GEOL 4331: Intro To GIS: Exam I Review

What must a surveyor do if he is using a GPS enabled smartpole stadia rod but the GPS sateillite are obsructed from view?

A laser to the line of sight of a SmartStation

Satellites require these types of clocks.

ATOMIC CLOCK.

What increases as the Conceptual Model goes down the levels?

Abstraction

True Direction

Angular relationship are represented correctly

Define some of the features in a Vector Dataset.

- Contain, points, lines & polygons of real or imaginary features on Earth - Downloadable Vector Data - GPS Data collected All Day without sleep - Metadata describes the data but is missing

Emits energy in order to scan objects whereupon a sensor then detects and measures the radiation that is reflected or backscattered from the targe

Active Remote Sensing

Two Main Image Types

Aerial Photographs Satellite Images

Data to Info Conversion (Remote Sensing)

Analog visual Image Processing (using the Element of image Interpretation) Digital Image Processing Hypothesis Testing

Characteristics of Great Circles

1. Every great circle divide Earth into two equal halves called hemispheres 2. Every great circle is a circumference of the Earth 3. Great circles mark the shortest travel routes between locations on earth's surface

Industry Growth In China

2012(30%) and growth by 20%. 81 Billion By 2015 and 163 Billion By 2020. 23,000 Organizations in'volved in China

What is the mean radius of the Earth?

3,959 miles 6, 371.3 Km

Recreation

3-10m $400

At least ______ satellites are in line of sight from almost anywhere on Earth's surface

4

China GTECH Industry Value

42 Billion

Texas NAD83 State Plane Zones

4201 (North), 4202 (North-Central?), 4203 (Central), 4204 (South Central), 4205 (South)

Combination of scanning and manual digitizing.

Heads up digitizing

Mouse on a screen. Digitizes paper maps, aerial photos, or other images

Heads up digitizing

What is a Object Based Vector Model?

In this model, spatial data are treated as objects, i.e., roads, rivers, lakes, parks, etc. Objects contain all of the info and properties to define the object All of them are stored in a single system

Integer

In which case there is an associated value attribute table (VAT) which contains one record for each different value in the raster

What increases as Green leaves absorb more red and blue light

Increase in NIR reflectance

IRNSS

India. Initiated 2006. Being deployed. 1st satellite in 2011

Most error in standard GPS

Selective Availability

is an intentional degradation of the signal once imposed by the U.S. Department of Defense; turned off SA in May 2000

Selective Availability (SA)

Vector data Model

Defined Spatially Point (x and y Coordinates) Line (sequence of Points) Polygon (a closed Set of Lines) Good for representing clearly defined objects

Projected Coordinate System

Defined on a flat, two-dimensional surface. Unlike a geographic coordinate system, a projected coordinate system has constant lengths, angles, and areas across the two dimensions.

A simple geometric form capable of projecting information from globe without compressing or stretching

Developable Surfaces

Distance from satellite

Difference in time from satellite to time received gives distance from satellite. T0 is signal from satellite T1 is signal from receiver therefore D = Speed of Light x (T1 - T0)

....uses the time sequence of observed errors at fixed locations to adjust simultaneous measurements at mobile receivers

Differential GPS

..simultaneous GPS measurements at field-roving (unknown) and base (known) sites

Differential GPS

More accurate measurements if this instrument is left in place longer

Differential GPS

DOQQs

Digital Ortho Quarter Quads - Grayscale or color-infrared (CIR) images - 1-meter ground resolution; - Referenced to the North American Datum of 1983 (NAD83) and cast on the Universal Transverse Mercator (UTM) projection

The process where features on a map or image are converted into digital format for use by a GIS

Digitizing

Advantage of CAD?

Digitizing precision

- Used to digitize hard copy maps into GIS - Transform wire intersections into coordinates of the tablet's coordinate system

Digitizing tablets (Heads down digitizing)

What are The components of A Thematic Map?

Geographic Baseman of The World > Thematic overlay of The world's Largest Cities > Composite of Both maps

What is Visualized on Maps?

Geography

In plane-table survey a special telescope alidade is placed on a leveled plane-table. A line is drawn from the center of the table in the direction of feature of interest, outcrop, tree etc

True

Interval and Ratio data present continuous phenomena and are usually measured with real cell values

True

Latitude goes from 0 to 90º N or S and longitude to 180 º E or W of meridian; the 180 º line is the date line

True

Latitude is North/South of equator. And Longitude West/East of the Prime Meridian.

True

Latitude lines form parallel circles of different sizes, while longitude lines are half-circles that meet at the poles

True

Lines of Lat and Long constitute the Earth's Graticule

True

MAP Ratios are Dimensionless

True

Most GPS are set to WGS84 out-of-the-box (same as NAD83)

True

Multiband Rasters are often displayed as red-green-blue composites.

True

NAD 27 resulted in lat/long coordinates for about 26,000 survey points in the US and Canada.

True

Nominal and Ordinal data represent discrete categories and are represented in integer cell values

True

On-screen digitizing also removes or reduces the need for digitizing tables or map scanners

True

On-screen digitizing is often more accurate than manual digitizing because manual map digitization is often limited by the pointing ability of the operator

True

Originally, the "datum" referred to that "ultimate reference point."

True

Posidonius made measurement using angles to star in near horizon, 38, 600 km

True

Qualitative Maps Are based on descriptive Information(Nominal)

True

Quantitative maps may Use Numerical relationship Between Variables That have been Mapped

True

Reflectance, transmittance, and absorbtance are typically given as a percentage. No units

True

Satellites started collecting geodetic information in 1962 as part of National Geodetic Survey

True

Short segments of pseudo-random codes are unique for each satellite & time

True

Snapping may join nodes, or may place a node onto a nearby line segment

True

Spaghetti data model records each line separately and a shared boundary between polygon can be represented twice.

True

The Spherical Model uses the distance from the hypothetical center of the Earth to the surface (radius).

True

The basis of GPS is triangulation from satellites

True

The circle formed by a slice that does not pass through the center is a small circle (all lines of latitude except the equator are small circles)

True

The ellipsoid is an approximation of the Earth's shape that does not account for variations caused by non-uniform density of the Earth.

True

The feature is the arc, not the line.

True

The geoid is actually measured and interpolated, using gravitational measurements

True

The higher the PDOP value, the poorer the measurement

True

The intersection of Central Meridian of UTM zone and the Equator is the origin of the zone.

True

The sphere is the simplest model of Earth's surface.

True

The surface of the geoid extends across the Earth, approximately at mean sea level at a level set by gravity

True

Thematic Maps Can Show quantitative or qualitative information

True

This height above a geoid is also called the orthometric height

True

Topological info is used to detect errors in spatial data.

True

UTM coordinates are in meters, making it easy to make accurate calculations of short distances between points (error is less than 0.04%).

True

UTM system is transverse cylindrical projection, dividing the surface of the Earth 60 zones, each 6 degree of longitude wide, with the central meridian in the center of the zone.

True

Vegetation indices express the difference between NIR and red reflectance

True

WAAS Only available in North America and Ideal for open land and marine applications

True

You must correct for any delays the signal experiences as it travels through the atmosphere (positional uncertainty)

True

cesium can be used to create extraordinarily precise clock

True

early atomic clocks looked at vibrations of quartz crystal

True

if you have few Points Then you Should Use Size instead of Color value

True

the distance in curvature of a degree of longitude is not constant

True

• In NAD27 center point was Mead's Ranch, KS

True

Force of gravity responds to changes in water volume. Gravity is varying in time and space.

