Albers Equal Area Projection
Files for permeability rate
Files for permeability rate
Data set reference code -- 2000-0004
To accommodate users with a variety of GIS software, the data giving the
permeability rate 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.
The orginal STATSGO mapunits for the 48 states have been merged into a
single Arc/Info polygon (vector) coverage. The permeability rate for each
standard layer of each mapunit is given by the INFO table MU_PERM, 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_perm.e00.gz (316 kbyte, uncompresses to 1.8 Mbyte)
- INFO table giving mean permeability rate for each standard layer of each
mapunit, in Arc/Info EXPORT format.
-
-
stdlayer.e00
- INFO table defining the 11 standard soil layers for which the
mean permeability rate was computed.
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
permeability rate for each of the 11 standard soil layers.
Warning -- The uncompressed version of the grid
file below is very much larger than the compressed version.
-
permgrid.e00.gz (6.6 Mbyte, uncompresses to 192 Mbyte)
- 1-km grid giving permeability rate, in Arc/Info grid format.
-
stdlayer.e00
- INFO table defining the 11 standard soil layers for which the mean
permeability rate was computed.
The 1-km gridded data are also available as a three-dimensional array of
16-bit unsigned binary integers, where each integer value represents the
permeability rate in cm/hr, multiplied by 100 -- the values were
multiplied by 100 in order to avoid decimal fractions. The data are
organized as eleven two-dimensional layers, giving, respectively, mean
permeability rate for each of the 11 standard soil layers. 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 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.
-
perm.bsq.gz (21 Mbyte, uncompresses to 294 Mbyte)
- Three-dimensional array of 16-bit unsigned integer values for
mean permeability rate for each standard layer of each grid cell.
-
stdlayer.ascii
- Table defining the 11 standard soil layers for which the mean
permeability rate was computed.
The same array is also available in LAS format (files perm.img.gz and
perm.ddr).
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/2000-0004/) are
- permgrid
- Arc/Info grid giving mean permeability rate for each standard soil
layer for each 1-km grid cell.
- ../mapunits/mu_poly
- Arc/Info coverage containing polygon version of mapunit
boundaries.
- info!MU_PERM
- INFO table giving permeability rate for each mapunit.
- info!STDLAYER
- Table defining the 11 standard soil layers for which the mean
permeability rate was computed.
Last change: 2006 Apr 14,
R. A. White / raw@essc.psu.edu