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'free form' extent rectangles

November 13 2009 | 0 comments

Lets say I have a series of land parcels which are generalized/dissolved by a particular attribute field such that there are multiple parcels in each group.

I want to identify these groups on a map but have something more enhanced than just symbolizing them by unique values. The idea of creating multiple extent rectangles is cumbersome and depending on the spatial location would create large rectangles which would unnecessarily overlap each other. I had thought about buffering these, but in cases you still do not achieve a continuous outline of each group.

One could just free-form a polygon for each group, I suppose, but it I'm trying to devise way in which the software generates the outline.

I guess what I'm trying to achieve is identifying the extent of each group. Could then smooth and buffer that extent to achieve the cartographic effect I'm after.

Mapping Center Answer:

One idea to achieve the effect you are looking for is to symbolize your dissolved parcel groups by Categories > Unique values where the Value Field is group.  Then, you can assign each group a different color outline to distinguish one from the other. 

You can also buffer the group to get an outline that contains all of the parts within the group, but as you point out, you may encounter problems of overlapping lines. Buffers can still work for placing the extent around each group if you use a different color outline for each group. In doing so, you will create visual seperation of each individual group by the buffered extent line color so even if there are two overlapping lines, it is clear which extent belongs to which group.

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