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63 Cards in this Set
- Front
- Back
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real maps |
hard copy "paper map" |
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virtual |
images that can be viewed but are not permanent - but can be converted to real maps |
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computer - display |
virtual map - power goes off - gone |
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mental map |
a map in your mind - i.e. driving home - something you automatically do |
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maps classified by: |
scale and purpose |
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scale |
ratio between distance on map and distance on ground unitless -fraction |
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large scale |
1:1 - 1:50,000 more detail less land
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medium scale |
1:51,000 - 1:250,000 |
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small scale |
1:251,000 - and greater - more land less detail |
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graphic scale/bar graph |
measure directly on map using scale use units you want |
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general purpose map |
usually reference maps - ex. text books, wall maps |
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planimetric |
most common (can be both general and planimetric) maps that do not attempt to show relief features in a measurable form |
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topographic map |
maps that show SHAPE and ELEVATION of terrain |
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aeronautical |
navigation of air - safety of navigation |
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nautical |
navigation of waterways - safety of navigation shows water depth |
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thematic maps |
normally done in GIS shows information about theme, idea or subject (population, vegetation, soil, railroads, geologic etc) |
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chloropleth |
areas or boundaries areas are shaded or patterned in proportion to the measurement of the statistical variable being displayed on the map - such as population density - legend shows area/boundaries |
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isoline |
lines of equal value map with continuous lines joining points of the same value (contour lines, temperature, equal altitude etc) |
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dot |
dots represent values (certain dot sizes) |
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flow |
shows direction and movement quantitative linear symbols origin/destination (trade, migration etc) legend design is critical |
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cartogram |
quantitative value by area distorts size and shape maintains contiguity difficult to read |
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GIS |
a computer based system that inputs, manipulates and outputs geographic data |
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other names for geographic data (geographic data = location/position) |
spatial data geospatial data |
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LIS defined |
a special type of GIS that manages and analyzes data related to land ownership and land related resources |
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land information systems |
Land ownership: plats. cadastral, tax maps natural resources: soil - minerals - agriculture - geology etc |
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non-spatial information systems |
management systems |
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spatial information systems |
non geographic (Cad/CAM) geographic - GIS |
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other GIS |
social economic census LIS - non-parcel based - natural resources and parcel based |
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problems in past |
accuracy data integrity no information about - reference systems, datum's, projections, coordinate systems |
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Map is a GIS product - many map uses: |
form of graphic communication decision making process record information analysis - future projections |
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GIS is based on: |
cartography |
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cartography |
art (individual - you - experience) science (natural laws) and technology (tools) of making, using and studying maps |
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map definition |
graphic representation of the earth; to scale that shows: location - position, attributes or features - information/symbols on map, relationships - how features relate distance/angle |
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USGS |
land - US Geologic Survey |
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NOAA |
air/water - National Oceanic and Atmospheric Administration |
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NGA |
National Geospatial Intelligence Agency - National Defense Maps |
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history of GIS |
roots in cartography it is the thematic overlay technique that is the basic principal of cartography that is embedded in GIS |
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start of GIS |
the arrival of the computer in the 1950s brought another essential component of GIS |
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history: 1959 |
Waldo Tobler published paper in Geographical Review outlining a simple model for applying the computer to cartography map in map out = MIMO three elements: map input - data manipulation - data output from here on better programs developed |
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history: 1960s |
Canada Geographic Information System GIS on a large scale Father of GIS - Roger F. Tomlinson - computer to "work" with Canada Resource Inventory CIA developed first systematic map database - known as world data bank US census bureau got involved - keep track of people and addresses Developed DIME (dual independent map encoding) system breakthrough in software "TIGER files" topographically integrated geographic encoding and referencing system |
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history: 1965
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Harvard lab for computer graphics pioneered a set of data structures called arc/node or vector data structures which included "topology" many GIS packages now based on this GIS model |
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history: 1970 |
ESRI (Dangermond) successful implementation of commercial GIS product - what we use new data sources - landsat aerial/satellite photography "new tool" ERDAS imagery software |
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history: 1982 |
IBM personal computer desktop GIS systems |
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1990 PC/GIS software/data/GIS exploded |
easy software - pull down menus uses in all disciplines - KEY - use layers of geographic data end result GIS = map - now a multi-billion dollar business |
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another definition of GIS |
a system of computer software, hardware and data, and personnel to help manipulate, analyze and present information that is tied to a spatial location spatial location - usually a geographic location information - visualization of analysis of data system - linking software, hardware, data personnel - a thinking explorer who is key to the power of GIS |
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two ways to input and visualize data in GIS |
Raster - grid (pixels, a location and value, satellite images and aerial photos are already in this format) vector - linear (points, lines and polygons - which are features, attributes - size, type, length etc) |
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how data is stored |
vector formats - discrete representations of reality raster formats - use square cells to model reality |
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GIS functions |
capture analyze store display query output |
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map objectives |
share information highlight relationships illustrate analysis results |
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design objectives |
manipulate the graphic characteristics fulfill the intended purpose |
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two parts to intro GIS |
academic part - terminology, homework, tests, etc. software part - ESRI, ArcGIS, ArcInfo |
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Geodesy |
Geo = earth Desy = to divide (division of the earth) - determine the size and shape of the earth -determine the gravity field of the earth PURPOSE - accurate mapping and positioning |
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geodetic surverying |
takes into account the curvature of the earth |
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plane surveying |
2-D surveying for small areas |
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great circle |
largest possible circle that can be drawn around a sphere - all spheres have great circles all meridians (longitude) are great circles the equator is another great circle - the only parallel (latitude) that is a great circle On test: a great circle is created when a plane passing through the COM (center of mass) of the Earth divides the Earth into two equal portions |
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Reference ellipsoid - Earth Math Model |
gives size and shape of Earth used for accurate mapping and positioning gives us horizontal location (Lat/Long) |
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Horizontal Geodetic Datum |
Earth reference system (GRS 80) composed of two parts - size and shape origin or lock down point on earth |
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geodetic datum types |
horizontal datums - horizontal positions (NAD 27 - old datum, NAD 83 - USGS, WGS 84 - GPS and military) each datum has a specific size and shape (reference ellipsoid name) and an origin or lock down point on the earth |
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regional vs global |
different lock down points, different size/shape of ellipoids |
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local ellipsoids |
such as the Clark Ellipsoid of 1866, were created to best fit the local geoid |
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meades ranch |
in Kansas, is designated as the geodetic base point for the North American Datum of 1927 - this is at or very near the geographic center of the forty-eight contiguous US States |
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which datum is a best mean fit to the earth |
the world geodetic system 1984 (WGS84/NAD83) - origin coincides with Earth's center of mass |
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vertical datums |
give us height or elevations based on a vertical reference datum MSL (mean sea level) tidal gauges (NGVD 29 - National Geodetic Vertical Datum - based on mean sea level) geoid (equal gravity value) as vertical reference (NAVD 88 - North American Vertical Datum - based on gravity) |
