1, 2, 2, 2, 3, 4, 5 2 is the mode
How do you determine the bits of a raster?
The number of values is: 2 to the power of the number of bits 4 bits = 16 values
How large of a pixel size do you need for a mapping project?
The pixel size needs to be 1/2 the size of the object that you're mapping. If mapping 8ft sidewalk, you will need 4ft pixel resolution.
What is "fuzzy tolerance"?
The point at which 2 different points are considered the same.
What is photogrammetry? What does a photogrammetrist do?
The science of making measurements from pictures, aerial photographs, and images. Measurements are captured from overlapping pairs of photographs using stereo plotters.
When selecting by location, what does "completely within" select?
The source feature must fall COMPLETELY within the target feature. Wyoming is COMPLETE WITHIN the United States. It shares no international border. However, Montana would not be because it shares an international border.
An NDVI value of 1 would mean?
The vegeation is growing rapidly
What is an .AUX or .AUX.XML file? What do they store?
They are raster auxiliary files, they store information that a raster cannot store (statistics, histogram, table, pyramid file, color map, etc)
When selecting by location, what does "are within" select?
This method differs from the Are completely within method in that the geometry of the target feature must fall inside the geometry of the source feature including its boundaries.For example, using this operator, the state of Montana will be selected even if its boundaries partly overlap that of the country.
Besides location, what do GPS satellite signals contain?
Time signal was sent and satellite position at time of signal
What fields are mandatory for ISO datasets?
Title, Date, Geographic Location, Language, Topic Category, Abstract, Metadata
What elements are required on a map?
Title, Legend, Scale
When would you use a divergent color ramp?
To show when values are above or below a mean or median value (elevation - above or below sea level)
What is ortho imagery?
Top down imagery, corrected to be exactly top-down view
What is a total station? How is it similar/different than a theolodite?
Total stations incorporate laser pulses to measure angles and only need one person to operate it (unlike theolodites which need 2 people, one on the staff, one on the theolodite). Total stations are more effective at measuring long distances and can compute the angles & trigonometry instantly, rather than after the fact by a surveyor.
What are transactions in a database? What are the two types?
Transactions are edits or changes in the database. Can be long (editing multiple features) or short (changing one value) Versioning helps by letting users "check out" data for long transactions to ensure data integrity
What is a transit?
Transits are simpler forms of a theodolite and the pros are that it is lightweight.
What cartesian coordinate system is best for preserving direction?
Transverse Mercator
What projection is UTM based off of?
Transverse Mercator
If you're mapping Chile, what would be the best projection to choose?
Transverse Mercator Limited distortion north-south, lots of distortion east-west
What projection is used for states that are elongated in the north-south direction?
Transverse Mercator - CALIFORNIA
What is a TIN?
Triangulated Irregular Network
Decimal Degrees is an OGC standard. True or False?
True
If an image has geographic data stored in the header, you can override it by creating a world file. True or false?
True
KML is an OGC standard, true or false?
True
T or F: NAD83 State Planes are in meters, but states clarify which type of feet should be used in their state.
True
T or F: No map has true scale (accurate distance) everywhere
True
True or False? Output rasters from the raster calculator can be the same data type as the raster or binary.
True
Map Algebra: What is a Boolean operator?
True or False values are returned
GPS satellites orbit the Earth _________ a day at an altitude of ___________ miles.
Twice a day at about 12,000 miles (11,000 also cited, look for number closest to 12,000)
What is a UAV? What about an UAS?
UAV is the drone itself, UAS is the drone and equipment on the ground controlling the drone
What is a international foot? How is it different from a US Foot?
US Survey foot is .304800609.... of a meter Int'l Foot is .3048 of a meter Can cause problems over a large area
At what altitude can recreational drone pilots fly?
Under 400 ft.
What does ∪ mean?
Union
what is a geopackage?
Universal file format for geodata, based on SQLLiteOpen FormatSupports vector and raster data.gpkg extension
What is the difference between signed and unsigned bits in a raster?
