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I'm using ArcGIS 10. In ArcMap's table of contents (TOC), is there a way to have the "Layer Name" automatically show a count of the total number of features in each layer?

I was thinking the TOC would look something like this:

  • Roads (27)
  • Streams (100)
  • Parcels (12)

I found this option for Unique Value renders, but:

  1. I am not an ArcObjects guy, and
  2. I want to work with just the Single Value renderer.

The "List By Selection" tab sort of has this capability, but only when there are selected features.

  • Are you looking to do this for a single layer in your map (that you have the name of), or having it applied to all layers on your map by default? – CHenderson Sep 19 '13 at 22:48
  • All layers in the TOC, preferable by default, and preferably updated when the counts of a layer changes (for example, when a feature is added or deleted). – RyanDalton Sep 19 '13 at 22:57
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    You could probably do this with a Python addin that listens for start/end of an edit session. – Paul Sep 19 '13 at 23:50
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    I think it may be doable in ArcGIS 10.1 and 10.2 (but not 10.0) using a Python Add-In (Extension) that runs GetCount on each layer and updates the name property of each layer to include that bracketed number at each refresh. If you find/submit an ArcGIS Idea to have this option OOTB in ArcGIS Professional I would vote for it. – PolyGeo Sep 19 '13 at 23:51
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    I have done this using a script in the mxd, so I pop the code into the python window and run it to get a print of each layer with feature count. As @PolyGeo says, that could be incorporated into a Python Add-In if you want it to happen automatically (at 10.1 as mentioned). – Cindy Jayakumar Sep 20 '13 at 4:59
7

As @Paul & @PolyGeo suggested, I think trying to make this a Python Add-in makes the most sense, and I will pursue that idea later.

In the meantime, I put together code that will Add/Update the TOC Name of user-defined layers in an MXD with feature counts. For my purposes, I just created this as a GP tool that would accept individual layers via a multivalue input that accepts "Layers" in the script tool. That allows me to update multiple layers "on-demand", just updating the feature counts of those layers of interest.

I haven't come up with a way to have this run automatically, however in doing some testing of old MXD's, that may not even be desirable. If you have a lot of layers with a lot of features, it could be a slow process.

Inputbox

import arcpy

LayerInput = arcpy.GetParameterAsText(0)

mxd = arcpy.mapping.MapDocument("CURRENT")
for lyr in arcpy.mapping.ListLayers(mxd):

    #Skip over group layers, as they have no values to count
    if lyr.isGroupLayer:
        continue

    #Determine basename of the layer, without the feature count
    name = str(lyr.name)

    #Determine if the layer is in the user-defined list
    if name not in LayerInput:
        continue

    #Determine if the layer name already includes a COUNT
    if "[" in name and "]" in name:
        lpos = name.find("[")
        basename = name[:lpos-1]
    else:
        basename = name
    print "    Updating feature count in TOC name for layer: " + str(basename)
    arcpy.AddMessage("    Updating feature count in TOC name for layer: " + str(basename) )

    # In 10.1, you may be able to use arcpy.da.SearchCursor to increase the speed.
    #http://gis.stackexchange.com/questions/30140/fastest-way-to-count-the-number-of-features-in-a-feature-class
    #fcount = 0
    #cursor = arcpy.SearchCursor(lyr)
    #for row in cursor:
    #    fcount += 1
    #del cursor

    #Get the feature count
    fcount = int(arcpy.GetCount_management(lyr).getOutput(0))

    #Update the lyr.name property
    lyr.name = basename + " [n=" + str(fcount) + "]"
    del fcount

arcpy.RefreshTOC()

#Garbage collection
del mxd
  • GetCount will be faster than a cursor. What made you draw the opposite conclusion? – blah238 Sep 20 '13 at 15:52
  • My initial testing of small shapefiles showed it was faster. however, after testing on larger RDBMS layers, you are correct, GetCount was faster. I've updated the code above. – RyanDalton Sep 20 '13 at 16:46
  • Nice little tool, you should share that on the ESRI code gallery? – Hornbydd Sep 21 '13 at 15:59

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