SSCI Midterm
orbit the Earth
*almost perfect circle *elliptical ( ) with 4 seasons of equal length
The Elite 8
- Frame line and neat line - mapped area - insets - title/subtitle - legend - data source/author - scale - orientation
Low Earth Orbits
- Frequent periodic revisits of a given area - Worldwide access possible - short dwell time over any given target
High elliptical orbit
- Great polar access - long dwell time over the northern hemisphere - very limited southern hemisphere access
GPS uses
- Originally used by the military - Measuring earthquake epicenters - Civilian usage for navigation (allowed in 1995 when Clinton declassified it)
Geosynchronous Orbits
- Wide area access - Continuous coverage area - limited to no polar area coverage
methods of geographic measurement
- area, distance, direction, shape
why do we care about projections?
- different projections cause different appearances, our mapped data looks different, it can confuse the audience
Mercator Projection
- rectangle used for areas - most popular projection, standard map projection - preserves direction and shape UTM is a projection that was adapted from the mercator projection UTM is the mercator projection with grids
Vector Data
- vector data consists of individual points made up of points, lines, and polygons - points are used when features are too small to be represented as polygons - lines connect each vertex with paths A format for storing location-based data in a geographic information system that uses latitude and longitude coordinates to represent geographic features with points, lines, and other complex shapes. - has attributes ex polygons for lakes, buildings for points, paths for roads etc I would do temperature or elevation as raster
Isolines (contour lines)
-A contour line is a line that passes through points having the same elevation. It connects points of the same value. -The distribution of the lines shows how values change across a surface. -Adjacent contours indicates the gradation of values. -Points, raster, triangulated irregular network (TIN), or terrain dataset surface can create contour lines.
Hierarchies
-A system of ordering things according to the level of importance -Classification of living organisms is a hierarchy. -Depicting them can be easy if they are spatially nested. Other examples? -It gets complicated if they are not nested. Examples?
what do projections do
-Define relationship between points on the graticule and points on a flat map. -Define the relationship mathematically. -Cause distortion in some combination of four methods of geographic measurement. theres distance direction shape and area so something will be distorted no matter what you use
3 key points about gps
-Initially, GPS changed the way U.S. and Allied Forces fight. -Additionally, GPS fulfilled many civil and commercial uses. -Accordingly, GPS must change to meet the needs of the future.
State Plane Coordinate System
-It was developed in the 1930s by the U.S. Coast and Geodetic Survey to provide a common reference system to surveyors and mappers. -There are a set of 124 zones. Each zone has its own central meridian or standard parallels to maintain the desired level of accuracy. -The boundaries of these zones follow county boundaries. Smaller states, such as --=Connecticut, require only one zone, while Alaska is composed of 10 zones.
Universal Transverse Mercator System
-One consistent system covers the world. -It is four times less accurate than typical State Plane Coordinate systems. -The North Atlantic Treaty Organization (NATO) played roles in its creation after World War II. -The goal was to design a consistent coordinate system that could promote cooperation between the military organizations of several nations. -Before the introduction of UTM, allies found that their differing systems hindered the synchronization of military operations
Shape of the Earth
-The circumference of the sphere is measured along a great circle on the sphere. Find the circumference of the Earth by finding the length of intercepted arc of a small central angle. -Find two places on the surface of the Earth that lie on the same meridian (or close to it): --Meridians are halves of great circles. -Eratosthenes chose Alexandria and Syene, near contemporary Aswan.
hierarchy
-The concept of hierarchy is important in the real world, in the virtual world, and in all worlds where the two interact. -Generally, a hierarchy is an ordered set of items arranged in a fashion where it is possible to state, with certainty, that any given item is "above," "below," or "at the same level as" any other element in the set.
fishnets vs hexagons
-The square (fishnet) grid is the predominantly used shape type in GIS analysis and thematic mapping as it matches the display format for most all display devices (e.g, monitor, screens, etc...) -Yet, there are cases in which hexagons may be better suited for the analysis being conducted.