Unsigned bits do not include a negative value. So a 256 bit raster would go from 0-255 A signed 8 bit raster would go from -128 to -127
CAD (Computer Aided Drafting)
Use AutoCad and Microstation to create detailed plans for structures and collect some attributes
What is a projective transformation used for?
Used to correct aerials, taking into account distortion away from from flight path
What is a projected coordinate system?
Used to define a location on a flat, 2D map.
What are supplemental contours?
Used to show small changes in elevation that would otherwise be swallowed by the regular contour interval
What is URE?
User Range Error. The government commits to broadcasting GPS signals with a URE of less than 7,8 meters or 25.6ft.
What is false northing and easting?
Value applied to the origin of a coordinate system to change the X or Y coordinate readings
What is ratio data? Give an example of ratio data.
Values a continuous phenomenon with a natural zero point. Population, Distance, Rainfall - something with meaning when compared to zero.
1" = 1000' is an example of a ________________ scale?
Verbal Scale
What is a VRS? What is it for?
Virtual Reference Station. Network of reference stations that monitor GPS signals and log corrections for reference.
What GCS is GPS reported in?
WGS84
What datum does Web Mercator use?
WGS84
What coordinate system is 4326?
WGS84 GCS
What coordinate system is 3857?
WGS84 Web Mercator
What are the 2 most common reference frames used in the world today?
WGS84 and ITRF 2000 ITRF is the international standard, WGS is the USA standard The difference between the 2 is less than 10 millimeters
What spheroid is used by GPS units?
WGS_1984
What kind of features are italicized?
Water features
What does WFS stand for?
Web Feature Service
Give 5 Examples of Web Based Standards from the OGC
Web Feature Service, Web Map Service, Web Coverage Service, Web Map Tile Service, Web Processing Service
What does WMS stand for?
Web Map Service
What is a web map tile service? What are the advantages?
Web map tile services serve up data in "tiles" so you don't have to pull an entire map if you're only looking at one area
When would you use a bar chart?
When comparing two different data
When would you use a pie chart?
When looking at the composition of a dataset, parts of a whole
When would you use a datum transformation?
When mapping data from 2 different datums
When would you use planar measurement?
When measuring smaller areas
When would you use a geodesic measurement?
When measuring very large areas
When would you use a sequential color ramp?
When not highlighting a value which the range of data falls around (number of moose per acre = light brown to dark brown)
When would you choose the Spline interpolation method?
When you need to keep the original values in your data. Spline is like taking a bed sheet and draping it across poles of different heights. It preserves the peaks and valleys.
How is an intersection defined?
Where 3 or more lines converge
What is a subduction zone?
Where one plate goes under another plate
What is a divergent tectonic plate?
Where plates are moving away from each other (mid Atlantic Ridge, for example)
What is a convergent tectonic plate?
Where plates crash into each other
What are transform boundaries?
Where plates slide against one another
NAD83 StatePlanes are in meters, but each state defines _________?
Which type of foot (Int'l or US Survey Foot) to use
What are some important questions to ask about data to ensure it's accurate?
Who collected the data? Is the right type of data being used? Has it been validated? What is the accuracy of the device used to collect the data? Is the metadata filled out?
What is WAAS?
Wide Area Augmentation System. WAAS combines GPS satellites and geostationary satellites to improve GPS accuracy.
.tfw is an example of what? What is the original file type?
World file. Originally a .tif
What order of priority should these be put in? Header File, World File, Row/Column Information of the Image (an identity transformation)
World, Header, Row
What kind of file type is KML based on?
XML
What types of data do SOAP services support?
XML only
What is the ISO 19139?
XML schema implementation of the ISO metadata standards
In a Venn Diagram of two circles, if the two circles are shaded but not the intersect, that represents what function?
XOR XOR shows false values where both values are the same.
What is xOR? How is it used?
Xor When two bits are identical, XOR coughs up a 0. When the two bits are different, XOR spits out a 1.
Is UTM a projected coordinate system?
