1970s GIRAS Land Use
Digital land-use data for the late 1970s were acquired from the USGS National Mapping Division, as part of the Geographic Information Retrieval and Analysis System (GIRAS). Land-use categories were determined based on the Anderson Level II classification system (Fegeas and others, 1983*). The final map was compiled from a mosaic of National Aeronautic and Space Administration high-altitude U2/RB-57 aerial photographs at scales smaller than 1:60,000, and these were registered to 1:250,000-scale topographic base maps. GIRAS land use (27 K gif) for the Willamette Basin was clipped from the original Oregon State coverage. GIRAS land-use percentages for the basin are: forest -- 70%, agriculture -- 22%, and urban -- 5%.
*Fegeas, R.G., Claire, R.W., Guptill, S.C., Anderson, K.E., and Hallam, C.A., 1983, U.S. Geological Survey digital cartographic data standards--Land use and land cover digital data: U.S. Geological Survey Circular 895-E, 21 p.
1992-93 TM Land Cover
An updated land-cover classification, based on June and August 1992-93 thematic mapper (TM) data, has been created for the Willamette Basin by the EROS Data Center in collaboration with the Willamette NAWQA study. The TM mosaic (216 K gif) can be obtained by calling User Services at the EROS Data Center (605/594-6151) and specifying order ID number E-1987-99cT in the PAO file. The classified land-cover map (viewable image coming) is available by specifying order ID E-1988-99cT. Color prints of various sizes and 9-inch color positive transparencies are available.
Please address questions regarding the TM land-cover maps to Paul Seevers:
phone: (605) 594-6010
Paul would appreciate any feedback you may have on the land-cover maps, especially regarding their utility for data analysis or for making management decisions.
Arc/INFO GRID Export File
An ARC GRID file of the classified land-cover map is available for download. A compressed file, wil2rg.e00.gz is about 13 megabytes; and about 235 megabytes when uncompressed. The file contains the export file (wil2rg.e00). You may also want the readme file, willamette.readme, which provides information on how the maps were produced and details regarding the land-cover classification.
If you have any problems or questions, Call Mark Uhrich, (503) 251-3292.
Photographs from our retrospective fact sheet on nitrogen
Grass seed and grains are the primary crops in the southern Willamette Basin (167K gif). In the northern basin (146K gif), crops are much more diverse and include flowers (for seed and bulbs), vegetables, berries, orchards, hops, and vineyards. Irrigation (145K gif) is important in the northern basin and along major rivers in the southern basin.