STATSGO soil characteristics for the conterminous United States
Dataset Identification:
Resource Abstract:
This digital data release consists of an ARC/INFO grid and associated INFO tables. The grid is called MUID and has STATSGO
(U.S. Department of Agriculture, 1994) soil mapping unit identifiers gridded on a 1-kilometer resolution for the conterminous
United States. The INFO tables have soil characteristics data in them. The ITEMS in the tables are weighted average values
for several soil characteristics in the STATSGO data base. The weighted average values were computed by aggregating the soil
layers and components in the data base. The INFO tables are called MUID.LAYER, MUID.COMP, MUID.KFACT, MUID.TFACT, and MUID.WEG.
The INFO tables can be related or joined to the MUID grid or to individual State coverages (grids or polygons) of MUIDs. Joining
or relating the tables to the MUID grid creates 1-kilometer resolution grids of the soil characteristics for the conterminous
United States. The soil characteristics in MUID.LAYER are permeability (PERML and PERMH in the STATSGO data base), available
water capacity (AWCL and AWCH), bulk density (BDL and BDH), and organic matter (OML and OMH). The soil characteristics in
MUID.COMP are slope (SLOPEL and SLOPEH), depth to seasonally high water table (WTDEPL and WTDEPH), and depth to bedrock (ROCKDEPL
and ROCKDEPH). The soil characteristic in MUID.KFACT is the soil erodibility factor (KFACT), the soil characteristic in MUID.TFACT
is the soil loss tolerance factor (TFACT), and the soil characteristic in MUID.WEG is the wind erosion group (WEG). The MUID
grid and INFO tables were created with a set of arc macro language (aml) and Fortran programs. Send electronic mail to dwolock@usgs.gov
to obtain copies of the computer code. (See Procedures_Used.)
Citation
Title STATSGO soil characteristics for the conterminous United States
The data were derived for use in regional (multi-state) and national studies requiring estimates of soil characteristics.
The georeferenced soil characteristics were intended to be averaged over large areas, such as over a river basin, and used
(1) for watershed simulation models that require spatially lumped estimates of soil hydraulic parameters and (2) as explanatory
variables in regional and national water-quality assessment studies.
Resource language:
eng; USA
Resource progress code:
completed
Resource Maintenance Information
maintenance or update frequency:
asNeeded
Constraints on resource usage:
Constraints
Use limitation statement:
Although this data set has been used by the U.S. Geological Survey, U.S. Department of the Interior, no warranty expressed
or implied is made by the U.S. Geological Survey as to the accuracy of the data and related materials. The act of distribution
shall not constitute any such warranty, and no responsibility is assumed by the U.S. Geological Survey in the use of this
data, software, or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not
imply endorsement by the U.S. Government.
Constraints on resource usage:
Legal Constraints
use constraint:
otherRestrictions
Other constraints
Use Constraints: The STATSGO data are compiled by generalizing more detailed county soil survey maps. (See U.S. Department
of Agriculture, 1994 for an explanation of how the STATSGO data were generated.) Because of their spatially generalized nature,
the STATSGO data cannot be used to accurately estimate average soil characteristics for small areas. The STATSGO data-use
information document states that "STATSGO data are not detailed enough to make interpretations at a county level" (U.S. Department
of Agriculture, 1994).
Procedures used The STATSGO data were processed on a Data General desktop computer using Data General Unix operating system.
Processing was accomplished using a set of amls and Fortran programs. Contact dwolock@usgs.gov for copies of the computer
code. Deriving MUID "average" values for land-surface slope, depth to the seasonally high water table, and total soil thickness
required that a weighted average value be computed for all the soil components in a soil mapping unit. The average was computed
by weighting the component values by their percentage composition of the MUID. For example, suppose MUID AL005 was 35 percent
component A, 25 percent component B, and 40 percent component C. Further assume that the SLOPEL value for component A was
3 percent, the SLOPEL value for component B was 6 percent, and the SLOPEL value for component C was missing. The weighted
average value (AVE) of SLOPEL for MUID AL005 would then be: AVE = (0.35 * 3 + 0.25 * 6) / (0.35 + 0.25) = 4.25 inches per
hour. Deriving MUID average values for permeability, available water capacity, bulk density, organic matter content, soil
erodibility factor, soil loss tolerance factor, and wind erodibility group required that a weighted average value be computed
for all the soil layers in a soil component, and then a weighted average value be computed for all the soil components in
a soil mapping unit. First, the component average values were computed by weighting the layer values by their thickness. Second,
the MUID average was computed by weighting the component average values by their percentage composition of the MUID. Each
step of the two-step weighting process was done exactly as described above, except first the layer values were weighted by
their thicknesses, and then the component values were weighted by their percentage composition. The following steps describe
how the STATSGO data were processed. 1. Place the STATSGO compact disk (CD) in reader (path name should be /pdd/cdrom/). 2.