Yep
Can a centroid be outside of a polygon?
Yes
Can a geodatabase store vector and raster data?
Yes
Can raster calculators convert between standard and metric values?
Yes
Can you calculate area on a raster?
Yes
Do ISO standards include domains?
Yes
Does a "-" (negative sign) count as a significant digit?
Yes.
Can an area measured in GIS be different than a legal area?
Yes. Legal areas commonly do not line up with GIS measurements.
According to the SDTS, should testing be performed against an independent source of high accuracy, if available?
Yes...
Why is oblique imagery useful?
You can measure the height of objects
What are the two types of MAUP? Explain.
Zone Effect and Scale Effect Zone Effect - Analysis using the same data aggregated into 1 mile grids will differ from analysis using 1 mile hexagon cells Scale Effect - Analysis using the same data will differ based on the scale of analysis. A county level analysis will result in different results than a census tract, even though the same dataset was used.
Certification
a process, often voluntary, by which individuals who have demonstrated a level of expertise in the profession are identified to the public and other stakeholders by a third party
What is a correlation coefficient? What value is a high correlation? What value is a low correlation?
a statistical measure of the relationship between two variables 1 is high, 0 is low.
What is a theodolite?
a surveying instrument for measuring angles
What is a choropleth map?
a thematic map in which areas are shaded or patterned in proportion to the measurement of the statistical variable being displayed on the map, such as population density or per-capita income.
What is an API? What is it for?
application programming interfaces developed to move data between systems and to reuse data
What are 4 types of raster data?
remotely sensed imagery (satellite, aerial) surfaces scanned maps classified images
FALSE NORTHING AND FALSE EASTING
review
Random geometric errors may be corrected through a process known as ____________________?
rubber sheeting
What type of font is appropriate for city names, legends, etc?
sans-serif fonts
what does the k stand for in CMYK?
black
Surveyors
determine exact position of features and the angles and distances between them. Surveyors may collect attributes as they collect locations such as x,y,z values, time, and other attributes
In which cases does a relate work?
support only one-to-many and many-to-many cardinalities
What is Class G airspace?
surface to 1200 ft or less
What is Tobler's first law of geography?
everything is related to everything else, but near things are more related than distant things
What is hypsometry?
the measurement of land elevation relative to sea level
When selecting by location, what does "share a line segment with" select?
the source and target features will be considered as sharing a line segment if their geometries have at least two contiguous vertices in common.
What is geomorphology?
the study of the physical features of the surface of the earth and their relation to its geological structures.
What is OOP?
"Object-oriented programming (OOP) is a programming paradigm using ""objects"" - data structures consisting of data fields and methods together with their interactions
What are the three resolutions in remote sensing?
-Spatial -Spectral (electromagnetic spectrum measured) -Temporal
What are some commonly-used techniques to indicate elevation in a 2D map?
-contour lines -hillshading -hypsometric color. -spot heights
What are the three types of scales that can be used on a map?
1. Bar scale 2. Verbal scale ("1 inch is 200 feet") 3. Representational fractions (1:200)
How many miles are in a kilometer?
1.6
How many significant digits can a double value hold?
15 significant digits
What scale are USGS Topo Maps? In minutes?
1:24,000 (7.5 min X 7.5 min)
What is a pseudo-node?
A point on the line that is usually used to indicate a change in attribute (gravel to pavement, for example)
What's the difference between a projection and a projected coordinate system?
A projection is one part of a projected coordinate system
What is bit depth? Why is it imporant in relation to rasters?
A raster consists of pixels and each pixel can store a certain amount of data. More bits = more ability to store data and can represent finer gradations of color.
Equivalent projections preserve?
Area
What projection would you use for a polar region?
Azimuthal
When doing a raster overlay, both rasters need to ______________?
Be in the same coordinate system
What color 0, 0, 0 be in RGB?
Black
What is variance and how is it calculated? Why is it useful?