Equal Interval
-Use equal interval to divide the range of attribute values into intervals, and the class breaks based on the value range are automatically determined. For example, if you specify four classes equal-sized subranges. This allows you to specify the number of for a data set whose values range from 0 to 120, four classes with ranges of 0-30, 31-60, 61-90, and 91-120 are created. -Equal interval is best applied to familiar data ranges, such as percentages, elevation, and temperature. This method emphasizes the amount of an attribute value relative to other values. For example, it shows that a shop is part of the group of shops that make up the top one-third of all sales.
GPS (global positioning system)
-a position (x,y) requires at least 3 satellites -height needs at least 4 satellites - the gps radio signal speed is 297,600 km/hr - canopy blocks the signals
DMS to Decimal Degrees
1 degree = 60 minutes 1 minute = 60 seconds 1 degree = 3600 seconds
spatial data quality parameters
1. Lineage 2. Completeness 3. Logical Consistency 4. Positional quality 5. Thematic quality 6. Temporal quality 7. Usage, purpose, constraints 8. Variation in quality 9. Meta-quality
3 ways for a plane and sphere to interact
1. No contact 2. tangent 3. plane intersects with the sphere, creating either a great or a small circle
spherical video camera
360-degree videos, also knownas immersive videos or spherical videos are video recordings where a view in every direction is recorded at the same time, shot using an omnidirectional camera or a collection of cameras. During playback on normal flat display the viewer has control of the viewing direction like a panorama. It can also be played on a displays or projectors arranged in a sphere or some part of a sphere.
-Oldest map -Known as Imago Mundi 6th c. B.C.E (Before the common Era)
6th century BCE Babylonian Map of the World
Bivariate colors
A bivariate map is a type of thematic map that displays two variables by using different colors and/or symbols. The variables in a bivariate map can be on the same layer or separate layers
Geodesy
A branch of mathematics dealing with the shape and area of the Earth
function vs relation
A function requires that each element of X be associated with only one element of Y (although many different elements of X may be associated with the same element of Y). A relation removes this restriction, allowing one element of X to be associated with many elements of Y. Thus, every function is a relation, but not every relation is a function
Large scale vs. small scale maps
A large scale map only shows a small area, but it shows it in great detail. A map depicting a large area, such as an entire country, is considered a small scale map
Raster data
A matrix of cells organized into rows and columns (a grid) where each cell contains a value. Cells have a set size, so you can't zoom in forever
Datum
A set of parameters linking an ellipsoid to the earth that helps define a coordinate system A theoretically exact point, axis, or plane derived from the true geometric counterpart of a specific datum feature. The origin from which the location, or geometric characteristic of a part feature, is established. how we fit geoids in ellipsoids
Accuracy vs Precision
Accuracy = closeness to the target, Precision = small range of data points
Advantages and disadvantages of Vector data
Advantages: - Can be scaled to any size and retain sharpness - Useful for geometric images Disadvantages: - More difficult to edit and model - data storage is more complicated - must be converted to raster to display electronically
Advantages and disadvantages of Raster data
Advantages: - Simple data structures - Location-specific manipulation of attribute data is easy - many kinds of spatial analysis and filtering can be used - Mathematical modeling is easy because all spatial entities have a simple, regular shape - Tech is cheap and many forms of data are available Disadvantages: - Large data volumes - using larger cells to decrease storage volume means lower resolution, less precise data, loss of information - crude raster maps are inelegant - coordinate transformations are difficult and time consuming unless the right tech is used, even then can lead to loss of info or distortion of grid shape
Military grid reference system
Another coordinate system. That's legit what's in my notes
Natural Breaks
BASED ON TRENDS With natural breaks classification (Jenks), classes are based on natural groupings inherent in the data. Class breaks are created in a way that best groups similar values together and maximizes the differences between classes. The features are divided into classes whose boundaries are set where there are relatively big differences in the data values. Natural breaks are data-specific classifications and not useful for comparing multiple maps built from different underlying information.