True Water is heavy.

An Object Class is a collection of objects in tabular format that have the same behavior and the same attributes.

True An object class is a table that has a unique identifier (ObjectID) for each record

The shortest distance between two points on the sphere is an arc of a great circle

True Defined by slicing the sphere through the two points and the center (all lines of longitude, and the equator, are great circles).

Globe is nearly a perfect model of our planet

True Displays relationship between landforms and water bodies, relative size and shape of features, and accurate compass directions

Anaximenes believed that the Earth was a rectangular box

True.

Newton and other suggested Earth must be flattened because of centrifugal forces

True.

Raster Models are useful for background maps and for spatial analysis

True.

A Relationship is an association or link between two objects in a database.

True. A relationship can exist between spatial objects (features in feature classes), non-spatial objects (objects in object classes), or between spatial and non-spatial objects.

At 1 degree Longitude you can calculate the rest of the Earth....

True. 1 degree Longitude = 111 x Cos(latitude)

Monochromatic color Scale are A Series of Colors of The Same hue But with Color value Varied from Low to High

True. Common for Choropleth Maps Darker Colors = More Importance

A feature class is a collection of geographic objects in tabular format that have the same behavior and the same attributes

True. Feature Class = Object class + spatial coordinates

In a Simple Raster one value is assigned per cell

True. Integer as a code example: limestone = 1, sandstone = 2, mudstone = 3 -One Raster per theme (Geology>Hydrography>Parcels)

The distance in curvature of a degree of latitude is always equal to about 111 km

True. 110 Km?

The U. S. Air Force lunches, maintains and constantly monitors exact location and of each GPS satellites through ground stations

True. Control Segment

A location measurement accurate to 1 cm horizontally and 2cm vertically is now possible in 3 minutes with a mobile receiver

True. Differential GPS

Saturation is a color Scale That goes from Pure Hue To gray or Black

True. Example Would be from Red To Black

Value is the amount of white or black in the Color

True. Goes blacker Towards The Right

GPS receivers on the ground communicate with the GPS satellites to get continuous, accurate, all-weather world-wide, x-y and z positional information

True. User Segment.

Harmony

Two Adjacent Hues Basically next to each other

Constrast

Two Hues with One Hue Skipped in Between

Compiles all line features used to create a block layer for the entire country

U.S. Census Bureau

Started building a map infrastructure in the late 1970s and early 1980s

U.S. Census Bureau

GPS country of origin?

USA USA USA. Began 1978. since 1994. 31-32 number of satellites

Cartograms

Value by Area map Shows Land areas Sized to reflect The magnitude of The Variable being mapped

Interval data

Values are numerically ordered Interval difference is meaningful Examples are voltage potential and difference in concentration

What are The Two Common methods That Are Used?

Vector data Model and Raster data Model

Coverage

Vector data format introduced with ArcInfo in 1981 - Multiple physical files (12 or so) in a folder - Proprietary: no published specs & ArcInfo required for changes - Can be "exported" to a single E00 (E-zero-zero) file for transfer

Create base map

Vector features or raster images

Can improve accuracy to within 2 meters

WAAS

if you are going to compare with GPS data you have collected elsewhere in the world....

WGS84

National Program by USGS and USDA (NRCS). First cut is by automated. delineation from NED. Hand checked and edited

Watershed Boundary Dataset

When vertices are entered too close together, the GIS will remove some of them in order to reduce the file size

Weeding

Name three ways Digitizing software helps in assisting your digitizing errors

Weeding Snapping (Lines) Snapping (Nodes)

Definition of GIS

a computer based system to capture, store, manipulate, analyze, output, and distribute spatial data and information.

An electrical device with cross hairs and multiple buttons to perform data entry operations and an operator then enters the information using...

digitizing puck

is a hardened surface with a fine electrical wire grid under the surface.

digitizing tablet

One satellite range measurement. The receiver is positioned somewhere....

on the sphere defined by the satellite position and the range distance, r

What are the visible boundaries in TIGER census block groups?

• street • road • stream • Shoreline

Are shape files the most commonly used format?

Yes

Can Adjacent Colors be Used for Harmony?

Yes

Is it good Practice To Use mathematical progression or formula instead of picking arbitrary Values?

Yes

Does spatial data that has topology require additional data files that defines topology?

Yes.

Is topology the science and mathematics of geometric relationships?

Yes.

Are Map features smaller than blocks are the responsibility of local governments? What are the features?

Yes. - deeded land parcels - buildings - street curbs - parking lots

Is the Conceptual Model more Computer Oriented as it goes down levels? Is it Human Oriented at the 'Reality' (upper) level?

Yes. Yes.

Equal Intervals

_ Consistent widths -Easy To Understand _ Use equal width intervals with multiples of 2, 5, 10 0-100,100-200,200-300

Radio waves =

speed of light

Mapping Grade

1m-submeter $5,000-$10,000

The whole system of linked reference and subreference points came to be known as the datum

"ultimate reference point."

Travel Time Saved

$1.1 Billion Hours

Money Geospatial Saves Businesses

$1.4 Trillion

U.S. Industry Value

$73 Billion

Wages Paid Out

$90 Billion

Conic

(Albers Equal Area, Lambert Conformal Conic) - good for East-West land areas. Map looks like half eaten pizza

GIF

(Graphic Interchange Format): - .gif as its file extension. - Ideal for schematic drawings that have relatively large areas with solid color fill and few color variations. - Small file sizes

JPEG

(Joint Photographic Experts Group): - .jpg file extension. - Most widely used format for photographs and other images that have a lot of color variations - Uses file compression at the expense of picture detail, if you specify a lot of compression

Azimuthal

(Lambert Azimuthal Equal Area) - good for global views. This is the circle map.

NGVD29

(National Geodetic Vertical Datum of 1929)

NAD27

(North American Datum of 1927) uses the Clarke (1866) ellipsoid on a non geocentric axis of rotation

Define NAD27

(North American Datum, 1927)

Define NAD83

(North American Datum, 1983)

NAVD88

(North American Vertical Datum of 1988)

TIFF

(Tagged Image File Format) - .tif file extension - Very high quality images - Commonly used in publishing - Sizes are large because it is uncompressed

Cylindrical

(Transverse Mercator) - good for North-South land areas. Normal rectangular almost maps of the world

Define WGS84

(World Geodetic Survey, 1984)

WGS84

(World Geodetic System of 1984) uses GRS80, almost the same as NAD83

Main types of radiation processes in remote sensing

(i) reflection (ii) emission, (iii) emission- reflection

Floating Point

(number with a decimal point) in which case there is no VAT table, and simply one decimal value per cell

Define Coordinate Systems

(x,y,z) coordinate systems for map data

Get data from Continuously Operating Reference Stations (CORS) network

*Post-processed DGPS* - Designed to meet post-processing needs of GPS users - Works with the GPS data you collected out in the field, and adds

Vertical Photography

+- 3º vertical to Earth's surface Uses: • Planimetric base maps • Topographic maps • Raster digital elevation models • orthophotographs

UTM Coordinates

- (Easting, Northing) = (X,Y) - Expressed in meters: Northings (e.g. 4286289) and Eastings (e.g. 0525690) - Each integer equals 1 meter » Easting (walk 1m east, 0525690 > 0525691) » North (walk 1m north, 4286289 > 4286290)

Subdivision of a census tract

- 400 housing units, with a minimum of 250 and a maximum of 550 housing units

MS Access-based Personal Geodatabase

- > 8.0 GIS - Single-user editing, multiple read-only users - Stored as one .mdb (Access) file - Max 2GB total & 250,000 features per layer (effective max is 250-500MB)

File-based Geodatabase

- > 9.2 - Single-user editor, many read-only users - Faster and more efficient than personal gdb. - Unix and Microsoft supported - Max 1 TB (256 TB for raster)

Explain Scanning

- A document is scanned using a digital scanner. The document is typically fed through an opening in the front. - Light is emitted onto the document, and the reflected light is read in by a sensor. The sensor then records the reflected brightness to create an image.

