Intro to Digital Mapping~ Lecture F, H, I, L, G.
traditional GIS data sources ~Lecture G
(Government Agencies (USGS, US Census, NASA, EPA)) Private companies (digital globe etc) in both cases -data is expensive (by price/taxes) -data collected by professionals with standards
compromised projection~Lecture I
-Preserve none of the four variables but attempt to balance them instead (jack of all trades, Master of none) -good for world-scale reference or thematic Equirectangular almost always a bad choice every square of lat/long is the same
Consequences of Gerrymandering~Lecture H
1. A majority of votes does not mean a majority of seats in a legislature/congress (problematic for democracy) 2. Politicians in Gerrymandered district tend to be more extreme and less open to compromise -They are not vulnerable to challengers from the other party in the next election -They are vulnerable to challengers from within their own party, often from the extreme left (democrats) or extreme right (republicans) -Thus they must be extreme themselves to keep their own party's base voters. They have no reason to comprise when making policy/law
Two ways to categorize map projections~Lecture I
1. By developable surface Cylindrical/cylinder conic/cone Planar/Plane 2. By what they distort (or really, what they preserved) Area-preserving Shape-Preserving Direction-Preserving Distance-Preserving
Maps and GIS Cartographic consequences~Lecture H
1. Carographic Partition: Drawing a line on a map to split land or area Treaty or Tordesillas, 1494 (this map 1622) Berlin Conference, 1884-85 Partition of Africa Stuck with the division for colonial convenience 2: Marking people as "others" British Empire 1886 Philadelphia racialized redlining map 1937 3. Helping produce modern governments and governing realms and kingdoms before states France was one of the first land management and patchwork and partitioning city planning undeveloped land and planning grids 4. Gerrymandering: using maps/GIS to manipulate or re-draw the boundaries of a political/voting/ district to favor a particular political party splitting votes in s geometrically fairways political power and convenience
Three decisions of classification ~Lecture L
1. How many classes? Nominal/Ordinal usually 2-3 or less than 8 2. What method to use for placing the values into classes? 3. What kind of symbology?
Zero elevation
1. Mean sea level 2. An ellipsoid/datum 3.&4. an arbitrary location on land 5. a geoid
Scale Generating Globe ~Lecture I
1. Set the globe to the scale of our map (ex: 1:24,000) 2. Turn on out light source
Persuading map readers~Lecture H
1. Something appears on a map (or doesn't) proclaiming the existence of something by showing it New York is a political territory Claiming something as mine by showing it that way make it common and normal joking about the existence of something serious-not serious excluding something from the map 2. Visual hierarchy prominent placement middle or left 3. Graphic Elements Labels and icons arrows not precise people concentric circles color overwhelm detail 4. Good Story Making a threat or threatened vilify others (serid-comic year map) 1877 Valorizing selves Matter of fact or boring
Propositions ~Lecture H
1. The map is not land/territory/Earth 2. Whose interests does the map serve? who paid for it? who benefits from it? 3. How is the design attempting to persuade you?
Aristotle~Lecture F
A Greek Philosopher, taught Alexander the Great, started a famous school, studied with Plato (350 BC) its an imperfect sphere
A Maps proposition is not the topic ~Lecture H
A Maps topic is the maps subject matter but a topic is not enough of a reason to invest time and work into making and publishing a map the proposition is what the map's authors want you to believe or accept
Generalization~Lecture L
A conclusion drawn from specific information that is used to make a broad statement about a topic or person the process of reducing the amount of information on a map through change to the geometric representation of the feature
Quantile~Lecture L
A data classification method that distributes a set of values into groups that contain an equal number of values aka equal frequency Quan = 4 Quin = 5 Equal number of states polygon per class ranked by value and broken into 4 or 5 class
Equal Interval~Lecture L
A data classification method that divides a set of attribute values into groups that contain an equal range of values. Equal step each class has an equivalent range
area feature~Lecture L
A geographic feature recorded on a map as a sequence of locations or lines that taken together trace out an enclosed area or ring that represents the feature. Example: a lake shoreline. area symbols that are homogeneous within regions -color hue -pattern shape -pattern orientation -color lightness -binary color ramp -size -color intensity yellow-red fade
line feature~Lecture L
A map feature that has length but not area at a given scale, such as a river on a world map or a street on a city map. Line weight, color, and other symbolizations allow you to show qualitative difference thicker line = bigger river
Conformal Projection~Lecture I
A map that maintains the correct shape of features on the Earth but distorts their relative size to one another. Shape-preserving at expense of distance, area, and sometimes direction
graduated symbol map~Lecture L
A map with symbols that change in size according to the value of the attribute they represent. -data class into symbol sized classes -use total data (this is alternative to normalizing a Choropleth map)
Mercator Map (conformal) ~Lecture I
A rectangular map used as a navigation tool in which the lines for longitude and latitude are straight and parallel. Distortions increases as you move further from the equator. - good for navigation - bad for thematic use works best for google chrome over used
Bench Mark (BM)~Lecture F
A relatively permanent object, natural or artificial, bearing a marked point whose elevation above or below the adopted datum is known or assumed. A high accuracy spot elevation used by surveyors.
