1 / 20

Digital Map Sources I

Digital Map Sources I. The first rule of building a GIS. Try to use somebody else’s data before you even think of generating your own. 1. Geographic data portals. Nat. Geospatial Data Clearinghouse. Composed of many federal agency reps. Developing the National Spatial Data Infra-structure

raleigh
Download Presentation

Digital Map Sources I

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

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

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

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

  4. Nat. Geospatial Data Clearinghouse • Composed of many federal agency reps. • Developing the National Spatial Data Infra-structure • Working with Office of Homeland Security CS 128/ES 228 - Lecture 6b

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

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

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

  8. University sites Prominent GIS programs: • Cornell U. • U. Buffalo • U. Calif., SantaBarbara • U. Minnesota CS 128/ES 228 - Lecture 6b

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

  10. 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) CS 128/ES 228 - Lecture 6b

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

  12. 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 CS 128/ES 228 - Lecture 6b

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

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

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

  16. 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 CS 128/ES 228 - Lecture 6b

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

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

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

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

More Related