Advantage of Satellite Based Datums

- A spheroid when used as a datum correctly maps the earth such that all Latitude/Longitude measurements from all maps created with that datum agree. - Rather than linking points through surface measurements, they are linked to reference point in outer space

Other sources of RS data

- Airborne (lidar, hyperspectral). - Unmanned (UAV). - Ground sensors

Limitations of UTM

- Although the distortions of the UTM system are small, they are too great for some accurate surveying. - Zone boundaries are also a problem in many applications, because they follow arbitrary lines of longitude rather than boundaries between jurisdictions.

What are some types of Vector Topology?

- Arc-node and node topology - Polygon topology - Route topology - Regions topology

Polygon Feature

- Area of homogeneous phenomena - In polygon layer the lines (arc) define areas

Statement of Problem (Remote Sensing)

- Identify Data to be collected -formulate Hypothesis

CAD Software

- Autodesk, AutoCAD (.dwg) - Bentley, Microstation (.dgn, .dxf)

Things to know about multiband rasters

- Band 1 is at bottom, Band 2 in the middle, Band 3 at the top. - Band represents a segment of the electromagnetic spectrum that has been collected by a sensor

Simple Raster

- Binary - 0-1 stored; feature present or not. B&W image - requires a different raster for each attribute (e.g. rock type) within a single theme (e.g. geology. Limestone>Sandstone>Mudstone = Geology)

What is TIGER?

- Census Bureau's product for digital mapping of the U.S. - Available for the entire U.S. and its possessions

What is TIGER?

- Census Bureau's product for digital mapping of the U.S. - Available for the entire U.S. and its possessions - Include the following geographic features • roads and street centerlines • railroads • rivers • lakes • census statistical boundaries

Spatial Analysis of Raster Data

- Conceptually simple, easy to implement - Well-suited for surface-and field-related phenomena (e.g. elevation, gravity, rainfall etc.) and for discrete features - Wide availability of data-sets; all remotely sensed data of this short - Best suited for "where" rather than "What" questions

Constructs Built from Raster Data

- Connected cells can be formed in to networks - Related cells can be grouped into neighborhoods or regions

What area does DOQQ cover?

- Cover an area measuring 3.75 minutes longitude by 3.75 minutes latitude, approximately 5 miles on each side

ArcInfo Coverages

- Created using ESRI's ArcInfo software - Older format - Set of files within a folder or directory called a workspace - Files represent different types of topology or feature types

How are features presented in a State Plane Coordinate System (UTM)?

- Defined for each State in the United States - East-West States (e.g. Texas) use Lambert Conformal Conic. - North-South States (e.g. California) use Transverse Mercator - Texas has five zones (North, North Central, Central, South Central, South) to give accurate representation - Greatest accuracy for local measurements

Define some concepts behind topology.

- Defines spatial relationships between features. - Each Arc has a beginning and ending node - Arc connects with other arcs at nodes. - Connected arcs that surround an area form polygons (this defines area and perimeter). - Arcs have a right and left side (this defines adjacency).

National Elevation Dataset. Go into detail.

- Digital Elevation Model with 1 arc-second (30m) cells - Seamless in 1° blocks for the United States - 10 billion data - Derived from USGS *1:24,000* quadrangle sheets

What are some features of Vector Arc Feature?

- Each Point has a unique feature - 2 points = line segment - >One line segment = arc - Endpoints of an arc are called nodes - Angle points = vertices - Two arcs meet at nodes

What are the three types of Geodatabases? And what is their main purpose?

- File - Personal - ArcSDE (Manage features and tables inside a database management system)

Rules of Data Table Formats

- First row must have attribute names with self-documenting labels (e.g. Pop5To17, Area) - Usual naming convention. first character is a letter. Remaining characters be any letters, digits, or the underscore character - All additional rows of a data table need to contain attribute values - None of the rows can be sums, averages, or other statistics of raw data rows

Advantages of RS

- Global view. - Multiscale observation. - Frequent observation. - Direct and non destructive observation. - Complete cover. - Non-visible spectral regions. - Height estimation

What are False Easting (False X) and False Northing (False Y)?

- In order to minimize distortion, most projections are centered in the mapping area. - The unfortunate side effect of this is that with the x/y origin in the mapping area, negative x or y values are likely. <To eliminate this possibility, False X and False Y values are chosen and added to all x and y values so that all x/y values are positive> <-- actual answer?

What ways does a Grid store data?

- Integer - Floating Point

Numeric Interval Classification

- Keep the number of intervals as Small as Possible _ Cut Points (break Points) points At which we choose To Break The Total attribute Range

What signals are added to improve functionality?

- L2C to ease GPS tracking for navigation - L5 for worldwide safety and life application - L5 for military application

How do you determine Latitude and Longitude?

- Latitude Φ 60 N - Longitude λ 20 E - Latitude is the angular distance between the plane of the equator and a line passing through the point under investigation and the center of the earth. - Longitude is the angular distance between the prime meridian and the meridian of the point under investigation

What are the three databases associated with GIS?

- MS Access-based Personal Geodatabase - File-based Geodatabase - SDE-based Geodatabase

What is the location reference system for Earth's surface?

- Meridians: lines of longitude - Parallels: lines of latitude - Prime meridian is at Greenwich, England (that is 0º longitude) - Equator is at 0º latitude

What exactly is Grace?

- NASA Mission launched in 2002 - Designed to measure gravity anomaly of the earth - Two satellites, 220 km apart, one leading, one trailing - Distance between them measured by microwave to 2µm - High gravity force pulls satellites together - Lower gravity force, lets them fly apart more - Gravity anomaly = difference from average

What is Raster Data Values consist of?

- Nominal (descriptive) - Ordinal (rank or order) - Interval/ratio (numeric items)

What are the types of data represented in cells?

- Nominal Data - Ordinal Data - Interval Data - Ratio Data

What is A Thematic map?

- Not meant to locate anything with Precision - Displays one or more Specific variables - Income, crime rate, disease, earthquake Center

In a Geodatabase the replacement for coverages have support for...

- Simple features: points, lines polygons - Complex features: real world entities modeled as objects with properties, behavior, rules, & relationships

Satellite Images

- large area coverage - broader spectral range - digital formats - inexpensive for large areas - geometrically accurate

SDE-based Geodatabase

- Personal (4), Workgroup (10) and Enterprise (??) versions - Multi-user simultaneous editing via versioning and long transactions - Uses standard db: ORACLE, SQL Server, etc - Attribute and spatial data in same database

Define point, line, area in a spaghetti data model.