Tissot's Indicatrix~Lecture I
A set of imaginary circles on the globe which when displayed on a map projection illustrate distortions in the map projection. If there were no distortion, all dots would be the exact same size and shape. Variations in the dots illustrate how that projection distorts the world
Choropleth Map~Lecture L
A thematic map that uses tones or colors to represent spatial data as average values per unit area. Each data category appears as a color or pattern filling an area
contour interval~Lecture F
A topographic map, tells the distance in elevation between adjacent contour lines. The vertical difference between contour lines (usually constant across all contour lines on a map) CI = Contour interval in meters
Region map projections ~Lecture I
Albers equal area- conic Lambert (azimuthal) equal area Gall-peters equal area cylindrical
Mollweide Projection (equal area) ~Lecture I
An equal-area map which shows the correct size of landmasses in relation to other landmasses but distorts shape
Distortion or preservation ~Lecture I
Area, direction, shape, distance usually preserve 1 maybe 2 usually including direction only on a globe are all 4 represented
Packing ~Lecture H
Concentring voters of an opposition party onto a single district to reduce their influence elsewhere
slope and contour lines ~Lecture F
Contour lines close together indicate a steep slope Contour lines far apart indicate a gradual slope or flat land
Volunteered Geographic Information (VGI)~Lecture G
Creation and dissemination of geographic data contributed voluntarily and for free by individuals -geographic data voluntarily added by users
New ways to get data ~Lecture G
Crowdsourcing/user-generated content data contributing by users text and pictures videos pictures restaurant reviews Product reviews Personal Location data
equirectangular projection~Lecture I
Cylindrical Projection Not Conformal or Equal The equal spacing of parallels means that the projection is equidistant in the N-S direction with a constant SF of 1.0 Equirectangular almost always a bad choice every square of lat/long is the same
Direction-Preserving Projection~Lecture I
Direction preserving
Distance Preserving ~Lecture I
Distance preserving from a point
manual~Lecture L
Fit the case or an outside standard
Web Map Services (WMS)~Lecture G
Google maps, apple maps, map quest, waze, open street, ESRI'S arcgis.com
Herodus~Lecture F
Greek Historian providing much information about Egyptians. Knows as the Father of History It doesn't look like one where I stand
Pythagoras~Lecture F
Greek philosopher and mathematician who proved the Pythagorean theorem Its perfect sphere because spheres are perfect
The North Star Polaris ~Lecture F
In the far north it is high overhead and at the equator it is near the horizon.
Contour Lines Types ~Lecture F
Index ~~600~~ Label Intermediate ~~~~~ Regular Line Contour Interval ~~~~~~ ~~~~~~~ space between V point upstream depressions hashers contour with hashers pointing downhill.
Interrupted Projections ~Lecture I
Interrupted projections gores fuller dymaxion berhaus goode's honolosine projection robinson winkel triple
Ellipsoidal Bulge ~Lecture F
Is important because it means that the lines of lat/long are farther apart at the poles than near the equator.
Sinusoidal Equal Area Projection~Lecture I
Map projection that represents areas in their true form on a two-dimensional map. Distances are only correct along parallels and central meridian. Shapes become more distorted away from the central meridian and close to the poles. goof for thematic use
How to Create an accurate geometrical reference framework ~Lecture F
Measure the exact shape of the earth ^ - simplify those measurements into v Ellipsoids (Mathematically smooth 3D) ^ - Locate the N & S pole, locate the equator halfway between, and then draw the whole. v Coordinate systems (lat/long) and datums ^ -Which we flatten into v Map projections ^ -On which we draw v Maps and GIS
Quantitative map~Lecture L
Numerical data that represents amount, magnitude or intensity (interval, ratio data) how large, wide, fast, high, or deep visual variables size, pattern texture, isolines- contour lines -color lightness or saturation
Classification~Lecture L
Ordering or grouping data entries into categories (classes) to be presented on a map. so that similar things are grouped together and different things are split into different categories/classes range of values and simplified into groups
Natural Breaks (Jenks) ~Lecture L
Picks breaks that best group similar values together naturally and maximizes the differences between classes. Good for mapping data values that are not evenly distributed select break points between selections of low & high ft values Groups values that are thought (by the algorithm) to be alike by nature of how they pack together
Standard points, lines (standard parallels, standard meridians) ~Lecture I
Points or lines where theoretically the plane meets the sphere, making for no distortion.
4th Amendment
Protection against Unreasonable Search and Seizure It prohibits unreasonable searches and seizures. In addition it sets requirements or issuing warrants: warrants must be issued by a judge or magistrate justified by probable cause, supported by oath or affirmation, must particularly describe the place to be searched and the persons or things to be seized
Relative Relief mapping symbols
Qualitative expressions of elevation - quicker, at-a-glance impressions of relief - better for untrained map readers
Absolute~Lecture F
Spot elevations a point with an elevation (often a summit or road intersection)
Cracking ~Lecture H
Spreading voters of an opposition party across multiple districts to deny them a large voting block in any one district.
