Shaded-relief and Color Shaded-relief maps of the Willamette Valley, Oregon USGS OFR 01-294

This digital data set, compiled from new 10-meter digital elevation model
(DEM) data, represents the physiography of the Willamette Valley, Oregon. This
new physiographic data is useful because the improved resolution allows for
better visualization of flood and fluvial features in the low lying areas of
the Willamette Valley. Many scientist are interested in the Willamette Valley
because it is subject to a variety of earthquake hazards, and its water and
geologic resources are under pressure from rapid urbanization (see sheets for a
brief description). Further, this Open-File report details the techniques used
to create these maps (See readme.pdf). It is the author's purpose to publish
these techniques and data so others may use this report to generate their own
gray scale and/or color shaded-relief maps. All information about the data and
methods used to create this report are in the readme.pdf file and this
document.

This digital dataset was compiled from newly released U.S. Geological Survey
10-meter digital elevation model (DEM) data, along with stream and
transportation coverages previously published on the internet. This report
consists of a digital representation of the physiography of the Willamette
Valley. Contained in this dataset is: 1) 10-meter DEM data for the entire
Willamette Valley; 2) the ARC/INFO grids used to create the color shaded-relief
and gray scale shaded-relief images; 3) the necessary data ARC/INFO data to
used to plot these data; and 4) several reports detailing the data formats
(this docuement) and producers used to create these datasets. The scale of the
original 10-meter DEM data should not be violated. Any use of these original
data smaller than the intended scale (1:24,000) will not yield improved
accuracy.

The databases in this report were compiled in ARC/INFO, a commercial Geographic
Information System (Environmental Systems Research Institute, Redlands,
California, with version 3.0 of the menu interface ALACARTE (Fitzgibbon and
Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon, 1991). The files
are in either GRID (ARC/INFO raster data) format or COVERAGE (ARC/ INFO vector
data) format. Coverages are stored in uncompressed ARC export format (ARC/INFO
version 8.0.2). ARC/INFO export files (files with the .e00 extension) can be
converted into ARC/ INFO coverages in ARC/INFO (see below) and can be read by
some other Geographic Information Systems, such as MapInfo via ArcLink and
ESRI's ArcView (version 1.0 for Windows 3.1 to 3.11 is available for free from
ESRI's web site: http://www.esri.com). The digital compilation was done in
version 8.0.2 of ARC/INFO with version 3.0 of the menu interface ALACARTE
(Fitzgibbon and Wentworth, 1991, Fitzgibbon, 1991, Wentworth and Fitzgibbon,
1991). Custom AMLs were written to compile the 10-meter DEM data from
7.5-minute quadrangles into large composite datasets. The data was compiled as
ARC/INFO grids and then converted to decimeter integer grids. This procedure
greatly reduces the file sizes without downgrading the data quality. Stream
coverages were merged with the grids used to create the color shaded-relief
grid composite. Further details on the techniques used to generate these maps
are available in the readme file of this report.