Modernizing GPS
Better support the warfighter in the evolving threat environment More signal power = more anti-jam More secure new military code structure More User Equipment anti-jam capability = more protection Better able to deny an enemy use of GPS Better support to civil GPS customers New civil signals for improved accuracy, integrity and continuity of service = robustness Compatibility with civil aviation and terrestrial naviagtion systems
Edge
Boundaries and breaks in continuity. Coastlines, rivers, cliffs, etc.
advantages of a graphic scale
Can be used for direct measurements on the map. Is true at whatever enlargement or reduction you use on the map. Can show different units, e.g. miles and kilometers. BUT...may be directionally biased.
Proximity
Can find proximity of Points, lines, or polygons, by extending an area outward from the original data. Can be used as 'buffers' to help find bisectors, partitioning, and to find Thiessen Polygons. Can be dissolved or not (not means that overlaps in buffer zones are noted).
Monitor Stations
Constantly collecting GPS data for all satellites in view Track satellites, collect data, feed it to master control station
vector data disadvantages
Continuous data is poorly stored and displayed Needs a lot of work and maintenance to ensure that it is accurate and reliable
London Cholera Outbreak Map
Created by Jon Snow in 1854. Snow mapped the locations of the cases in the recent Cholera outbreak, where he realized that they were clustered around water pumps. This led to the connection that Cholera was caused by contaminated water.
coordinate systems
Different Types- Geocentric(x,y,z)- Geodetic(DD,DM,DMS) - UTM- MGRS Different Formats Different Height Systems - (h)HeightaboveEllipsoid - (H)HeightaboveGeoid Different Horizontal Datums - WGS-84 - NAD27,NAD83
Field Data Collection
Differential Correction: A technique for increasing the accuracy of GPS measurements by comparing the readings to two receivers- one roving and the other fixed at a known location
Calculating the circumference of the Earth
Eratosthenes did it first, looked at the shadows of sticks in Alexandria and Syene on noon of the summer solstice, used that to calculate the angles of sunlight, used that and trig to figure out the angle of the intercepted arc he'd created, and used the actual distance between the cities to calculate the full circumference.
Geoid
Even more accurate version of the Earth's surface, dealing with surface irregularities. Generally not used for models because it's so complex and so it's very slow.
absolute location
Exact location of a place on the earth described by global coordinates 34.022279°, -118.282589° 669 w 34th St, Los Angeles, CA 90089 "I'll drop you a pin..."
Military Grid Reference System (MGRS)
Extension of UTM system. Zone number and zone character used to identify an area 6⁰ in E to W extent and 8⁰ in N to S extent - System uses set of alphabetic characters for the 100 km grid squares ex: 52S CG 00669 9075
reflection
Flipping a figure/point over an axis. Transformation
Home assignment #1 Mental Maps
For this assignment, the class was asked to make a map of either their hometown or the USC campus. It was inspired by Kevin Lynch and his work in The Image of The City. This text was innovative because it asked students to draw maps from memory. Using actual people instead of urban designers is beneficial because people may not always use the same paths that are designated by urban designers. They may create their own shortcuts. We were asked to use paths, edges, districts, nodes, and landmarks which are the "five key elements" according to Kevin Lynch. The goal that I would like to achieve is to test my knowledge of how well I know the Palisades village, my hometown, after living there for 20 years. During high school, I would usually walk most places in the village after school since I did not have a car and I have not usually had directional issues and I'd like to think that I have memorized the area well. My goal is to create an accurate map.