Datums~Lecture F
Standard elevation reference points. They have been established throughout the country. (geodetic) datum: a reference surface/area composed of coordinate system and locally-measured control points (reference location) on an ellipsoid or geoid
Planar Projections ~Lecture I
Stereographic Orthographic Gnomonic
Visual Variables~Lecture L
The "building blocks" for map symbols Size, shape, color(Hue, value, saturation), pattern, orientation The property of a symbol/graphic marks that denotes a type of information - Geographic features of the same type/number should look the same (use the same visual variables)
Geoid~Lecture F
The actual shape of Earth, which is rough and oblate, or slightly squashed. Earth's diameter is longer around the equator than along the north-south meridians. An irregular3D surface at which the pull of gravity is constant (usually sea level) -an alternate to a geodetic ellipsoid -Used for mapping on a global scale and events inside the earth.
Geodesy ~Lecture F
The science of measuring the shape of the earth
symbology~Lecture L
The set of conventions, rules, or encoding systems that define how geographic features are represented with symbols on a map. A characteristic of a map feature may influence the size, color, and shape of the symbol used. The use of visual variables to represent information
Theme ~Lecture L
The spatial distribution of something extent and areal spread of stuff localization or regionalization thematic maps focus on one or a few themes
Irregular Oblate Ellipsoid~Lecture F
The technical shape of the earth due to peaks, valleys, and simplify irregularities to smooth it out.
dot density~Lecture L
Thematic map that uses dots to represent the frequency of a variable in a given area
Six core cartographic elements ~Lecture L
Title: Make it clean and snappy it should be large and located so that readers notice it right away Credits: Who made the map? when? in what organization? with whose data? Legend: What the symbols and colors mean in term that the readers understand Scale: Either a scale bar or a representation fraction
Datum Purpose ~Lecture F
To accurately determine location (lat/long) on the irregular surface of the Earth (usually local or regional)
Mean Sea Level (MSL)~Lecture F
True altitude, or the average height above standard sea level where the atmospheric pressure is measured in order to calibrate altitude. Related term: Above Ground Level (AGL) Average of all the low and high tides over a metric cycle
Determining Quantitive Slope ~Lecture F
Two formats 1. Slope as a fraction rise/run Slope = rise: vertical distance (in FT or Miles) / Run: horizontal distance (in miles or km) Slope 1100FT/2 miles 2. Slope as a percent derived from the fraction A: (Rise) X elevation - W elevation 8,000 ft - 3,000ft = 5,000 ft B: (Run) 20 miles (as per scale) Horizontal distance C: 5,000ft/20miles = 5,000ft/ 20mi x 5,280ft/mi = 5,000ft/105,600ft D: divide 5,000ft/105,600ft = 0.0473 E: Multiply 0.0473x100 = 4.73% slope
Datums types ~Lecture F
Two types 1. Horizontal datums (for horizontal data) North American Datum 1927 (NAD27) North American Datum 1983 (NAD83) 2. Vertical datums (for vertical and horizontal data) National Geodetic Vertical Datum 1929 (NGVD29) North American Vertical Datum 1988 (NAVD88) World Geodetic System 1984 (WGS1984) GPS is based.
Standard Line ~Lecture I
Where the surface touches the globe there is no spatial distortion
Standard Point ~Lecture I
Where the surface touches the globe there is no spatial distortion
Histogram~Lecture L
a diagram consisting of rectangles whose area is proportional to the frequency of a variable and whose width is equal to the class interval. How it breaks into groups
Contour Lines ~Lecture F
a line on a map joining points of equal height above or below sea level. Lines of constant elevation moving across multiple contour lines shows changes in elevation contour lines do not cross the only get very close together
normalization ~Lecture L
change the data so that areas are comparable
absolute relief mapping symbols~Lecture F
expressions of exact, numeric elevation. Better for direct measurements, scientific work
Personal Location Information~Lecture G
individualized geographic information about a person and their actions ~ your location Location of your private property your bodily location ~ Your geographic habits home location work location purchasing history speed of movement ~Where your friends and family are who you know, how often you communicate their location, purchasing history social contacts ~Groups you are a member of
Contributed Geographic Information (CGI) ~Lecture G
location data collected without the person's immediate knowledge or explicit decision to do so (usually from their mobile device)
Qualitative map~Lecture L
relating to, measuring, or measured by the quality of something rather than its quantity. Varying classes differentiated by type-not numerical (nominal, sometimes ordinal) visual variables shape or color(hue)
scale bar~Lecture L
section of a map that shows how much distance on the map represents a given distance on the land use absolute distance units not DD or DMS Directional Indicator: Usually a north arrow make it small Neatline or border: framing the map
equal area projection~Lecture I
shows the size of regions in correct relation to one another but distorts shape Size preserving
Selection~Lecture L
smaller scale means fewer features
Hack/Hacker~Lecture G
someone who breaks into computer systems or a particularly clever programmer/solution A creative, productive, endeavor, described at times as "quick 'n dirty" engineering
Location-based services (LBS)~Lecture G
use information about the location of mobile phone users to tailor content to specific locations technologies that perform a function based on being at a location