- Point: recorded as a x,y coordinate pair - Line: series of x,y coordinates - Area: series of x,y coordinates. 1st and last coordinates are identical. closed loop polygon

Digitizing converts the features on the map into what three basic data types?

- Points: zero dimensional objects - Lines: one dimensional objects - Polygons: two dimensional objects

What does a Data Model Provide?

- Provides devs to make application domains that can be made into designs and then implemented - Users get a view of the structure of the system. Void from data of specific items and details of some applications.

Conceptual Model Levels.

- Reality - Conceptual Model - Logical Model - Physical Model

Limitation of Surface Based Datums

- Requires line of sight, so many survey points required - Errors compound with distance

What is A Reference Map?

- Road MAP or navigational map for air on Sea They give general Information - Cadastral Map shows property boundaries for The purpose of recording property Ownership for tax assessment - They provide accurate info about different-features

Steps in heads up digitizing

- Scanning the map - Registering the map - Digitizing the map

Name the three ways rasters can be drawn

Monochrome image Grayscale image Display colormap image

What are the four steps in the Remote Sensing Process?

- Statement of problem - Data Collection - Data to Info Conversion - Information Presentation

Personal Database

- Stores datasets in a Microsoft Access .mdb file - Storage sizes between 250 and 500 MB - Limited to 2GB - Only supported on Windows

File Database

- Stores datasets in a folder of files - Each dataset a file up to 1 TB in size - Can be used across platforms - Can be compressed and encrypted for read-only, secure use - ESRI's recommended choice

ArcSDE Database

- Stores datasets in a number of optional DBMSs: • IBM DB2, IBM Informix , Microsoft SQL Server , Oracle, or PostgreSQL - Unlimited size and users

What is a Georelational Vector Model

- Stores spatial and attribute data in separate files - The spatial data (geo) are stored in graphics files and the attribute files are stored in relational database - A georelational dataset uses a common field to link spatial and attribute data - Used for decades

What are the Three types of Digital file formats?

- TIFF - GIF - JPEG

Define The Ellipsoid Model

- The rotation of the earth generates a centrifugal force that causes the surface of the oceans to protrude more at the equator than at the poles - This causes the shape of the earth to be an ellipsoid, and not a sphere. -

What were the twofold needs by Census mapping?

- To assign census employees to areas of responsibility, covering the entire country and its possessions - To report and display census tabulations by area, officials determined that the smallest area needed for these purposes is a city block or its equivalent

What are some repositories for National/State/Global Data?

- U.S. Census - USGS and other government sources - GDT Dynamap/2000 U.S. Street Data - Engineering companies - land surveys, aerial photos, CAD drawings - University Web sites (e.g. Penn State's PASDA) - ESRI

What are some difference between Vector and Raster Data models?

- Unlike a vector structure, which stores coordinates explicitly, raster coordinates are contained in the ordering of the matrix - Raster datasets are defined by: - Origin in X,Y - Cell Size in X,Y - Angle of Y-Axis - Number of Cells in X and Y

Three Problems with CAD Drawings

- Use local drawing coordinates - Individual objects do not have unique identifiers - Focused on graphical representation of objects, and cannot store relationships

Define the Geoid Model

- Variation in the strength of the gravitational pull, cause regions to dip or bulge above or below a reference ellipsoid. - Geoid is the the three-dimensional surface along which the pull of gravity is a specified constant.

Shape File

- Vector data format introduced with ArcView in 1993 - Comprises several (at least 3) physical disk files (with extension of (.shp, .shx, .dbf), all of which must be present - Openly published specs so other vendors can create shape files

Satellite Based Datums

- With satellite measurements the center of the spheroid can be matched with the center of the earth.

What Are fields?

- Worth measuring at every point on The Planet - Radiation, Elevation, Temp, Soil Type & PH, Rainfall, Land Cover Type, and Ownership

Scanning the map (Heads Up)

- a user can scan the map at a high resolution

What are the four directly loadable data types?

- dBase (.dbf) - Text with comma (.csv) or tab-separated values (.txt) - Microsoft Access (.mdb) - Microsoft Excel (.xls)

Define fields

- each Variable has one value everywhere - Variable is A function of The Location - Basically geographic concept as a set of variables, with each Variable having A Value at every Location on The planet

Salaries for Remote Sensing Scientists And Technicians

Scientists: 27,000 in Employment and Growth By 10,100

Shape Files

- shp (stores feature geometry) - shx (stores index of features) - .dbf (stores attribute data) - .prj (projection data) - .xml (metadata) - .sbn and .sbx (stores additional indices)

What are Types of Thematic Maps?

-Dot Density MAP, Choropleth Map (Graduated Colors), Proportional Symbol MAP (Graduated Symbol), lsarithmic Maps, flow Maps, Cartograms

What are mental maps?

-Maps That exist only in our minds -does not reflect geographic reality but What is Our perception of the Location

When atom goes from one energy state to lower one, it emits an electromagnetic wave of characteristic frequency...

...known as "resonant frequency"

Survey Grade

0.1m $20,000

What are the four types of projected coordinate systems?

1. Conformal (true shapes) 2. Equal Area 3. Equidistant (true distances) 4. True Direction

In Situ Data Collection. Name the five methods used as source for GIS data.

1. Digitization of Historical Spatial Information 2. Global Positional System (GPS) 3. Traditional Land Surveying 4. Surveying Using a Total Station 5. In Situ Data Sampling or the Taking of a Census

How GPS works in five logical steps...

1. The basis of GPS is triangulation from satellites 2. GPS receiver measures distance (range) from satellite using the travel time of radio signals 3. To measure travel time, GPS needs very accurate timing (atomic clocks) 4. Along with distance, you need to know exactly where the satellites are in space. Satellite location. High orbits and careful monitoring are the secret 5. You must correct for any delays the signal experiences as it travels through the atmosphere (positional uncertainty)

How many characters can dBase field names contain?

10 Characters

In Selective Availability what is the distance in horizontal and vertical?

100m in horizontal and 160m in vertical

Return interval of each satellite

12 hour

How many orbital planes are the satellites on track of? How many on each?

6 orbital planes each containing 4 satellites

What is Hue?

A Basic Color such as Red, Blue, Green

Theodolite with an electronic distance measurement device, that can be used for leveling when set at the horizontal plane

A Total Station

"ultimate reference point."

A central location was chosen where the spheroid meets the earth: this point was intensively measured using pendulums, magnetometers, sextants, etc. to try to determine its precise location

Ratio Data

Data values measure a continuous phenomenon with a natural zero point Examples are rainfall and population

What is GIS?

A geographic information system (GIS) is a tool for making and using spatial information.

Planar Coordinate System

A planar coordinate system is defined by a pair of orthogonal (x,y) axes drawn through an origin

How does a projection start?

A projection starts with one of the three representations of Earth's irregular surface 1. Spheroid 2. Ellipsoid 3. Geoid

Display colormap image

A set of values is arbitrarily coded to match a defined set of red green blue values.

What are Maps built from?

Data. Shapes includes the geometry of the feature and where it is located on earth

Vertical Earth Datums

A vertical datum defines elevation, z

Where can one create a new feature class?