hw #5
For this assignment, we were instructed to look at a map of Extreme Temperatures for the United States during January and 2011 that was originally quite hard to comprehend without turning off every other section besides the one I wanted to see the temperatures for. The low temperatures for July 2011 and January 2011, and high temperatures for July 2011 and January 2011 were all marked with the exact same symbol, a red dot. The color red is correlated with heat and not being able to differentiate the symbols made it extremely difficult to tell which dots represented which time. This exercise exemplifies the importance of symbolization in maps and what makes a good map. Simplicity and readability are key and I got to create my own map where I tried to maximize its legibility. This type of map in particular could be used for weather forecasting and planning to gather resources for those who need shelter or water. My goal that I would like to achieve with this project is to make a map that considers all audiences and is as simple as possible so users can gather data as quickly as possible. Methods I gathered my data to find that in "July 2011 Low", the pattern was that the temperatures were located mostly on the coastline of the western side of the United States and Alaska. In "January 2011 Low", the temperatures were located across Alaska and the middle of the United states. In "July 2011 High", temperatures were located in California, Arizona, Oklahoma, and Kansas mostly. In "January 2011 High", the temperatures were located mostly in Los Angeles and Texas. I then analyzed which parts of the data or map were confusing and went through the symbols to find which were easiest to identify with heat and cold and switched out the red dots.
Elite 8 Map Elements
Frame line and neat line Mapped area Insets Title/subtitle Legend Data source / author Scale Orientation
Function vs Relation
Function = only 1 x for any number of Ys, Relation = any number of Xs and any number of Ys
Geospatial Analysis
Gathering, display, and manipulation of imagery, GPS and Satellite Photography, and historical data site projection, proximity, line of sight, pattern analysis, geospatial query, routing
GPS
Global Positioning System - the US GNSS system composed of 24 active satellites, ground control stations, and devices that interact with the system as receivers.
vector data advantages
Graphical output is generally more aesthetically-pleasing Higher geographic accuracy because data isn't dependent on grid size
Latitude
Horizontal lines that divide the globe from North to South pole, ranging from 90 degrees N to 90 degrees S
sources of errors (general data collection)
Humans: mistakes of measurement and of judgment, such as how to categorize an object Instruments: faulty readings; also, measurements can only be as precise as an instrument allows. The precision capability = resolution. Environment: situational factors affecting readings such as temperature, visibility, etc.
Quantile
In quantile classification, each class contains an equal number of features. A quantile classification is well suited to linearly distributed data. Quantile assigns the same number of data values to each class. There are no empty classes or classes with too few or too many values. Because features are grouped in equal numbers in each class using quantile classification, the resulting map can often be misleading. Similar features can be placed in adjacent classes, or features with widely different values can be put in the same class. You can minimize this distortion by increasing the number of classes.
Raster vs Vector
In raster data, a point feature is a single cell, no matter what the size. In raster data, a line is a series of cells that are not connected with direction, as in vector. In raster data, the spatial relationships are implicit in the grid, and therefore each cell does not have coordinates associated with it.
Hw #4ArcGIS Online and Story Maps
Introduction: I was instructed to create my own app on Arcgis online and explore story maps. I created a map of Houston, Texas with evacuation routes and demographic data by census tracts. The census tracts were symbolized based on the percentage of the population without a vehicle. I used this map to then create an app where users could press on different areas of the map to see pop ups about percentages of households without vehicles in the given area. Lastly, we were instructed to find a story map that interested us. Methods: To create the map, I followed the tutorial on Arcgis. First, I found Houston on the map and added a layer for evacuation routes. Next I changed the base map so the evacuation routes would be easier to see. Next I added bookmarks. After that I changed the styles of the evacuation routes. Next, I added demographic information. I added the field "Percent of Households without a Vehicle" to symbolize the tracts with different colors based on households without a vehicle. Next, I created an app. Lastly, I saved and published my app. Next, I looked through the story maps and chose a maple syrup festival map in Canada.
