Here is a little problem I’ve been having in ArcMap: When I create a geology map, I am using a geodatabase with the Geologic Atlas of Texas (GAT_250K-es.mdb) that contains digitized rock units and faults. This allows me to create great looking geology maps all over the State of Texas. A second geodatabase (GAT_Rockunit_Tables.mdb) includes additional attributes of the units and formations included in the first one, such as a description of the lithology.
What I would like to do but have been unable to figure out up to this point is to plot and label my geologic units on a map using MDB#1 but then label them in the legend using an attribute from MDB#2. It’s easy to join the two tables. But I can’t figure out, how to label the legend without also changing the labeling on the map. On the symbology table of the rock unit layer, you can enter a description for each record which then appears in the legend behind the actual label (in italics). I would be happy doing that if it weren’t such a pain to manually enter all these descriptions. Is there a shortcut to this ? I can’t seem to find it.
2 responses so far ↓
opinisaya // June 29, 2009 at 4:42 am |
how to create like that with VBA?
dhardy // October 19, 2009 at 11:45 am |
I’m guessing you may have solved this by now. However, if not, here’s some code that should work.
The function assumes you have a table of unique codes and descriptions in an Access database. Using DAO, it’s not a very ‘ArcObjects’ way to get the information but it works.
Just changed the hard coded table name and field name in the sql statement, and the field name whose value you want to return.
Sub SetRendererDescriptions()
Dim pMxDocument As IMxDocument
Set pMxDocument = ThisDocument
Dim pMap As IMap
Set pMap = pMxDocument.FocusMap
Dim pLayers As IEnumLayer
Set pLayers = pMap.Layers
Dim pFeatureLayer As IGeoFeatureLayer
Set pFeatureLayer = pMap.Layer(0) ‘1st layer in TOC
Dim i As Integer
Dim pLegendInfo As ILegendInfo
Dim pLegendGroup As ILegendGroup
Dim strValue As String
Dim strText As String
Dim pUVRend As IUniqueValueRenderer
Set pUVRend = pFeatureLayer.Renderer
For i = 0 To pUVRend.ValueCount – 1
varValue = pUVRend.Value(i)
strValue = varValue
”Pass renderer value to a function which retrieves a string to use for the description
strText = GetString(strValue)
pUVRend.Description(varValue) = strText
Next i
pMxDocument.UpdateContents
End Sub
Function GetString(strVal As String) As String
‘Requires reference to DAO
‘Probably not the best idea to open and close the database in this function as this is repeated every
‘time it’s called by the main sub!
Dim strPath As String
Dim db As DAO.Database
Dim strSQl As String
Dim rs As DAO.RecordSet
Dim strPlotLabel As String
Dim i As Integer
strDB = “this string should be the full path to the mdb file – including the file extension”
Set db = OpenDatabase(strDB, False, False)
strSQl = “SELECT * FROM tblLookup WHERE [LEX_RCS] = ‘” & strVal & ” ‘”
Set rs = db.OpenRecordset(strSQl, , dbOpenForwardOnly)
If Not rs.EOF Then
GetString = rs.Fields(“LEX_D”).Value
Else
GetString = “XXX”
End If
TidyUpAndExit:
rs.Close
Set rs = Nothing
db.Close
Set db = Nothing
End Function