zlacker

>>voxada+(OP)
I don’t really see the problem but at the same time I understand it’s not a perfect solution. I used to do geospatial work using ESRI products and Zip codes polygons are very useful because people use are often interested in things inside of zip codes especially partial 3-4 digit zip code area, but they are occasionally non-contiguous so you can end up with strange results, visually and mathematically (for example how do you find the “center” of a non-contiguous shape? You don’t).

Edit: I wanted to point out that I recall that ESRI maps used to come “out of the box” with zip code polygon layers. While I agree they are technically not polygons in the strictest sense, they often are or they are fully closed shapes or close enough to it - and even if they are missing a few nodes to make a complete polygon, whoever did the digitizing probably manually closed the loop so to speak. Remember, geospatial maps are used for many different purposes, likely none of them having anything to do with postal routes, so in that sense they are “good enough” for most purposes.

>>tempor+lg1
There actually are algorithms that compute the centroid of multi part polygons. So you can in fact find the center of a non-contiguous shape. Now, whether that centroid actually has value in a real world application, I’m not sure.