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Albers Equal Area Projection

Files for surface soil erodibility factors

Files for surface soil erodibility factors

Data set reference code -- 1998-0111

To accommodate users with a variety of GIS software, the data giving the surface soil erodibility factors are available in several different formats. The files needed by each of the types of user below are described separately.

NOTE -- Most of these files have been compressed using the GNU gzip program, as indicated by the .gz file extension. Users who do not have access to the gunzip decompression program can request that files be uncompressed prior to transfer via ftp. In some cases, however, the uncompressed file may be very much larger than the compressed version, greatly increasing file transfer time.

Arc/Info polygon file users

The orginal STATSGO mapunits for the 48 states have been merged into a single Arc/Info polygon (vector) coverage. The surface soil erodibility factors for each standard layer of each mapunit is given by the INFO table MU_KFACT, which may be RELATEd to the mapunit coverage using "MUID" as the relate item. The needed files are

mu_poly.e00.gz (104 Mbyte, uncompresses to 249 Mbyte)
Mapunit polygon coverage in Arc/Info EXPORT format.
mu_kfact.e00.gz (79 kbyte, uncompresses to 431 kbyte)
INFO table giving mean surface soil erodibility factors, adjusted (KFACT) and not adjusted (KFFACT) for rock fragments, in Arc/Info EXPORT format.

Arc/Info grid file users

The mapunits have been gridded at 1-km cell size. The value attribute table (VAT) for the Arc/Info grid listed below contains the mapunit indentifier, MUID, the mapunit serial number, MUSERIAL, and the mean surface soil erodibility factors KFACT and KFFACT.

Warning -- The uncompressed version of the grid file below is very much larger than the compressed version.

kfactgrid.e00.gz (6.3 Mbyte, uncompresses to 191 Mbyte)
1-km grid giving surface soil erodibility factors, in Arc/Info grid format.

Other users of gridded data

The 1-km gridded data are also available as a three-dimensional array of 8-bit unsigned binary integers, representing the values of KFACT and KFFACT multiplied by 100. The data are organized as two two-dimensional layers, giving, respectively, mean surface soil erodibility factors adjusted (KFACT) and not adjusted (KFFACT) for rock fragments. Within each layer, the values are arranged by horizontal rows. All values for the first layer are given first, starting with the value for the left (western) end of the top (northern-most) row, and continuing left to right along the row. The data for the last row of the first layer are then followed by the top row of the second layer, and so on.

Each layer of the array contains 2896 rows of 4616 values each. Code for reading the binary array is available in Fortran 77 and C.

Warning -- The uncompressed version of the BSQ file below is very much larger than the compressed version.

kfact.bsq.gz (3.1 Mbyte, uncompresses to 27 Mbyte)
Three-dimensional array of 8-bit unsigned integer values for mean surface soil erodibility factors multiplied by 100.
mu_kfact.ascii.gz (76 kbyte, uncompresses to 315 kbyte)
Table giving, for each STATSGO mapunit, the mapunit ID, mapunit serial number, and values of KFACT and KFFACT.
The same array is also available in LAS format (files kfact.img.gz and kfact.ddr).

Local users on the ESSC network

The file systems containing the datasets are cross-mounted on the local ESSC computer network. Local Arc/Info users may find it more convenient to copy necessary files directly to their own workspaces using the Arc/Info COPY and COPYINFO commands. The needed directories and files (under directory $DSREF/1998-0111/) are
kfactgrid
Arc/Info grid giving mean surface soil erodibility factors KFACT and KFFACT for each 1-km grid cell.
../mapunits/mu_poly
Arc/Info coverage containing polygon version of mapunit boundaries.
info!MU_KFACT
INFO table giving surface soil erodibility factors values for each mapunit.
Last change: 2006 Apr 14, R. A. White / raw@essc.psu.edu

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3/8/2006