1. CS 128/ES 228 - Lecture 6b1 Digital Map Sources I

2. CS 128/ES 228 - Lecture 6b2 The first rule of building a GIS Try to use somebody else’s data before you even think of generating your own

3. CS 128/ES 228 - Lecture 6b3 1. Geographic data portals

4. CS 128/ES 228 - Lecture 6b4 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 228 - Lecture 6b5 USGS: National Mapping Info. Primary responsibility for US mapping Mapping standards and metadata Topographic maps GNIS

6. CS 128/ES 228 - Lecture 6b6 US Bureau of the Census Address and population data, tied to the census tract TIGER maps

7. CS 128/ES 228 - Lecture 6b7 NYS GIS Clearinghouse Familiar site? Statewide aerial photographs DOT maps Gateway to many USGS & NYS products

8. CS 128/ES 228 - Lecture 6b8 University sites Prominent GIS programs: Cornell U. U. Buffalo U. Calif., Santa Barbara U. Minnesota

9. CS 128/ES 228 - Lecture 6b9 Commercial sites ESRI’s site (nice move, licensing GIS.com!) The GIS portal! ~ 100 GIS links GIS World

10. CS 128/ES 228 - Lecture 6b10 2. Geographic exchange formats De facto standard: a.k.a. “industry standard” based on market success of a particular software standard (ex. ArcView shapefile) De jure standard: developed by professional organization, such as ANSI or ISO (ex. SDTS in US) Regulatory standard: enforced by government (ex. cadastre maps for property/tax purposes)

11. CS 128/ES 228 - Lecture 6b11 Value of digital exchange standards

12. CS 128/ES 228 - Lecture 6b12 Examples of national standards SDTS (US): Spatial Data Transfer Standard (now mandatory for all federal agencies) CGIS (Canada): Canadian Geomatics Interchange Standard NTS (UK): National Transfer Standard

13. CS 128/ES 228 - Lecture 6b13 3. Raster data formats

14. CS 128/ES 228 - Lecture 6b14 Remote sensing data sets  NASA’s EOS program  France’s SPOT http://earthobservatory.nasa.gov

15. CS 128/ES 228 - Lecture 6b15 EOS 19 Feb news item: Lack of Snow Drives Iditarod North

16. CS 128/ES 228 - Lecture 6b16 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

17. CS 128/ES 228 - Lecture 6b17 Sources of DRGs Commercial sources (e.g., Delorme, Silva)  1:24,000 or 1:100,000  ~ $100/state  various tools, but one layer

18. CS 128/ES 228 - Lecture 6b18 3-D renderings

19. CS 128/ES 228 - Lecture 6b19 USGS DRGs  1:24,000 or 1:100,000  two layers - features - topography  feature classes can’t be separated

20. CS 128/ES 228 - Lecture 6b20 DRG – viewing both layers The contour layer covers the features layer! What to do???