ArcCatalog. Then you can add spatial reference system. New fields

Coverage attribute table

Area and Perimeter

Conformal

At any point on the map the scale is same in every direction (USGS, 2011). Meridian and parallels interest at right angles

Oscillations of Atoms principle behind atomic clocks...

Atoms absorb or emit electomagnetic energy in discrete amounts that correspond to differences in energy between different configurations of the atoms.

What does each cell contain in a Raster Data Model?

Attribute value and location coordinates

Electromagnetic Spectrum

Bands often represent a portion of the spectrum. Ranges that vary from not visible to eye - the infrared or ultraviolet sections of the spectrum

How Can you differentiate graphic features?

By Using Opposite Colors

How Can you Normalize data?

By dividing one numeric attribute by another in order to minimize differences in values bused on The Size of areas or number of features in each area

How can you differentiate one graphic feature nicely?

By using colors that are equally Spaced

Limitations of Globes

Can we use globe in our hiking trip?

Three dimensional surface from which latitude, longitude and elevation are calculated

Datum

COMPASS

China. Initiated in 2000. being deployed. 35 by 2020.

Problems with Aerial Photography

Clouds, haze, shadows/sun angle, snow • Distortion - tip & tilt - relief distortion - radial distortion • Limited to 0.3 - 0.9 um (UV-NIR) • Storage and handling can be a problem

What are Three Geographic Data Models?

Conceptual Model- Set of Concepts That describe A Subject Mathematical Model- Model expressed in Symbols and equations Data Model - A Conceptual Model exp in A data structure

Isarithmic MAP

Contour Maps Maps continuous variables Uses lines Called isolines to connect places of equal quantity of The Variables Environmental Variables such as air quality, Temp, Precipitation, are considered Continuous (isotherms, isobaths. isohyets)

What are two file formats for Georelational Vector Data Model

Coverage Shape 'file'

Add Editor toolbar

Customize, Toolbars, Editor toolbar

WHAT term did The NSF Blue-ribbon Panel Introduce

Cyber Infrastructure

What were the Three Terms That were for This emerging field:

Cyberinfrastructure (Spatial CI), CyberGis, geographic information Science (Giscience) and Lately Spatial Information Systems

What are Event files?

Data table that includes map coordinates, such as latitude and longitude or projected coordinates

Nominal Data

Data values are categorized and have names. Data Value is an arbitrary type code. Examples are soil types and land use

Ordinal Data

Data values are categorized, have names, and the value is a numerical rank. Example is land sustainability classifications and soil drainage rank.

What does Vector Data Represent?

Discrete Features. Points. Lines. Polygons

Galileo Position System

EU and European Space Agency. Initiated 2005. Deployed. 18-24 satellites as of 2014

Monochrome image

Each cell has a value of 0 or 1. Often used for scanning maps with simple linework such as parcel maps which I have no idea what they are but I am very curious about but I am kind of stressed out about my four other exams so I couldn't really google it but I had the time to type all of this out. The last sentence was a run on sentence -10 points. College, huh? Go to college they said. Best four years of your life they said.

What is the Spaghetti Data Model?

Early vector data model to organize and manipulate line data.

Start editing

Editor, Start editing

Salaries GIS Scientists

Employment (2008) 209,000 and Growth By 72,600 with Expected Growth Rate By A to 13

Dichromatic Color Scale

Exception To The Typical Mono Scale. This is A Combo of two Mono Scales with a low color value in Center. Uses Natural midpoint which is a zero

Converting the image to a paper or other hardcopy form would not likely introduce error

False. Converting the image to a paper or other hardcopy form would likely introduce error (advantage of heads up digitizing)

GPS receivers are composed of an antenna, a central processing unit and a relatively inexpensive carbon infused metallic colored clock

False. GPS receivers are composed of an antenna, a central processing unit and a relatively inexpensive clock

Laser range finder can be accurate to a few millimeters at 10,000 m

False. Laser range finder can be accurate to a few millimeters at 1,000 m

Longitudinal strips extend from 90 degrees South latitude to 94 degrees North latitude.

False. Longitudinal strips extend from 80 degrees South latitude to 84 degrees North latitude.

Positions based on carrier signal measurements (L1, L2, and L5) frequencies are more less accurate than those based on the code

False. Positions based on carrier signal measurements (L1, L2, and L5) frequencies are *more* accurate than those based on the code

Snapping does occur if the nodes and/or lines are separated by more than the snap tolerance

False. Snapping does NOT occur if the nodes and/or lines are separated by more than the snap tolerance

on-screen digitizing may NOT be used to limit operator-induced positional error when digitizing.

False. on-screen digitizing may be used to limit operator-induced positional error when digitizing.

Along with distance, you don't need to know exactly where the satellites are in space. Satellite location. High orbits and careful monitoring are the secret

False. Along with distance, you need to know exactly where the satellites are in space. Satellite location. High orbits and careful monitoring are the secret

To measure travel time, GPS doesn't very accurate timing (atomic clocks)

False. It needs them

....satellites required to solve for x, y, z, and t

Four

Growth In GIS Related Markets

GIS(9.60), Gnss Base(22%), LIDAR(16.64), Gis Market in BFSI(4.95), Utilities(10.37), farming(13.36)

L1 (1573.42 MHz) and L2 (1227.6 MHz)

GPS satellites broadcast two carrier signals

GSDI

Global Spatial Data Infrastructure Association (GSDI)was established to coordinate collection and processing of GIS data worldwide

Disadvantages of OpenStreetMap

Good source of data but for some areas quality documentation and uniformity may be lacking

Why Do GIS?

Government decisions are based around geography. $270 Billion Market in 2013 Six New Occupations

Choropleth Map

Graduated Colors Shows rate, percentages of ratio or phenomenon Each geographic unit recieves A color pattern Color coded polygon Maps Uses monochromatic Scales or saturated colors

Proportional Symbol Map

Graduated Symbol Shows relative or absolute size of the entity to be mapped or number of particular phenomenon Located at that point if you want to show relative amounts, sizes or degrees of importance at specific Location

Graphic Scale

Graphic Representation of A map Scale Places A line on the map with ground dist marked such as 10,15 miles

WHAT IS GRACE?

Gravity Recovery and Climate Experiment

An imaginary circle drawn in any direction around the Earth's surface and whose plane passes through the center of Earth

Great Circles

Associated with plant photosynthetic activity, biomass, fractional cover of vegetation

Greenness

measure hundreds of wavelength bands

Hyperspectral - "HyMap" airplane sensor has 126 bands - Ocean Optics has thousands of bands

Incident Light

I = R + A + T I, R, A, and T are usually written as energy per unit time

Equal Area

If every part of the map , as well as the whole, has the same area as the corresponding part on the Earth, at the same reduced scale.

Information Presenetation (Remote Sensing)

Image Metadata (sources and processing lineage) Accuracy Assessment (Geometric, Thematic, Change detection) Analog and Digital Stats and Graphs

What is a Raster Model?

Implementation of field conceptual models. Array of cells that represents objects.

Data Collection (Remote Sensing)

In Situ Measurements (field (GPS), LAB (reflectance)) Collateral Data (Digital elevation model's, Soils, geology, population) Remote Sensing

What did They Realise About The future

In The future Science and Engineering will focus Heavily on huge datasets and will need digital data, grid's AND Software tools

Selective Availability

Intentional degradation of GPS accuracy

...the satellite signal slows as it passes through the atmosphere. The GPS system uses a built-in model that calculates an average amount of delay to partially correct for this type of error. Any error due to this is usually negligible

Ionospheric and Atmospheric Delay

What is Vector Point Feature?

