Volume 1/Appendix 3/Digital Geographic Data for the Sierra Nevada Region

DATABASE DESCRIPTION

Plans for Data Distribution via the Internet

SNEP Metadata Summary

Table A3.1

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Appendix 3

Digital Geographic Data for the Sierra Nevada Region

SNEP compiled a large amount of existing geographic data and information pertaining to the Sierra Nevada ecosystem. This material ranged from digital maps and images that spanned the entire region to analog maps and data tables for local areas, and also included original data, maps, and model outputs generated by SNEP scientists and consultants. A technical support staff was hired to integrate this information into a coherent, well-documented database and to assist the Science Team with data compilation, data quality assessment, analysis, and product generation. The staff was located in Sacramento, where it deployed a moderate-sized local network of workstation computers linked to the Internet. This appendix provides a tabular summary of the digital data compiled by SNEP and an overview of data cataloguing and archiving activities.

Database Description

The two general objectives of SNEPs database activities were the following:

1. Compile and provide existing data and information to support assessment and modeling activities of the SNEP Science Team and consultants.

2. Contribute to the development of a Sierra Nevada Information System accessible at local, state, and federal levels.

In meeting the first objective, the SNEP GIS staff acquired and integrated a large amount of geographic data on cultural, ecological, and physical environmental themes (table A3.1). To deal with the various restrictions on data distribution, SNEP classified every data set obtained or produced during the study into one of six access categories:

1. Unrestricted (public)

2. Unrestricted, but permission should be obtained from source agency

3. Accessible to Science Team and consultants, no special permission required

4. Accessible to Science Team and consultants only after signing of a waiver agreeing not to redistribute the data to anyone else

5. SNEP GIS staff only

6. File owner only

Only the first three categories of data are included in the SNEP archive. Products developed by SNEP are generally treated as unrestricted. Interim and draft versions were not generally distributed and are not part of the archival database.
A large fraction of the data was provided by the U.S. Forest Service from its Forestland and Resource Database (FRDB), in particular, the GIS ARC/INFO database developed at Pacific Meridian Resources in Emeryville, California. This database includes information on administrative boundaries, land planning units, biological resources, and physical conditions. The data are integrated vertically for each national forest. That is, maps of many different themes for each national forest have been co-registered in the GIS so that they can be overlaid and jointly analyzed. SNEP horizontally integrated selected themes across all of the national forests in order to conduct regionwide analyses. However, because the data for individual forests undergo frequent revision, the FRDB data were catalogued and archived by individual national forest (table A3.1).
Another important data source was the State of Californias Teale Data Center, which maintains statewide coverages of political boundaries, land ownership, roads, and urban areas. These data must be purchased from Teale Data Center and have been catalogued but not included in the SNEP database. Similarly, recent satellite imagery used by SNEP to map vegetation and for regional hydrologic modeling is copyrighted and must be obtained from private vendors.
Several important regional maps and databases that were produced by SNEP are available in the data archive. These include hydroelectric plants, roadless regions derived from the Forest Service and Teale Data Center, road coverages, SNEP study region and subregion boundaries, late successional forests, plant communities and dominant species, and significant areas. These data sets are documented extensively in SNEP reports as well as through associated data dictionaries.
Table A3.1 lists only geospatial data in the SNEP archive and does not include other kinds of digital information produced by SNEP such as reports, graphics, and modeling software. Eventually it is our intent to incorporate much of this information into the SNEP archive.