WMS:GSSHA Join SSURGO Data: Difference between revisions

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The *.dbf file associated with SSURGO shapefiles contains the following attributes: AREASYMBOL, SPATIALVER, MUSYM, and MUKEY.  Use the''' Join NRCS Data''' command to join more attributes which can then be mapped to the soil coverage.  
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SSURGO (Soil Survey Geographic database) are digital soils data produced and distributed by the Natural Resources Conservation Service (NRCS) of the National Cartography and Geospatial Center (NCGC). The database contains digital soil type and distribution information for 95% of the counties in the United States. Information covered includes soil characteristics, soil properties, and addresses limits, risks, and suitability for various uses.
The '''Join NRCS Data''' command opens three *.txt files located in the tabular folder the downloaded SSURGO data: comp.txt, chtextur.txt, and chorizon.txt.


The following data is extracted from the *.txt files:
==SSURGO Files==
* '''comp.txt''': HYDGRP
SSURGO files can be downloaded using the USDA Web Soil Survey site.<ref>{{cite web|url=https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx |title= Web Soil Survey |accessdate=May 1, 2019 |publisher=USDA Natural Resource Conservation Service}}</ref>
* '''chtextur.txt''': TEXTURE
* '''chorizon.txt''': KSAT, MOISTURE, FIELDCAP, and WILTINGPT.


==Clean and Fill Values==
The DBF files associated with SSURGO shapefiles contain the following attributes: AREASYMBOL, SPATIALVER, MUSYM, and MUKEY. Use the [[#Join NRCS Data Dialog|'''Join NRCS Data''']] command to join more attributes which can then be mapped to the soil coverage. The DBF file is not changed by this process. This allows the DBF and associated shapefiles to be joined to multiple projects.
The '''Join NRCS Data''' command opens three TXT files located in the SSURGO ''tabular'' folder containing the downloaded SSURGO data:
*"comp.txt" &ndash; Contains HYDGRP data.
*"chtextur.txt" &ndash; Contains TEXTURE data.
*"chorizon.txt" &ndash; Contains KSAT, MOISTURE, FIELDCAP, and WILTINGPT data.


Some SSURGO data may contain hybrid HYDGRP classes, such as "A/B."  Because WMS does not support hybrid HYDGRP fields, the entry will be changed to first group listed. For example, if the entry is "B/D," WMS will change the entry to "B."
==Join NRCS Data Dialog==
[[File:JoinNRCSdata.jpg|thumb|right|300 px|''Join NRCS Data'' dialog.]]
The ''Join NRCS Data'' dialog is accessed by right-clicking on a shapefile in the Project Explorer and selecting '''Join NRCS Data...'''. The dialog has the following options and sections:
*''Join Soil Texture'' &ndash; On by default, this option joins the soil texture data.
*''Join HYDGRP'' &ndash; On by default, this options joins the [[#HYDGRP Data|HYDGRP data]].
*''Fill blank values'' &ndash; Turn on this option to enable editing of the spreadsheet.
*''Compute hydraulic conductivity using equivalent conductance equation''


Often there are missing fields in the data. WMS provides the option to set a default value to be assigned to missing fields to avoid blanks.  Set these values in the dialog shown below.  
When ''Fill blank values'' is turned on, the spreadsheet will have two rows visible:
*''Soil Group'' &ndash; A drop-down listing all available soil groups in the SSURGO data.
*''Soil texture'' &ndash; A drop-down list of [[WMS:List of SSURGO soil textures|all available SSURGO soil textures]] in the SSURGO data.


[[File:JoinNRCSdata.jpg|thumb|none|left|300 px|''Join NRCS Data'' dialog]]
Because there are often missing fields in the data, this allows WMS to provide a default value to be assigned to missing fields to avoid blanks. The defaults for each of the drop-downs are the most often occurring in the SSURGO data.  


The combo boxes list the soil groups and textures that exist in the SSURGO data and are defaulted to the group and texture that occur most often.
After cleaning and filling the data, the attributes are then matched up with their corresponding MUKEY and joined to the GIS layer. If more than one entry exists for an MUKEY, the corresponding parameters that occur most frequently are joined to the layer.