It is a point layer which is a collection of records with (x,y) coordinates

What Are Atoms of Geographic Information?

It's An Infinite number anol We Can give A two Word description of every Sq km On The planet, 10 GB 1 number = Every Sqkm = I Pb (trillion Bytes)

QZSS.

Japan. 2002 initiation. Being deployed. 1st satellite in 2010

What codes do L1 and L2 carry?

L1 carries both C/A and P code L2 carries only P code

Spatial Questions Asked by GIS

Law Enforcement, Developer, University admissions, Aid worker, Realtor, Delivery Truck, Legislator, CDC

Light Vs DARK Colors

Light = Low Values DARK Colors = High Values Human eye 😲 Dark Colors

What are the two systems associated with Network Data Model?

Linear Referencing System Dynamic Segmentation

Increasing Interval Width

Long Tailed distributions 0-15, 5-15, 15-35

What are MXD files?

MXD files are Project files Saves your Layout, Preferences, Data not included, . mxd extension

Thematic Mapping

Map Types = Mental and Tangible Tangible = Reference and Thematic and Virtual Thematic = Qualitative and Quantitative Quantitative = Single Variable and Multi-Variable

When was Selective Availability turned off?

May 2, 2000

What Scale Would 1:100,000 be Considered?

Medium Scale

What is A DATA Model?

Method Used to represent real world objects

Active Remote Sensing

Microwave (RADAR) Laser (LIDAR) Acoustic (SONAR) Illumination provided by the sensor system (light or radiowaves)

GLONASS

Mother Russia. Initiated 1976. Restoration. 23-24 satellites in 2011

measure several wavelength bands

Multispectral - Average reflectance in the bands - Landsat TM-7 had 7 bands - NDVI: bands 3 (red) and 4 (NIR)

USGS Topo maps are...

NAD27

if you are in N. America, and want to match your... topo maps

NAD27

if you are in N. America, and are collecting raw data...

NAD83

...takes advantage of the ability of vegetation to strongly reflect near-IR and poorly reflect red, resulting in a high contrast between bands and a high...

NDVI

NDVI FORMULA

NDVI = (NIR - RED)/(NIR+RED)

Is making geographic data more accessible to the public by reducing duplications, improve quality and reduce costs

National Spatial Data Infrastructure (NSDI)

What is a Network Data Model?

Network topological relationships define how lines connect with each other at nodes and define rules about how flows can move through the network

Can Representations be Accurate all The Time?

No Representations Can be deceiving.

Can geometric characteristics of features that have topology be changed?

No. Even when the data maybe altered through projection and data transformation

NDVI

Normalized Difference Vegetation Index

what Are Objects?

Objects Are Well defined boundaries in An empty Space. Example could be the 49 Houses in A Subdivision

The Geographic Coordinate System

Once you have a ellipsoid, you also define the location of poles (axis points of revolution) and equator (midway circle between poles, spanning the widest dimension of the spheroid), - You have enough information to create a coordinate grid or "graticule" for referencing the position of features on the spheroid.

Variables In Thematic Maps

One Variable = univariate maps Two Variables = bivariate Maps

What are the four types of Database Relationships?

One to one One to many Many to one Many to many

Extended Raster

One value per cell but multiple attributes per value in value attribute table (VAT) --> what does this mean? In the VAT table there is a limestone which has the value of 1 but there are 7 Limestones in total in the Raster Data Model.

An effort to develop global data through international volunteer collaboration

OpenStreetMap

CLASH

Opposites

....these are inaccuracies of the satellite's reported location. Any error due to this is usually negligible.

Orbital errors: AKA ephemeris errors

Digital imagery in which distortion from the camera angle and topography have been removed, thus equalizing the distances represented on the image

Orthophotography

French scientists suggested earth was flattened at equatorial regions

Oui. Vrai. True.

What does Vector topology help with?

Overshoots Slivers Dangles Not Sharing borders

Passive Remote Sensing

Panchromatic Multispectral Hyperspectral • Illumination typically by the sun • Passive - no energy provided by the remote sensing system to the object example the moon or the earth from space

What are the two types of Remote Sensing?

Passive Active

What are some components of a Vector Model?

Point, line, and polygon representations. Used in Cartography and network analysis.

Exponential Scale

Popular method of Increasing intervals Break values That Are Power of 2n and 3n mostly Start W/T Zero 0, 1-2, 3-4, 5-8, 9-16

Describes sensitivity of receiver to changes in the geometric positioning of the GPS satellites

Position Dilution of Precision (PDOP)

This is the ratio of the volume of a tetrahedron created by four observed satellites to the volume defined by ideal tetrahedron

Position Dilution of Precision (PDOP)

(PDOP)

Positional Dilution of Precision Satellite position/geometry. - Describes sensitivity of receiver to changes in the geometric positioning of the GPS satellites - This is the ratio of the volume of a tetrahedron created by four observed satellites to the volume defined by ideal tetrahedron

What is A Color wheel?

Provides Guidance in choosing Colors

Quantitative Vs Qualitative thematic Maps

Qualitative maps are nominal which means It's Textual and not numerical Quantitative maps are numerical meaning The data is in numbers and was measured

Range formula

Range = speed of light X travel time

What does Raster Data form?

Raster Data forms a grid of cells or pixels

Diagrams of Raster and Vector data

Raster data is described by A Cell grid, one Value per cell

- Clocks similar to quartz watch - Always an error between satellite and receiver clocks ( t)

Receiver Clocks

.....A GPS receiver's built-in clock is not as accurate as the atomic clocks onboard the GPS satellites. Leads to slight timing errors. Any error due to this is usually negligible.

Receiver clock errors

Name three types of GPS Units

Recreational Grade Mapping Grade Survey Grade

Red-Green-Blue Composite

Red in the top half Green the Left half Blue in the bottom half

- 2 Cesium & 2 Rubidium in each GPS satellite - $100,000-$500,000 each

Satellite Clocks

Raster data Model

Regular grid of Cells Each Cell represents an area on the ground Spatial Resolution, Value assigned to cell represent reflectance, land Cover, Elevation Sateillite images, DE-M, and They are good for continuously changing attributes

measures electromagnetic energy reflected or emitted from objects - airborne or satellite based instruments

Remote Sensing

Dot Density MAP

Show Variation in Spatial density of Some Phenomenon. Used To plot The Absolute number of things. Thematic Maps Can be Used To plot one or more Specific Variables.

Equidisdant

Show true distances along center of the projection or along a special set of lines

Flow Maps

Shows Volume and directions of The movements of Something Such as population or commodities

Pythagoras and Aristotle reasoned the Earth was a sphere

Si. Yes. True.

...this occurs when the GPS signal is reflected off objects such as tall buildings or large rock surfaces before it reaches the receiver. This increases the travel time of the signal, thereby causing error

Signal multi-path

Instruments and Procedures used for millenia i.e. Egypt, Cyclopedia

Simple plane-table instruments and procedures

Takes nodes and snaps them to a nearby line, if the nearby line is within a specified tolerance

Snapping (lines)

Snaps nodes to nearby nodes within a tolerance.