Mental Maps
It shows we understand the geographical world. It is a way to combine our objective knowledge of places in addition to our subjective perceptions (opinions) of locations. People have different perceptions of the same place. Cultural studies, psychology, sociology, and geography study to understand how humans look at the world around them and process that information, internally and externally.
raster data disadvantages
Linear features and paths are difficult to display Subject to a pixelated look and feel Datasets can become very large because they record values for each cell
ways to measure absolute location
Local Survey (e.g., Building Architecture/Construction) Street Addressing System State Plane Coordinate System Universal Transverse Mercator System Public Land Survey System Military Grid Reference System
raster data advantages
Map Algebra with raster data is usually quick and easy to perform Some specific use cases can only be achieved with raster data (e.g. modeling water flow over the land surface)
map scale
Map scale refers to the relationship (or ratio) between distance on a map and the corresponding distance on the ground. For example, on a 1:100,000 scale map, 1 cm on the map equals 1 km on the ground.
how do we choose a projection
Map type: world literacy rates purpose: show the spatial distribution of world literacy step 1: determine what type of distortion to minimize. step 2: determine the geographic extent. What projections are good at showing our geographic extent? step 3: determine what part of the world are we mapping equator, mid latitudes, or polar regions step 4: determine the best projection for the shape of our geographic area
Ellipsoid
More accurate shape of the Earth, accounting for equatorial difference
Translation
Moving the figure, not changing anything else (size, orientation, etc) but just pushing it around. transformation
is one to many a function?
No
Can you use the state plane coordinate system to study Spain
No because it is only an AMERICAN system
postal transformation
One physical letter to one physical address Many physical letters to one physical address Same letter cannot go to many physical addresses
Antipodal points
Points that are opposite of each other on the Earth. Line between the points passes through the center of the Earth. Calculate antipodal point of (X,Y): Lat = -Y, Long = 180-X if you get directions, then you swap north for south or east for west instead of doing a negative or positive sign latitude is always Y
Vector Data
Points, lines, or polygons. Infinitely scalable
Thiessen Polygons
Polygons created from point data that measure proximity to the nearest point until they run into another proximity, creating cell-like structures of shapes.
Kaarta
RAPID AND ACCURATE MOBILE 3D SCAN TECHNOLOGY: A FAST TRACK FROM CAPTURE TO ANSWER
Raster Data
RASTER IS FASTER BUT VECTOR IS CORRECTOR - CONTINUOUS like a photograph, made up of pixels, when you zoom in the quality gets worse - Digital photograph - in gis pixel values can represent elevation above sea level or chemical concentrations or rainfall types: satellite imagery, binary scanned file, graphic file, digital elevation models, digital orthophotos - just a grid
color theory basics
RGB: red, green, blue Additive Color Theory CMYK: cyan, magenta, yellow, black Subtractive Color Theory HSV: hue, saturation, value Gray: gray shaded rgb and cmyk r similar Bc they work similarly and use 3 or 4 original colors to create every other color, used for terrain data Cmyk is trying to use 4 original colors to subtract colors from each other to create new colors
Path
Routes along which people move throughout the city. Roads, highways, bike paths, etc.
Ground Antennas
Sends command data to satellites including orbit and clock corrections
Geodeist
Someone who measures and monitors the earth to determine the exact coordinates of any point. They are scientists who use satellite images and on-the-ground surveys to put together a complete picture of the world's measurements.
Rotation
Spin it baby! Transformation
Node
Strategic focus points for orientation. Not as significant as landmarks, but often used as junctions or points of passage. Square, roundabout, etc.
How were thiessen polygons created and what do they represent
The Thiessen method is based on the assumption that measured amounts at any station can be applied halfway to the next station in any direction, which means that for any point rainfall is equal to the observed rainfall at the closest gauge. His best known work (1911) dealt with the description of weather prediction with a geometric method for dividing land areas, that although known from Dirichlet Tessellation (1850) and the Voronoi Diagram (1908), apparently had never been used in meteorology for interpolation of measurements. The synonyms Thiessen polygons or Thiessen method have become established for this application.
relationship of the earth's surface
The geoid represents a surface of constant gravity the geoid is idealized by the notion of mean sea level which is a theoretical level of the average height of the ocean's surface - mean sea level is between mean and low tides - the reference ellipsoid is smoother than the geoid which is smoother than the physical earth's surface
Graticule
The grid created by latitude and longitude lines on the Earth
Great circle
The largest possible circle that can be created in the intersection of a plane with a sphere. Must pass through the center point of the circle
Geocoding
The process of finding the location of a street address on a map. In GIS, geocoding requires a reference dataset that contains address attributes for the geographic features in the area of interest
point feature or one-to-one dot maps
The purpose of one-to-one dot maps is to show the frequency at which the selected geographical phenomena occur, by displaying each individual occurrence as one dot.
