Joining/Relating SSURGO Data Issue

[JosiahNewman]

I am trying to relate or join a table containing soil horizon data to a soils layer in ArcMap.  The problem is that the chorizon table contains a component key such as '538359:777556' and the soil polygon layer would only have the map unit key listed as '538359.'  I have tried to go into the editing toolbar for the chorizon table, hoping to find a way to add a column and truncate the data, but it will not let me edit the chorizon table.  Any feedback or suggestion would be appreciated!  Thanks!

[RichardFairhurst]

Have you added the column while you are not in an editing session first?  Adding columns cannot be done while editing.  Also, if you are using SDE data, you have to have priveleges granted by the SDE administrator to alter the schema of an SDE table.

If you have added the column and not cannot modify the data in the table, let us know.  What database are you using for the table, since editing may differ for some databases?  Also, what version of ArcGIS are you using?

[JohnSobetzer]

Just a suggestion, but working with SSURGO data and its tables is usually much easier and less misleading if you use the free Soil Data Viewer extension for ArcGIS.  There are many one to many relationships, and many complex linking relationships in the SSURGO data, such that simple joins beyond soil names can be difficult or produce less than accurate results.

[JosiahNewman]

I'm using ArcMap 9.3, the soil database that I am using is 'soilb_US_20021.mdb,' it appears to be a read only format and will not allow me to add fields (add a column) before I go into edit mode.  I'm working on getting the extension installed but I do not have administrative rights on the computers available to me (so I'm trying to find a 'work around' solution for now).

[JohnSobetzer]

You might also check out http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm and from there perhaps go to the Web Soil Survey map service directly or use it as a WMS Server.

You might also contact your local Natural Resource Conservation Service (Soil Conservation Service) office for assistance.  I've always found their people to be extremely helpful.  In some cases they've done extra work (e.g. Vermont's Top 20) that you might find useful.