Snapping (nodes)

Sources of Signal Interference

Solid Structure Electromagnetic fields

In a Raster Data Model what does spatial data model define?

Space as an array of equally sized cells arranged in rows and columns, and composed of single or multiple bands.

Dynamic segmentation

Special case of linear referencing in which data values are added dynamically to the route each time the user queries the database

How are stations measured in a triangulation survey network?

Stations may be measured using astronomical (open circles) or surface surveys (filled circles)

What is a geodatabase?

Store for all types of geospatial information

Starting points need to be very central relative to landmass being measured

Surface Based Datums

Prior to satellites, datums were realized by connected series of ground-measured survey monuments

Surface-Based Datums

What do Layer files Save?

Symbology and Setting Used to Saving Legend Setting extension is .|yr

WAAS needs unobstructed view of the horizon!

TRUE

A Quartile is A distribution That Seperates in to equal Sizes of feature Attribute

TRUE. 0-25, 25-50, 50-75

Requires a person to enter coordinate information through the use of a digitizing tablet and digitizing puck

Tablet Digitizing Answer is literally in the question. Kind of.

The United States Geological Survey (USGS) has combined data from 20 federal agencies and created a base map at a single portal

The National Atlas

This is described as "cornerstone" of U.S. mapping efforts

The U. S. National Map

What is the difference between the ellipsoidal and Geoidal height?

The difference between the ellipsoidal height and geoidal height at any location is less than 100 meters over most of the Earth

Define Contrast

The greater the difference in value between an object and its background is greater The Contrast

DOQQ image resolutions

The ground length of one pixel of the image - image with one meter resolution means that each pixel in the image represents one square meter on the ground.

How do you convert to Degrees from Degrees: Minutes: Seconds?

The latitude and longitude are input in degrees, so you might need to convert to decimal degrees from degrees: minutes: seconds EXAMPLE: 65:45:36 south latitude converts to -(65 degrees + 45 minutes x (1 degree/60 minutes) + 36 seconds x (1 minute/60 seconds) x (1 degree/60 minutes) = -65.76 degrees latitude

Linear Referencing Systems

The locations of geographic entities are stored as distances along a network from a point of origin

In most cases preserving one of these spatial properties of the data decreases accuracy of the other properties (projected coordinate system)

True

Define Map Projections

The transformation of a curved Earth to a flat map.

Digitizing the map (Heads Up)

The user can zoom to specific areas on screen and trace points, lines, or polygons on the map. Because the maps are already in the correct geographic coordinate system anything digitized on top of the map will also be in the correct coordinate system.

Route topology

The way that a line feature of one type (e.g. commuter rail line) shares segments with line features of another type (e.g. Amtrack rail line)

Arc-node and node topology

The way that line features connect to point features

Regions topology

The way that polygons overlap (e.g. GIS layers with a time component) or when spatially separate polygons are part of the same feature

Is a geometric deformation indicator. A small circle on the surface of Earth projected as a small ellipse on a map projection plane.

Tissot's Indicatrix

TIGER

Topologically Integrated Geographic Encoding and Referencing files

EarthCube Vision

Transform The Conoluct of Geosciences Reasearch. Predict Earth System from center of The sun to the Center of Earth Earth Cube integration of geosciences data, information, Knowledge. and Tools

Name Some Data Types.

Triangulated Irregular Network, Annotation, Multipatch

1:5,000 is A Large Scale

True

1:50,000,000 is A Small Scale

True

A CAD system is real-world entities are represented symbolically as simple point, polyline, and polygon vectors

True

A Vector Model is an implementation of discrete object conceptual model

True

A cartesian coordinate system is one that assigns two coordinates (x & y) to every point on a flat surface.

True

A conventional total station needs local or federal control points

True

A projected coordinate system is always based on a geographic coordinate system that is based on a sphere or spheroid.

True

A raster can have one or many bands

True

All satellites transmit same signal "string" at same tim

True

An advantage of heads up digitizing is many data sources are inherently digital, these data may be magnified on screen to any desired scale

True

Another OpenStreetMap drawback, method of distribution data is available in publicly defined but rarely used format, and a 3rd party sales the data in standard format

True

As plants grow, canopy and biomass increase

True

Atom Clock came into being during World War II; nothing to do with GPS. Physicists wanted to test Einstein's ideas about gravity and time

True

Babylonians believed the Earth was flat disk floating in an endless ocean

True

Can DATA frames be Used for Context?

True

Carrier signals are modulated to produce coded signals C/A code at 1.023 MHz and the P code at 10.23 MHz

True

Datum allows us to figure out where things actually are on the graticule since the graticule only gives us a framework for measuring, and not the actual locations

True

Datum is a frame of reference for placing specific locations at specific points on the spheroid

True

Digitizing software allows a user to collect data in point mode or stream mode.

True

Einstein predicted that clock on Mt. Everest would run 30 millionths of a second faster than clock at sea level

True

Elevation is typically defined as the distance above a geoid.

True

French Royal Academy of sciences between 1730-1745 measured the shape of earth near Equator in South America and in high northern latitudes in Europe

True

GPS clocks are cesium clocks

True

GPS receiver measures distance (range) from satellite using the travel time of radio signals

True

GRID's are a raster data format

True

Geoid is always at right angles to the direction of local gravity, and this surface is the reference against which heights are measured

True

Global data sets are less common than national data set

True

Green leaves absorb more red and blue light

True

Groups of cells that share the same value represent the same type of geographic feature.

True

Heights above an ellipsoid are often referred to as ellipsoidal height.

True

Horizontal Earth Datums. An earth datum is defined by an ellipse and an axis of rotation

True

Ideally plane-table was placed directly over a monument that had x, y, z coordinates.

True

In GCS, Each degree of latitude represents about 110 km, although, that varies slightly because the Earth is not a perfect sphere

True

In GPS Standardization it is better to use UTM coordinates than Latitude and Longitude

True

In Line (Arc) Feature each point has a unique location

True

In Polygon feature line segments bound the feature.

True

In Polygon feature the first and last coordinates pairs are in the same location

True

In a projected coordinate system, locations are identified by x,y coordinates on a grid, with the origin at the center of the grid.

True

In order to use the Vector Data in ArcMap, the coordinate system for the data must be identified

True

What are UTM's used in?

USGS topographic map, and digital elevation models (DEMs)

Conformal projection, so small features appear with the correct shape and scale is the same in all directions. (all distances, directions, shapes, and areas are reasonably accurate ).

Universal Transverse Mercator (UTM)

Map Ratios

Use of with any Linear measurement Unit Such as ft. miles, meters Example: 1:24,000 Which means I inch on The map is 24,000 inches on The ground

Three segments of GPS

User Satellite Control

Surface Based Datums were largely done without having to measure distances. How?

Using high-quality celestial observations and distance measurements for the first two observations, could then use trigonometry to determine distances

Registering the map (Heads Up)

Using the same transformation methods previously discussed, the user can enter control points on screen and transform the scanned image to real world coordinates.

25 ground reference stations positioned across the U.S. Send data to 2 master stations

Wide Area Augmentation System (WAAS)

Point mode

allows the operator to place discreet points to represent geographic objects. This is the method you are probably most familiar with

Stream mode

automatically places points at specified time intervals, and the user traces the digitizing puck along the geographic features.