Partitioning Data
The purpose of taking care in selecting a ranging method is twofold:• To facilitate the reading and understanding of the map. To reveal information that is not otherwise self-evident. Insure that we don't "lie" with maps
How does GPS work?
The satellites send 2 numbers, current location and current timestamp, to the receiver, which then calculates the distance from the satellite based on the speed of the signal (297,600 km/hr). when 3 of these are received from different satellites, then the receiver can create an accurate (x,y) location. for height, a 4th satellite is needed.
tangent and secant
The secant line is the red line to the right that passes through two points on the curve. The tangent line is the green line that just grazes the curve at a point. secant goes through set of points
standard deviation
The standard deviation classification method shows you how much a feature's attribute value varies from the mean. The mean and standard deviation are calculated automatically. Class breaks are created with equal value ranges that are a proportion of the standard deviation—usually at intervals of one, one-half, one- third, or one-fourth—using mean values and the standard deviations from the mean.
The Cartesian Coordinate System
The x,y graphing system, you know the one, the one with the quadrants. You can tell which quadrant you're in based on the signs of the coordinates.
hierarchy thoughts
Think about your map purpose ...and then link the arrangement and prominence of your elements to your purpose Understand the beauty of subtlety Gray can be good Think of empty space as a tool & then align your elements properly
HW#3 Measuring Circumference/Graticules
This assignment was inspired by how people originally measured the earth. Instead of using technology for every part of our calculations, we were instructed to go outside and pinpoint our actual locations. We then were instructed to use calculations that originated 2,000 years ago by Eratosthenes, a geographer who was the first person to calculate the Earth's circumference. The overall purpose of this project was to collect data from 4 different points located North, East, South, and West to calculate the Earth's circumference. Methods As the assignment stated, the diagonal paths in the Mccarthy quad are almost exactly on a North-South axis. I downloaded the Coordinates app and took screenshots of my latitude, longitude, UTM northing, and UTM easting from the north point at the end of one diagonal cross and the south point of the same diagonal cross. To get my east and west points, I gathered the same data (latitude, longitude, UTM northing, and UTM easting) at the beginning of a horizontal path across the quad and at the end of it. With this data, I calculated the distance between the north and south and east and west points. I used the north and south Distance to calculate the Polar circumference while the west and east distance were used to calculate the equatorial circumference. I eventually used these calculations to find the volume and mass of the earth.
HW #2 Routes/Coordinates/Precision/Accuracy
This homework focused on antipodal points and latitude and longitude. Antipodal points are two points that are opposite each other on the Earth. Latitude lines are the surface lines across the earth horizontally and longitude lines are vertical surface lines across the Earth. Latitude and longitude lines are important in mapping because they help to show curves in distances. I had previously never thought about how my phone's accuracy could change depending on where I am. I also never thought about how important the very specific decimals are in points on a map as they are needed to get to very specific places like stores or to track a lyft ride for example. As a design major, I could use this knowledge if I were to ever develop an app that had anything to do with tracking or specific locations.
HW assignment #2 routes, precision accuracy
This homework focused on antipodal points and latitude and longitude. Antipodalpoints are two points that are opposite each other on the Earth. Latitude lines are thesurface lines across the earth horizontally and longitude lines are vertical surface linesacross the Earth. Latitude and longitude lines are important in mapping because theyhelp to show curves in distances. first I used google maps to find the antipodal point and latitude and longitude of of Tommy trojan next I walked around my building with my smartphone using "Maps" and tested my accuracy in different places and found that it got worse when I went to the basement or below ground parking next I found distances on the map on arcgis using the measure tool.