Calculate the mean For each number, subtract the mean and square the result Calculate the average of the squared results Take the square root of this average. That is the standard deviation. (Won't need to know how to do it, but need to know how the number is calculated) It is useful because it can quickly identify outliers in your data.
Standard Deviation
Classes defined by how far above/below the mean the values are
What does the Intersect tool do? How is it different from Union?
Combines all of the features in two feature classes and only outputs the common areas of both. Union outputs the intersected features as well as the distinct features from both feature classes where they don't intersect.
What is a DEM?
Digital Elevation Model
What is a DEM?
Digital Elevation Model (elevation raster)
What is a dangling node?
End of the line with no connections
What is a web coverage service? What is it used for?
For sharing raster data, can be used for analysis
Explain the steps from a geoid to a projected coordinate system.
Geoid --> Spheroid --> Geographic Coordinate System --> Projected/Cartesian Coordinate System Approximate the geoid, Equation for the geoid (now really a spheroid), Calculate lat/long coordinates, Push lat/long coordinates through more equations, That equals a projected coordinate system.
What is a discrete raster?
Has been classified into distinct categories
What is IRNSS?
IRNSS is the GPS system of India
What units are used in US Coordinate Systems?
Int'l Feet Feet Meters
Lines of equal value: A map showing air pollution, rain fall, noise?
Isoline
Why is the Robinson Projection used by National Geographic?
It is better at representing higher latitudes than the Mercator projection
How do you determine raster resolution?
It is the size of the individual pixel (if a pixel is 2ft X 2ft it is a 2ft resolution raster)
Is LiDAR data raster or vector data?
It is vector data, rasters are often derived from the raw data
What is a JSON? What is it used for?
JavaScript Object Notation It is commonly used for transmitting data in web applications (e.g., sending some data from the server to the client, so it can be displayed on a web page, or vice versa
How are HTML, XML, and KML related?
KML is based on XML, XML is based on HTML
A point in in Southern Africa would have what value?
Lat = Negative, Long = Postive
Parallels are lines of ----?
Latitude
Map Algebra: What is a logical operator?
Logical values simply keep track of the values, true and false DIFF - Logical Difference (If a cell value is different, one or the other is returned, or if they're the same a zero is returned) IN - Contained in List Over - Replace
Meridians are lines of ----?
Longitude
Object Oriented Data Model
Look at link (review)
LZ77 is _____________ compression and a _____________ compression type
Lossless and Pyramid
Name 4 common projections
MARL! Mercator Albers Robinson Lambert
How do you determine Manhattan Distance?
Manhattan Distance is used to find the distance between two points when something blocks a direct path (such as buildings in midtown Manhattan).
What is does OGC stand for?
Open Geospatial Consortium
Arithmetic Operator: ** means what?
Power
What level of accuracy is required by the 3DEP program?
Q2
What projection is best for mapping higher latitudes? Also used by National Geographic...
Robinson Projection
An NDVI value of .1 would indicate what?
Rocks, sand
What extent are DEMs delivered?
Same as 1:24000 USGS Quad Maps (7.5min X 7.5min)
What are some examples of uncompressed raster formats?
TIFF, GeoTIFF, Esri Grid
What is the preferred PDOP for collecting data? What's a great PDOP?
The lower the PDOP the better. PDOP of 6 is good enough, PDOP of 4 is great.
What is a continuous raster?
Unclassified, shows a continuous surface (temperature, land forms, etc)
What spheroid is preferred globally?
WGS_1984
What are some elements to topology?
What layers? What's the cluster tolerance? Ranks, Rules
What is a geoid?
a model of Earth using mean sea level as a base Earth is not a perfect sphere
Mappers
create visual representations of real world locations and use thematic mapping to show locations and attributes
Continuous rasters have _____________ points
floating
Classification Methods (link)
https://pro.arcgis.com/en/pro-app/latest/help/mapping/layer-properties/data-classification-methods.htm
What is SNR?
signal to noise ratio
What does ^ mean in Python?
xOR
Radian Measures: 180 degrees = ?
πrad