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Aggregating while keeping attribute

March 23 2009 | 0 comments
Categories: ArcGIS Methods, Map Data

I've been trying to simplify a world map by aggregating close polygons together before simplifying my lines (so small island could be joined to the mainland instead of being just erased), but all the countries became like dissolved. Is there a way to aggregate my data while keeping all the countries (i.e. with the attributes)?


Mapping Center Answer:

Well, that's not quite possible, at least in one step.  The first thing I would do is Dissolve by Country name, producing multi-part output.  The expectation there is that the data are modeled in a useful way.  For instance, The Canary Islands, in addition to having an attribute that has the name of each island, also has a field with country name, Spain, in this case.  That way you could Dissolve on the country attribute, and have a multi-part polygon with mainland Spain, and with additional parts that included the Canary islands (among others).  

Next, I would do the simplification--it sounds like you already have your method.

Then, to get the attributes back, use the Multi-part to Single part tool on the simplified result.  Then do a Spatial Join such that the original polygons get joined to the simplified result.  The spatial Join will assign the names from the original to the simplified. 

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