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CS 128/ES 228 - Lecture 9a1 Vector* Data Sources * mostly.

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Presentation on theme: "CS 128/ES 228 - Lecture 9a1 Vector* Data Sources * mostly."— Presentation transcript:

1 CS 128/ES Lecture 9a1 Vector* Data Sources * mostly

2 CS 128/ES Lecture 9a2 [Georgian’s] First Law of GIS Try to use somebody else’s data before you even think of generating your own

3 CS 128/ES Lecture 9a3 Geographic data portals “Be aware” of their existence, but don’t memorize details! Bear in mind while working on your course project

4 CS 128/ES Lecture 9a4 Nat. Geospatial Data Clearinghouse Composed of many federal agency reps. Developing the National Spatial Data Infra- structure Working with Office of Homeland Security

5 CS 128/ES Lecture 9a5 USGS: National Mapping Info. Primary responsibility for US mapping Mapping standards and metadata Topographic maps GNIS

6 CS 128/ES Lecture 9a6 US Bureau of the Census Address and population data, tied to the census tract TIGER maps

7 CS 128/ES Lecture 9a7 NYS GIS Clearinghouse Familiar site? Statewide aerial photographs DOT maps Gateway to many USGS & NYS products

8 CS 128/ES Lecture 9a8 Academic sites Prominent GIS programs: Cornell U. U. Buffalo U. Calif., Santa Barbara U. Minnesota

9 CS 128/ES Lecture 9a9 Commercial sites (i.e. $$)

10 CS 128/ES Lecture 9a10 ESRI’s site nice move, licensing GIS.com!) The GIS portal! ~ 100 GIS links GIS World

11 CS 128/ES Lecture 9a11 1. Digital Raster graphs (DRGs)  Scanned topographic maps at various scales  Resolution: 400 dpi typical  Projection and coordinate system: varies (read the metadata!)  Accuracy: roughly that of paper source maps  Layers: either 1 or 2. No full GIS capability

12 CS 128/ES Lecture 9a12 Commercial sources of DRGs Various companies (e.g., Delorme, Silva)  1:24,000 or 1:100,000  ~ $100/state  various tools, but one layer

13 CS 128/ES Lecture 9a13 3-D renderings

14 CS 128/ES Lecture 9a14 USGS DRGs  1:24,000 or 1:100,000  two layers - features - topography  feature classes can’t be separated

15 CS 128/ES Lecture 9a15 2. Digital line graphs (DLGs)  Scales 1:24,000 1:100,000 1:2 million  Full topological data structure (nodes, lines, areas + adjacency information)  Layers: 9 feature classes, street & address information, elevations  Projection: UTM (large & medium scale), Albers Conical Equal Area (small scale)

16 CS 128/ES Lecture 9a16 Olean DLG: roads (4 layers)

17 CS 128/ES Lecture 9a17 Olean DLG: add water features

18 CS 128/ES Lecture 9a18 Olean DLG: add contours

19 CS 128/ES Lecture 9a19 Olean DLG: all layers

20 CS 128/ES Lecture 9a20 How are geographical features represented? Two Mile Creek near campus

21 CS 128/ES Lecture 9a21 Larger rivers: both banks (lines) Allegheny River near campus

22 CS 128/ES Lecture 9a22 Major attribute codes

23 CS 128/ES Lecture 9a23 Minor attribute codes

24 CS 128/ES Lecture 9a24 3. TIGER maps U. S. Census Bureau’s DLG format Include county, census tract, & census block De facto standard/source for most commercial geocoding and trip planning software Topologically Integrated Geographic Encoding & Referencing system

25 CS 128/ES Lecture 9a25 The TIGER map browser

26 CS 128/ES Lecture 9a26 Center on a familiar point…

27 CS 128/ES Lecture 9a27 TIGER for Allegany NY

28 CS 128/ES Lecture 9a28 Census Bureau databases American Factfinder Reports in table or map form Joins or relates?

29 CS 128/ES Lecture 9a29 Thematic maps

30 CS 128/ES Lecture 9a30 Resolution to the census tract

31 CS 128/ES Lecture 9a31 Local demographic stats

32 CS 128/ES Lecture 9a32 Summary: digital data sources  Digital raster graphs (DRGs)  Digital line graphs (DLGs)  TIGER files


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