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Updated Procedure for Modifying ArcView Dbf File for Use by Soil Data Viewer 3.0

Soil Data Viewer 3.0 is designed to work with new SSURGO version 2. New SSURGO datasets certified in the version 2 format already have the MUKEY migrated into the spatial portion. This procedure is not neccesary when using Soil Data Viewer 3.0 with new certified SSURGO version 2 data. However, if only the attribute portion is available in SSURGO version 2 structure and the spatial shapefile is still the old SSURGO then the following procedure needs to be completed to migrate the MUKEY from the mapunit table in the Access database into the shapefile dbf.

In order to produce the spatial coverage used in the Soil Data Viewer, an Arc Info coverage has to be converted into a shape file. Download the cov.zip from the SSURGO site at Fort Worth (http://www.ftw.nrcs.usda.gov/SSURGO_ftp3.html). Unzip the file, load the xxx_a file into ArcView, and convert to shape naming your shape file (e.g. NM612). This process results in a group of files, one of which is named yourfilename.dbf. The file whose extension is .dbf is the soil attribute file for the .shp file.

This updated procedure handles soil surveys with any kind of map symbols, such as mapunit symbols that are case sensitive, example map symbols Bg and BG, as well as soil surveys that have numeric map symbols.

In order to use this shape file with Soil Data Viewer 3.0 one column needs to be added to the dbf file. The following instructions show you how to add, and then populate the column.

  1. Make a backup copy of original dbf file. This way, if you make a mistake during the update process, you don't have to reconvert the Arc Info coverage into a shape file.
     
  2. Open your soil survey Access database in MS Access.
     
  3. Import the dbf file, as a Dbase IV file, into the MS Access database that contains the corresponding tabular soil data. For this process to work correctly, the MS Access database must contain data for one and only one soil survey area, that soil survey area which corresponds to the shape file.
    • Access menu bar select - File, get external data, import.
    • Change file type to dBase IV (*dbf).
    • After successfully importing close import dialog.

    Note: the soil.dbf filename must not exceed 8 characters plus the 3 characters extension (dbf). When loading your dbf into Access, if you receive a duplicate column error, exit Access and load your dbf into Excel and make sure all columns in the dbf file are unique 8 character column names.
     

  4. Select the Tables tab in Access, highlight the newly imported dbf table and then hit the Design button.
     
  5. In design view, add the following column to the end of the dbf table. Enter the name in upper case to be consistent with the rest of the columns in the dbf table.
     
    MUKEY text (16 characters)

    After adding the new column, close the table and save changes.
     

  6. Create an update query that includes only the dbf table. Select Queries tab in Access and hit the New button.
    • Highlight Design view and hit Ok.
    • In the Show Table dialog scroll down and highlight your imported dbf table - hit Add button.
    • Close show table dialog.

    Make sure that the following field is visible in the dbf table in the query, scrolling if necessary: MUKEY. Double click on the field, to move it down into the query grid. Make sure your query is in update mode by selecting from the Access menu bar - Query, update query.

    • After adding the MUKEY column to the query grid you need to add information for the row Update To.

      For MUKEY, set Update To: getmukey([musym])

      Be sure to include all bolded characters above, including the square bracket [ ] and ( ).

    Note that you will not see a row titled “Update To:” unless you have specified that the query is an update query, as opposed to a select query. This is done by selecting Query on the main menu, and then selecting Update Query from that drop down menu.
     

  7.  Execute the update query. This is done by hitting the red exclamation point while in query design view. You may then save and name this query if you so desire.
     
  8. Export the updated dbf table as a Dbase IV file with the same name as the original dbf file.
    • Select the Table Tab.
    • Highlight your dbf table.
    • Select Access menu bar - file, save as/export, to an external file or database, use file type dBase IV (*dbf) and name the export the original dbf and overwrite the original dbf file.

    When this table is exported, a couple of index files will also be created. The index files have an extension of .mdx. These index files need to be deleted. The updated dbf file is now ready for use by Soil Data Viewer.

     Note on data location:

    • The access database for the Soil Data Viewer can be placed in any directory. Soil Data Viewer will first look in C:\Field_Office_Tech_Guide\Section_II , but you will have the opportunity to browse to the directory location of your soil database.
    • The set of ArcView files for the soil shapefile can be placed in any directory.