Thiessen Polygons
This method assumes the values of un-sampled area are equal to the value of the closest sampled point
Pointillism
Thisartistictechniquereliesontheabilityoftheeyeand mind of the viewer to blend the color dots into a fuller range of tones. ThepracticeofPointillismisinsharpcontrasttothe traditional methods of blending pigments on a palette. Pointillismisanalogoustothefour-color -CMYK printing process used by some color printers and large presses that place dots of cyan, magenta, yellow and key (aka - black).
emesent
Through our solutions we automate the collection and analysis of data in challenging GPS-denied environments, delivering revolutionary efficiency, safety and operational insights to underground mining and other industries. Our core areas of expertise are drone autonomy, SLAM-based LiDAR mapping and data analytics.
Resizing
Transformation! bigger or smaller.
Visual Hierarchy
Using design techniques to carry the viewer's eye from one component to the next; helps the audience process information in design and what is most important
3 forms of map scale
Verbal scale: 1 Inch to 108 Miles Representative fraction: 1:6,842,880 Graphic or bar scale
Longitude
Vertical meridians that divide the Earth from 180 degrees E to 180 degrees W, 0 being at the Greenwich Mean
Some reasons why SDQ is a growing issue
WHo requests, collects, stores, transmits, assesses and makes decisions from the data? -Wider availability of spatial data - more users of spatial data are less aware of quality issue - more applications using spatial data mean wider uses of spatial data in possibly inappropriate situations. - data is more robust (x,y,z, and t) - "Fake" data- GIS offer limited QA/QC tools but is improving
Public Land Survey System
Way of subdividing land in the US, created by Thomas Jefferson and managed by the Bureau of Land Management. Big little grid over US
24 satellites
What is the minimum amount of satellites for the GPS?
Elements thoughts
When you make a map, know which elements to include Which are necessaryWhich are not needed (e.g., N arrow) Don't damage a good map by making "element-ary" mistakes E.g. bad title, bad legend...Know how elements get along with one another
cylindrical projection
a map created by projecting Earth's image onto a cylinder
Azimuthal Projection
a map projection in which a region of the earth is projected onto a plane tangential to the surface, typically at a pole or the equator. - if you lay a piece of paper flat on earth, top of the world or bottom, can use for airplanes and ships - does not wrap
Conical Projection Map
a map projection in which an area of the earth is projected onto a cone whose vertex is usually above one of the poles, then unrolled onto a flat surface.
bathymetric map
a map that shows the depths of a body of water such as a lake or an ocean
Relative Location
a position communicated in terms of other landmarks (down the street from the church, etc.)
How many satellites make up the Global Positioning System (GPS)?
a position x, y requires 3 satellites and height needs 4 satellites
Universal Transverse Mercator (UTM)
a two-dimensional cartesian coordinate system that records locations on the surface of the Earth. It divides the Earth into 60 zones, with each covering a six-degree band of longitude. It uses a secant transverse mercator projection in each zone. ex: Zone 52, 300669 M E, 9272983 m N
Small circle
any intersection of a plane with a sphere that does not pass through the center point.
District
areas characterized by common characteristics like architectural style, usage, commercial vs. residential vs. industrial, etc.
orbit the Earth
around the sun at a tilt of 23 1/2 degrees on axis
Controlled Image Base (CIB)
black and white imagery for visualization
5 elements of basic design in mental maps
by Kevin Lynch in Image of the City 1. Path 2. Node 3. Edge 4. Landmark 5. District
receiver
calculates 3d location and time
what blocks gps signal
canopy
secant
cuts through earth
map projection surfaces
cylindrical, conical, planar (azimuthal) azimuthal is how u find flight distances
the importance of spatial data quality
data correctness= good-to-go or garbage in = garbage out "GIGO" -correctness means many things for ex: there is a large number of parameters that go into an assessment of SDQ - assessment of correctness can be different for different data users
methods of geographic measurement
equal area, equidistance, azimuthal, conformal
Landmark
external points of orientation, usually an easily identifiable physical object in the urban atmosphere. A tower, church, etc.