Resonant frequencies are identical for every atom of a given type...

cesium 133 atoms: 9,192,631,770 cycles/second

Two satellites the receiver is somewhere on a....

circle where two spheres meet

Why is choosing the right projection important?

controlling distortions

Reflectance

defined as the ratio of reflected light to incident light p=R/I

Transmittance

defined as the ratio of transmitted light to incident light t=T/I

Grayscale Image

each cell has a value of 0 to 225. Used for black and white aerial photographs

Add new feature class

example would be streets.

Flattening Ratio Formula

f = (a-b)/a

Ellipsoidal Height formula

h = H + N h = ellipsoidal height H = orthometric height N = geoidal height

What two things are needed for a Datum?

spheroid and set of surveyed and measured points

Problems with Infinite Complexity

many Limiting details, User must make A choice, Devs must allow for many options Important Question is what we Choose to Think About The World

What is taken into account in a Vertical Earth Datum?

map of gravity anomalies between the ellipsoid and the geoid

What is topology?

mathematical study of the properties of objects.

Is the The Spherical Model accurate?

model is very inaccurate and should only be used for scales smaller than 1:5,000,000,000.

Three satellites the receiver is at...

one of two points where the three spheres intersect

Four satellites the receiver is at...

one point where the spheres intersect

When digital data for a GIS project is not available, it is created from....

paper maps

Early twentieth century Bridseye and Clarke from USGS, used ____________ in western USA

plane-table surveying

C/A, P and M are commonly referred as...

pseudo-random code

Specialized software is used to convert the scanned image into lines. This process is called....

raster to vector conversion (R2V)

Absorbtance

ratio of absorbed light to incident light a=A/I

Receivers decodes each signal from GPS satellite to identify...

satellite, transmission time and satellite position at the time the signal was sent

HIGH PDOP...

satellites close together. Large area of uncertainty

LOW PDOP...

satellites widely spaced small area of uncertainty

What do Datum's define?

the origin and orientation of latitude and longitude lines.

Define Geodesy

the science of measuring the shape of the Earth

NAD83

uses the GRS80 ellipsoid on a geocentric axis of rotation

Define Map Projection

the transformation of a curved Earth to a flat map

Polygon topology

the way that neighboring polygons connect and share borders

Receivers have nanosecond accuracy (0.000000001 second)

true

the Greenwich Meridian is the origin of the X axis and the Equator is the origin of the Y axis

true

How did Eratosthenes measure the circumference of the earth?

used a deep well in Syene, Egypt and vertical post at Alexandria at an angle 7 12' and found circumference of Earth, 40, 250 km, he was off by 4%, 38,762 KM

How Can We Limit The Detail On Maps?

we Can aggregate, generalize, approximate. Can We ignore The water? But That is 2/3 of The map. You Can give one Temperature To Houston for ex. Sample The Space As do measurements only in Weather stations in Weather stations. Nearly All geographic data miss detail.

How many satellites orbit the Earth? And at what speed?

~31-32 satellites, orbit the Earth at 20, 200 km\12,600 mi

Where and what do the two master stations do in regards to WAAS?

• 2 master stations (on west and east coasts) - Accounts for satellite orbit, clock drift, and signal delays - Sends corrections to geo-synchronous equatorial satellites, which is received by your GPS unit

Smart Station Procedure

• A SmartStation uses a GPS-enabled station that uses dual frequency GNSS receivers and real-time kinematics (RTK) technology. • A SmartPole is a GPS enabled stadia rod. Both SmartStation and SmartPole can be used independently to acquire accurate x, y, z, measurements • A surveyor will setup the SmartStation at a location that has unobstructed view of the sky. The surveyor then takes the SmartPole and walks to important locations in the terrain to obtain measurements *make sure to look at image in lecture explaining this process*

Explain Datum's in every way possible.

• A datum is essentially the model that is used to translate a spheroid into locations on the earth • A spheroid only gives you a shape—a datum gives you locations of specific places on that shape. • Hence, a different datum is generally used for each spheroid

Five steps involved in Digitizing new features

• Create base map • Add feature in ArcMap • Start editing (Editor toolbar) • Digitize feature • Stop editing and save

What are the two types of Coordinate Systems?

• Geographic coordinates (Φ, h, z) Latitude and Longitude. • Projected coordinates (x, y, z) on a local area of the earth's surface

Explain the procedure involved in Traditional Land Surveying

• Ideally plane-table was placed directly over a monument that had x, y, z coordinates. • Surveyors repeated this procedure at second stations and measured the distance between stations • As second member of the surveying crew would go to a station 3 and hold a leveling rod (stadia), the surveyor at home station could view the stadia through alidade and determine the change in elevation

Certain features of a Geographic Coordinate System

• Like a planar coordinate system, with an origin at the point where the equator meets the prime meridian • The difference is that it is not a Grid because grid lines must meet at right angles; this is why it's called a graticule instead

What are the four sources to get Soil Data?

• Natural Resources Conservation Service (NRCS) • National Cartography and Geospatial Center (NCGC) • State Soil Geographic Database-STASGO • Soil Survey Geographic Database- SURGO

What are Representations?

• Needed To Convey Information ° fit Info into a standard form or model • Simplify Representation

Ways of Measuring Spectral Reflectance

• Optical Spectrometer • Non-imaging - Just spectrum • Ground-based, aircraft, or satellite • Example: Ocean Optics Spectrometer - 350 to 1,000 nm

Four Basic Functions of GPS

• Position and coordinates. • The distance and direction between any two waypoints, or a position and a waypoint. • Travel progress reports. • Accurate time measurement.

What are some Analysis Examples?

• Predict fate of pollutants in the atmosphere • The spread of disease • Animal migrations • Crop yields • EPA - hazard analysis of urban superfund sites • Local to global scale forest growth analysis

- Incorporates the L2 satellite signal real-time - Need special DGPS equipment

• Real-time DGPS

Two types of Differential GPS (DGPS)

• Real-time DGPS • Post-processed DGPS

NHDPlus Reach Attributes

• Slope • Elevation • Mean annual flow - Corresponding velocity • Drainage area • % of upstream drainage area in different land uses • Stream order

Name three methods of Digitizing.

• Tablet Digitizing • Heads-up Digitizing • Scanning and Vectorization

Steps for heads down digitizing

• Tape map to the digitizer • Register control points on the map • Estimate two conversion equations (one for vertical and one for horizontal coordinates) • Digitize vectors (points, lines, or polygons)

Applications of GPS

• To determine exact location • Routing • Navigation • Finding Places • Precision agriculture • Geotaging • Crowd sourcing • Geological

Types of Air Photos

• Vertical • High Oblique (horizon) & Low Oblique (no horizon) • Stereo/3D

Differential Correction Procedures

• WAAS (can improve to 2-5m) • DGPS (can improve to 0.1-1m) • Real-Time Differential Positioning • Real Time Kinematic and Virtual Reference Stations

Where do Representations occur?

• We get Info Through Our senses and Store it in our minds • In photographs, 2-dimensional models of Light received by the camera • In Text, Info is in words

Aerial Photographs

• common • relatively inexpensive • easy to interpret • small area coverage • can be geometrically corrected

Non-visible boundaries in TIGER?

• county, city, neighborhood boundary • property line

What features are included in TIGER?

• roads and street centerlines • railroads • rivers • lakes • census statistical boundaries