I am conducting a buffer analysis on a vector feature class of Urban-Wildland Interface zones, and am trying to calculate the total areas of each particular classification of interface area.

As I walk through this question, elements that represent column attributes will be [framed], and data will be indicated with (parentheses)

For example... Buffer A's [municipal_name] is (Charleston), and features [Interface_Type] (HighDensity_Interface); (HighDensity_Intermix); and (MedDensity_Interface) areas.

Buffer B's [municipal_name] is (Amherst), and features Interface_Type; (HighDensity_Intermix); and (LowDensity_Interface) areas.

  1. I have successfully isolated the two buffer areas using the "Identify" function. The vector data based on the original Urban-Wildland interface feature class is somewhat "checkerboarded" (metaphorically speaking) given the diversity of interface areas within each.
  2. I then added a new field and "calculated geometry", populating the new field with [Area] data
  3. Now, each metaphorical "square" in the "checkerboard" has an area calculated. For example 6 of the individual "squares" in (Amherst) have now had their (HighDensity_Interface) [Area] calculated, and so on with the other [Interface_Type].

Since (Amherst - Buffer B) and (Charleston - Buffer A) are in the same feature class, I am having a difficult time summarizing the areas of each interface type and aggregating those calculations based on [municipal_name].

Is there a way to do this in ArcMap? Or should I begin analyzing my tables in a separate statistical tool, such as SAS?

I tried doing a basic "dissolve" function, but that unites (HighDensity_Interface) across both buffers, which is not what I want.

  • Is there a way to split this new "dissolved" feature class based on [municipal_name], separating results from (Amherst) and (Charleston)?

I may have just done things backwards... time for some more poking.

  • Could you add snapshot(s) please? – fatih_dur Nov 21 '15 at 12:25
  • I'd try the Summary Statistics tool perhaps with municipal_name as the case field for one of your steps. – PolyGeo Nov 21 '15 at 12:49

It sounds like you need to use either the Summary Statistics tool (Analysis Toolbox/Statisics Toolset) or the Dissolve tool (Data Management Toolbox/Generalize Toolset), depending on whether you just want a related Table or a related Feature Class as your output. You would need to put both the [municipal_name] and the [Interface_Type] fields into the Case Field portion of the Summary Statistics tool or the Dissolve field of the Dissolve tool. If you only want areas that actually touch each other to combine, use the Dissolve tool with the Multi-Part option unckecked so that it generates single part features. The Dissolve tool will also eliminate duplication of areas wherever two buffers of the same municipal_name/Interface_Type overlap, while the Summary Statistics tool will not.

The table/feature class that is created cannot initially be joined to your original data, since you would want to create the join based on two fields. I have created a tool in this Blog post that will add a single unique key field to both the original feature class and the Summary/Dissolve output that represents each unique value combination from the two Case/Dissolve fields. Using that new field you can create a Join between the original feature class and the summarized output. That way you can determine an original features' percentages of the total area for a given municipal_area/Interface_Type combination.

I am not sure why you had to calculate an Area field, since an Area field is automatically created and maintained for feature classes in a geodatabase. The Summary field set up of the Summary Statistics and Dissolve tool can use the built-in Area field of a feature class to create a Sum value in either tool output so you can use that Sum in a Join. While you would have to create and calculate an Area field for a shapefile, the field names you listed make no sense if you are using a shapefile, since field names are limited to 10 characters in a shapefile.

  • Excellent! Yes, I was able to find a solution using the "Dissolve" tool. Following your steps... 1. Input the field with the buffer areas "Identified" into the "Dissolve" tool 2. Check boxes for [municipal_name] and [interface_type] 3. Leave "Create Multipart Features" box checked – VectorFiend Nov 26 '15 at 0:38

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