Data Sources, Processing and Manipulation:

The elevation data for the Lake Tahoe basin was obtained from the Lake Tahoe Data Clearinghouse as a digital elevation model of resolution 10m, derived from 4 USGS topographic quadrangle maps as well as hypsographic data using photogrammetric methods. The original DEM was converted to an Arcraster ASCII file which was employed to create the raster image used for spatial analysis.

DEM IDRISI

Road data, stream and lake data, as well as human-made object data (docks, wharfs and built up areas) were obtained from the Lake Tahoe Data Clearinghouse as published by the USGS. All were obtained in ARC INFO format requiring conversion to raster images. The lake data also required re-projection.

Land cover data was obtained from the Environmental Protection Agency, derived from a mosaic of 18 Landsat images. Land cover was divided into 8 major catagories, each of which contained various levels of subdivision. Additional vegetation cover data was obtained from the Lake Tahoe Data Clearinghouse. These data were obtained in ARC INFO format, with the vegetation data requiring re-projection.

LAND COVER & VEGETATION

Soil data in the form of a ARC INFO, Natural Resource Conservation Service soil map for the Lake Tahoe Basin was obtained from the SSURGO Database. This file required reprojection as well as conversion to a raster image.

Census data were derived from US Census Bureau TIGER files. The final data were obtained in ARC INFO format from the Lake Tahoe Data Clearinghouse and the final census tract boundaries from the US Census Bureau. This data set was originially much too large in volume requiring much data filtering to include only necessary population statistics and the census tract boundaries which they pertain to. Much of the population data required conversion to metric units in ARCMap.

DEM image with lakes, built up area and road vector layers.

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