Start up ARC and then GRID in a working directory that contains the file fnsoils and the grid MASKGRD. (The file fnsoils contains
State names and abbreviations for those States to be processed. A complete list of the State names and abbreviations is given
at the end of the Procedures_Used section. The grid MASKGRD sets the processing window and cell size. A description of MASKGRD
is given at the end of the Procedures_Used section.) 3. Open a plotting window (device 9999). 4. Launch soilcd.aml. This aml
calls statsmuid.aml. This step generates a subdirectory for each State, and it derives a numeric MUID grid for each State.
5. Launch mergemuids.aml. This aml merges the MUID grids for each State into a master MUID grid (called MUID) for the conterminous
United States. A mask grid (called MASKGRD) must be in the working directory to set the window and cell size. 6. Launch copytab.aml
from the main working directory with the arguments muidgrd.tab and muid.mast. This aml copies the MUIDGRD INFO tables from
each State directory into a master table called MUID.MAST in the main working directory. 7. Use joinitem to join MUID.MAST
to MUID.VAT. 8. Drop the item GOTDAT from MUID.VAT. 9. Delete the nmexico line from fnsoils. The COMP table for New Mexico
on the CD is incorrect. (See step 13.) 10. Launch compcd.aml. This aml calls comppro.f. This step computes soil component
weighted average values for ROCKDPEL, ROCKDEPH, WTDEPL, WTDEPH, SLOPEL, SLOPEH, and COMPPER. The item COMPPER is the percentage
of components used to determine the weighted average value. Component percentages do not always sum to 100 percent. A separate
INFO table called NEWCOMP.TAB is created in each State directory. 11. Launch statscdbig.aml so that it calls statstab.aml.
This aml can call either statstab.aml or statsmult.aml. (Commenting out one of the call statements in statscdbig.aml determines
which aml will run.) When statstab.aml is run, soil characteristics averages aggregated first by layer, and then by component,
are computed for PERML, PERMH, AWCL, AWCH, OML, OMH, BDL, and BDH. The item COMPPER (percentage of total components aggregated)
is also computed. A separate INFO table called NEWLAYER.TAB is created in each State directory. The Fortran programs layertabone.f
and comptab.f are called by statstab.aml. The Fortran programs layertabone1.f and comptab1.f are called by statsmult.aml.
12. Launch statscdbig.aml so that it calls statsmult.aml. Running statsmult.aml from within statscdbig.aml will compute KFACT,
TFACT, and WEG. Separate INFO tables called KFACT.TAB, TFACT.TAB, and WEG.TAB are created in each State directory. 13. Get
correct copies of the COMP and LAYER tables for New Mexico and place them in the nm directory. The COMP table on the CD is
incorrect. A correct version of the COMP table can be obtained from Fred Minzenmayer (fminzenm@ftw.nrcs.usda.gov). 14. Launch
compnm.aml from the nm directory. This aml computes soil component weighted average values of ROCKDPEL, ROCKDEPH, WTDEPL,
WTDEPH, SLOPEL, SLOPEH, and COMPPER for the New Mexico data. 15. Launch multnm.aml from the nm directory. This aml computes
KFACT, TFACT, and WEG for New Mexico. The Fortran programs layertabone1.f and comptab1.f are called by multnm.aml. 16. Launch
statsnm.aml from the nm directory. This aml computes PERML, PERMH, AWCL, AWCH, BDL, and BDH, OML, and OMH for New Mexico data.
The Fortran programs layertabone.f and comptab.f are called by statsnm.aml. 17. Launch copytab.aml from the main working directory
with the arguments KFACT.TAB and KFACT.MAST. This aml copies the KFACT INFO tables from each State directory into a master
table in the main working directory. The table MUID.KFACT is a copy of KFACT.MAST. 18. Launch copytab.aml from the main working
directory with the arguments NEWCOMP.TAB and NEWCOMP.MAST. This aml copies the NEWCOMP INFO tables from each State directory
into a master table in the main working directory. The table MUID.COMP is a copy of NEWCOMP.MAST. 19. Launch copytab.aml from
the main working directory with the arguments NEWLAYER.TAB and NEWLAYER.MAST. This aml copies the NEWLAYER INFO tables from
each State directory into a master table in the main working directory. The table MUID.LAYER is a copy of NEWLAYER.MAST. 20.