relative location
familiar with landmarks but ambiguous
How to convert between DMS and Dec Degrees
from dec --> DMS: take whole number that's degrees, mult by 60, take whole number that's minutes, mult by 60, take whole number that's seconds from DMS --> dec: degrees=degrees, divide minutes by 60, divide seconds by 3600, add all together
types of azimuthal projections
gnomonic stereographic and orthographic
define the relationship between points on the graticule and points on a flat map define the relationship mathematically
graticule has longitude and latitude lines. When a point is on a flat map, you can't tell the coordinates you cant tell specific location on a regular map. With projections, graticules can be created to create grids such as UTM which can be used to pinpoint specific locations.
multi-spectral imagery
imagery from various energy wavelengths
Translation
only figure moves nothing else changes
What element did Lynch say was the most important
path bc they organize urban mobility.
Absolute location
position communicated in terms of coordinates or some other system (street address, for example)
Master Control Station
processes the data & updates satellites' navigation messages
one world terrain
researchers find info based on resources and process the source data into a simulation like structures and road surfaces, next it is stored and distributed, then an app is used to create the terrain - one world terrain will enable soldiers to experience a real experience virtually
scanned maps
scanning: transferring an analog product into a digital raster based on color
what type of functions do we use to map the world
secant functions
What fields use maps
sociology, psychology, anthropology, political science, international relations, economics
difference between state plane and utm
state plane covers the entire world utm was used for the war for communication purposes
Types of errors (General- not specific to SDQ)
systemic errors: errors that occur under similar conditions, that are consistent and therefore may be planned around or otherwise corrected random errors: errors that follow no trend and are therefore unpredictable. one way to improve quality is to take multiple readings and use the average reading
Datums and Projections
the datum is the process of measuring the earth (coordinates) when we calculate the earth using a datum, the coordinates of the earth are calculated ] graticule is created from datum - the datum is a frame of reference for measuring locations on the earth which gives us a coordinate system - use equations to calculate coordinates
balance
the organization of map elements with respect to empty space
alignment
the organization of the map elements relative to other map elements
antipodal points
the two points of intersection of a sphere with a line through its center formula= Take longitude(2nd number) and subtract it from 180 If its north you change it to south if its positive you change it to negative
tangent
touches the earth
Uses of mental maps
used to gather data about the 'imageability' (also 'legibility,' 'visibility') of a city. Let's urban/city planners include the subjective perceptions of the inhabitants for more intuitive design.
What is being shown?
which areas will be most impacted by earthquakes
Dot Density Map
• A dot density map is a type of thematic map.4,562 miles • A dot density map uses a dot symbol to show the presence of a feature or a phenomenon. A dot map relies on a visual scatter to show spatial pattern. Each dot on a dot map represents a single feature or a quantity number value.
Partitioning data methods
• Natural Breaks • Quantile -Standard Deviation -Equal Interval
methods of spatial data acquisition
• Paper maps - scanned/digitized & geo-rectified• Data tables - historic records, labor statistics, text in documents• Imagery - aerial systems and satellite sensors• Sensor webs - such as weather stations or stream gages• Surveying & Global Position Systems - geolocation data• Crowd Sourcing - Twitter & Volunteer Geographic Information
measuring positions
• The Earth is a sphere.• The rays of the the Sun are parallel to eachother. • Trigonometry permits angle measurement.
scale formula
𝑅𝑒𝑝𝑟𝑒𝑠𝑒𝑛𝑡𝑎𝑡𝑖𝑣𝑒 𝑓𝑟𝑎𝑐𝑡𝑖𝑜𝑛 =(𝑀𝑒𝑎𝑠𝑢𝑟𝑒𝑑 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒)/(𝐺𝑟𝑜𝑢𝑛𝑑 𝑑𝑖𝑠𝑡𝑎𝑛𝑐𝑒)