After cleaning and filling the data, the attributes are then matched up with their corresponding MUKEY and joined to the GIS layerIf more than one entry exists for an MUKEY, the corresponding parameters that occur most frequently are joined to the layer.
===HYDGRP Data===
Some SSURGO data may contain hybrid HYDGRP classes, such as "A/B."  Because WMS does not support hybrid HYDGRP fields, the entry will be changed to first group listedFor example, if the entry is "B/D," WMS will change the entry to "B."


It should be noted that the shapefile's DBF file is not changed in this process. If the shapefile is opened in another WMS project, select the '''Join NRCS Data''' command again in order to join the data.
==Using Soil Type Data with GSSHA==
GSDA soil type data can be used with GSSHA. See the GSSHA Wiki for more information.<ref>{{cite web|url=http://gsshawiki.com/index.php?title=Mapping:Assigning_spatially_distributed_parameters |title=Mapping:Assigning spatially distributed parameters |accessdate=May 1, 2019 |publisher=GSSHA Wiki}}</ref> A SSURGO GSSHA soil data preparation spreadsheet is also available.<ref>{{cite web |url=https://wms.aquaveo.com/ssurgo.zip |title=ssurgoImport.xls |publisher=Aquaveo, LLC |accessdate=May 1, 2019}}</ref>


== Related Topics ==
==References==
* [[WMS:GSSHA|GSSHA Overview]]
{{reflist}}




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[[Category:GSSHA Dialogs|Join]]
[[Category:GSSHA Dialogs|Join]]
[[Category:External Links]]

Latest revision as of 21:11, 1 May 2019


SSURGO (Soil Survey Geographic database) are digital soils data produced and distributed by the Natural Resources Conservation Service (NRCS) of the National Cartography and Geospatial Center (NCGC). The database contains digital soil type and distribution information for 95% of the counties in the United States. Information covered includes soil characteristics, soil properties, and addresses limits, risks, and suitability for various uses.

SSURGO Files

SSURGO files can be downloaded using the USDA Web Soil Survey site.[1]

The DBF files associated with SSURGO shapefiles contain the following attributes: AREASYMBOL, SPATIALVER, MUSYM, and MUKEY. Use the Join NRCS Data command to join more attributes which can then be mapped to the soil coverage. The DBF file is not changed by this process. This allows the DBF and associated shapefiles to be joined to multiple projects.

The Join NRCS Data command opens three TXT files located in the SSURGO tabular folder containing the downloaded SSURGO data:

  • "comp.txt" – Contains HYDGRP data.
  • "chtextur.txt" – Contains TEXTURE data.
  • "chorizon.txt" – Contains KSAT, MOISTURE, FIELDCAP, and WILTINGPT data.

Join NRCS Data Dialog

Join NRCS Data dialog.

The Join NRCS Data dialog is accessed by right-clicking on a shapefile in the Project Explorer and selecting Join NRCS Data.... The dialog has the following options and sections:

  • Join Soil Texture – On by default, this option joins the soil texture data.
  • Join HYDGRP – On by default, this options joins the HYDGRP data.
  • Fill blank values – Turn on this option to enable editing of the spreadsheet.
  • Compute hydraulic conductivity using equivalent conductance equation

When Fill blank values is turned on, the spreadsheet will have two rows visible:

  • Soil Group – A drop-down listing all available soil groups in the SSURGO data.
  • Soil texture – A drop-down list of all available SSURGO soil textures in the SSURGO data.

Because there are often missing fields in the data, this allows WMS to provide a default value to be assigned to missing fields to avoid blanks. The defaults for each of the drop-downs are the most often occurring in the SSURGO data.

After cleaning and filling the data, the attributes are then matched up with their corresponding MUKEY and joined to the GIS layer. If more than one entry exists for an MUKEY, the corresponding parameters that occur most frequently are joined to the layer.

HYDGRP Data

Some SSURGO data may contain hybrid HYDGRP classes, such as "A/B." Because WMS does not support hybrid HYDGRP fields, the entry will be changed to first group listed. For example, if the entry is "B/D," WMS will change the entry to "B."

Using Soil Type Data with GSSHA

GSDA soil type data can be used with GSSHA. See the GSSHA Wiki for more information.[2] A SSURGO GSSHA soil data preparation spreadsheet is also available.[3]

References