Data Sources, Collection, and Conversion 

Data Sources

    All digital data was collected from two main sources, which can by accessed via clicking the large buttons:

GIS @ Bureau of Land Management for Oregon and Washington State

Vegetation data - polygons of major plant groupings
Elevation Data - 50ft interval contours
Fire History Data - Fire Incidence 1980-1989

PRISM Climate Mapping

Precipitation polygon data for June, July and August; statewide for Oregon

While the Oregon Geospatial Data Clearinghouse also has allows free access to and usage of statewide digital coverages that I could have used in this project, I decided to attempt to download all necessary data from as few sources as possible because this minimized signigicant projection compatability problems, discussed further in Data Compatability and Analysis Issues . Because the Bureau of Land Management provided more of the requisite data than the state Geospatial Data Clearinghouse, I selected the BLM as my primary data source after attempting to manipulate and compile various data sets between sources.

As mentioned, all data used in this project was downloaded from online sources disseminating free data.  All data was downloaded in ArcInfo export format (.e00 files).  However, because all of my analyses were performed in raster format (Boolean analysis precludes grid data), vector data needed to be converted not only to make it manipulable in Idrisi, but also to be rasterized from the original vector format.  This was accomplished by:

Converting .e00 files into ArcView shapefiles
Using the ArcView Spatial Analyst extension to convert all data into a grid
Exporting all grid "themes" as ASCII Raster formats
Importing ASCII Raster export files into Idrisi as a software specific format

 

Agnieszka Leszczynski
2001
Geography 355
Simon Fraser University