Launch copytab.aml from the main working directory with the arguments TFACT.TAB and TFACT.MAST. This aml copies the TFACT
INFO tables from each State directory into a master table in the main working directory. The table MUID.TFACT is a copy of
TFACT.MAST. 21. Launch copytab.aml from the main working directory with the arguments WEG.TAB and WEG.MAST. This aml copies
the WEG INFO tables from each State directory into a master table in the main working directory. The table MUID.WEG is a copy
of WEG.MAST. List of State name abbreviations in the file called fnsoils- al alabama ar arkansas az arizona ca california
co colorado ct connecticut de delaware fl florida ga georgia ia iowa id idaho il illinois in indiana ks kansas ky kentucky
la louisiana ma massachusetts md maryland me maine mi michigan mn minnesota mo missouri ms mississippi mt montana nc ncarolina
nd ndakota ne nebraska nh nhamshire nj njersey nm nmexico nv nevada ny nyork oh ohio ok oklahoma or oregon pa pennsylvania
ri risland sc scarolina sd sdakota tn tennessee tx texas ut utah va virginia vt vermont wa washington wi wisconsin wv wvirginia
wy wyoming Description of the grid MASKGRD- Cell Size = 1000.000 Data Type: Integer Number of Rows = 3058 No Value Attribute
Table Number of Columns = 4771 Attribute Data (bytes) = -1 BOUNDARY STATISTICS Xmin = -2462303.668 Minimum Value = 0.000 Xmax
= 2308696.332 Maximum Value = 0.000 Ymin = 176796.666 Mean = 0.000 Ymax = 3234796.666 Standard Deviation = -2.000 COORDINATE
SYSTEM DESCRIPTION Projection ALBERS Units METERS Spheroid CLARKE1866 Parameters: 1st standard parallel 29 30 0.000 2nd standard
parallel 45 30 0.000 central meridian -96 0 0.000 latitude of projection's origin 23 0 0.000 false easting (meters) 0.00000
false northing (meters) 0.00000 Reviews applied to data The MUID grid and associated INFO tables received technical reviews
in January and February 1997. The review materials provided to each reviewer included the following: (1) the MUID grid, (2)
the associated info tables, and (3) a draft of the documentation that will accompany the grid and INFO tables. The reviewers
were asked (1) to evaluate technical correctness of the method used to derive the MUID grid and info tables, and (2) the completeness
and accuracy of the documentation. The reviewers' comments and author's responses are summarized below. REVIEWER- Kerie Hitt,
USGS 1. Rename the INFO tables so that they all begin with the suffix MUID. Response: Done. 2. Remove the boiler plate text
under sections not filled out. Response: Done. 3. Specify the platform and operating system. Response: Done. 4. Consolidate
steps 17-21 in the Procedures_Used section. Response: Consolidation of the steps would decrease the clarity of the description.
Therefore, I did not consolidate steps 17-21. 5. List the STATSGO polygon coverage as a related spatial data set. Response:
Done. 6. Clarify the elimination of MUIDs associated with water bodies. Response: Done. 7. Clarify what Fortran programs are
called by which amls. Response: Done. REVIEWER- Barbara Ruddy 1. Clarify aggregation process in LAYER and COMP tables. Response:
Done. REVIEWER- Naomi Nakagaki 1. Rename tables so that they all begin with MUID. Response: Done. 2. Include all amls and
Fortran programs in documentation. Response: At this point, I am not going to include the amls and programs. The programs
are not well documented and may evolve over time. When I am confident that the programs and their output will remain unchanged
for some time, then I will document the programs and include them with the data set documentation. Related spatial data sets-
STATSGO polygon coverages of MUIDs for each of the conterminous United States are on the 1994 CD-ROM. The INFO tables MUID.xxx
can be joined or related to the polygon coverages using the alphanumeric MUID as the relate item. Other references cited-
U.S. Department of Agriculture, 1994, State Soil Geographic (STATSGO) Data Base, Data use information. U.S. Department of
Agriculture Miscellaneous Publication Number 1492, Fort Worth, Texas. 35 p. Notes- If joinitem is used to connect the INFO
tables to MUIDs, remember to weed out the MUIDs for which there are no soil data values in the INFO tables. This can be done
by reselecting for GOTDAT EQ 1. GOTDAT is an item in the INFO table that indicates data exist for an MUID. The "official"
STATSGO data base on CD-ROM in ARC/INFO format from the U.S. Department of Agriculture was used to generate the derivative
data. The COMP table for New Mexico on the CD is corrupt/bad/wrong. The U.S. Department of Agriculture provided a correct
COMP table, which is used to generate the data described here. A correct version of the COMP table can be obtained from Fred
Minzenmayer (fminzenm@ftw.nrcs.usda.gov). There is an error in the LAYER table for Colorado. A WEG value is out of range for
component 2 of MUID CO326. This component was ignored in computing the weighted average value of WEG for CO326. The average
value of WEG was computed "by hand" for CO326 and substituted into the table WEG.MAST. There are errors in WTDEPL and WTDEPH
values for the following MUIDs: CA004, CA050, CA765, CA767, KS443, MT144, NM722, OK050, OK105, and OK142. The values for WTDEPL
and WTDEPH were out of range for components of these MUIDs. The erroneous values were excluded in computing the weighted average
values for these MUIDs. Average values of WTDEPL and WTDEPH were computed "by hand" for these MUIDs and substituted into the
table NEWCOMP.MAST. The use of trade names in this documentation is for identification purposes only and does not constitute
endorsement by the U.S. Geological Survey.
point of contact
-
pointOfContact
individual Name David Wolock
organisation Name
U.S. Geological Survey
position Name Research Hydrologist
Contact information
Telephone
Voice 1-888-275-8747
Fax 785-832-3500
Address
4821 Quail Crest Place, Lawrence, KS, 66049-3839
Country USA
notes: This metadata was automatically generated from the FGDC Content Standards for Digital Geospatial Metadata standard (version
FGDC-STD-001-1998) using the 2012-06-20T17:21:00 version of the FGDC RSE to ISO 19115-2 transform.