GEO 465/565 - Lecture 6
Maps as Numbers - Part 2

NSDI Notes

TIN: Triangulated Irregular Network - GRAPHIC

Based on the Delaunay triangulation model of a set of irregularly distributed points.

Way to handle raster data with the vector data structure. Common in some GISs and most AM/FM packages

More efficient than a grid

Formats

Data formats can be industry standard, commonly accepted or standard

Vector Data Formats

Page languages are HPGL, PostScript, and Autocad DXF

True vector GIS data formats are DLG and TIGER, which have topology

The TIGER data structure - GRAPHIC

Raster Data Formats

Most GISs accept TIF, GIF, JPEG or encapsulated PostScript, which are not georeferenced

DEMs are true raster data formats

Data Exchange

If a GIS supports many data structures, changing structures becomes the users responsibility

Changing vector to raster is easy; raster to vector is hard.

Data also are often exchanged or transferred between different GIS packages and computer systems

The history of GIS data exchange is chaotic and has been wasteful

Vector to raster exchange errors - GRAPHIC

Transfer Standards

GIS Data Exchange

In the United States, the SDTS was evolved to facilitate data transfer

SDTS became a federal standard (FIPS 173) in 1992

SDTS contains a terminology, a set of references, a list of features, a transfer mechanism, and an accuracy standard

Both DLG and TIGER data are available in SDTS format

Other standards efforts are DIGEST, DX-90, the Tri-Service Spatial Data Standards, and many other international standards

Efficient data exchange is important for the future of GIS

Overview of the National Spatial Data Infrastructure (NSDI)

• Data
  • The most expensive investment for an organization
  • Created by many different organizations
  • To solve many different problems
  • Using many different methods and technologies
• Data, Metadata, Clearinghouse, Standards, and Partnerships are elements are linked in a very explicit way to assure the function of the enterprise.
• Categories of Geospatial Data
  • Community-developed data sets usually derived for a single purpose but made available for potential re-useData sets developed to a common content specification for high re-use potential. These are known as "Framework" data.
• Framework provides. . .
  • foundation to which spatial information and attributes can be added.
  • base on which other themes of data can be compiled.
  • context to orient and link the results of analyses to the landscape
• Framework Data
• Metadata developments
  • Importance of metadata
  • Refinement of the FGDC Metadata Standard
  • Harmonization with international standards
  • Collection tools available
  • Training available from FGDC
• Clearinghouse provides...
  • Discovery of spatial data
  • Distributed search worldwide
  • Uniform interface for spatial data searches
  • Advertising for your data holdings
• Who builds standards?
  • FGDC Standards working group in partnership with . . .
  • FGDC Thematic subcommittees
  • Concerned organizations
  • Producers and users of geospatial data
• Types of standards
  • Data content
    • Common classifications
    • Common collection criteria
  • Data management
    • Metadata
    • Spatial Data Transfer Standard (SDTS)
• Standards under development
  • Base Cartographic
  • Cultural and Demographic Metadata
  • Geodetic Control Networks
  • Transportation Network Profile
  • RiverReach File Version 3.0
  • Earth Cover Classification
  • Geologic
  • Facilities
• Recognized State GIS Councils
  Oregon and...
  • Texas
  • North Carolina
  • Arizona
  • Wyoming
  • Nebraska
  • New Jersey
  • Kansas
  • Kentucky
  • Louisiana
  • Minnesota
  • Utah
  • Alaska
  • California
  • Florida
  • Vermont
  • Michigan (IMAGIN)
  • New Mexico
  • Wisconsin
• Cooperative programs
  • Competitive Cooperative Agreements Program
  • Framework Demonstration Projects Program
  • NSDI Benefits Program
• The NSDI is built through the actions of thousands
  of participants

  Web site of the week... http://buccaneer.geo.orst.edu

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