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I have a set of data that corresponds to zip code, and I'd like to turn that into a map. From what I've gathered thus far, zip code shapefiles are difficult to find and work with due to the fact that they're not polygonal. However, I found an old version of the US Census's 5-Digit zip code tabulation areas on the Census website that I think will do the trick.

I'm currently using Magic Maps in an attempt to do keep this mapping process as non-technical as possible, and I was able to import map the outlines of the zip codes quite easily. However, when it comes to incorporating my data into this map, I'm a little lost. I was able to plot the points in the appropriate location on the map (very simple copy/paste process thanks to Magic Maps).

However, the data shows up as a point on the map, and I'd like it to fill the entire zip code instead. See here for an example. I'm new to GIS and shapefiles and dbfs and whatnot, so correct me if I'm wrong, but I'm guessing this is due to the fact that the zip code "tag" in my csv data isn't connected in any way to the dbf file, so it's not actually connected to the contour that shows up on the map. As a result, the software just places a point on the map that's more or less in the center of the zip code, which is in no way connected to the shapefile that I downloaded from the Census website. Is this correct? And if so, is there a way that I can add my data to the dbf file? Or, is there a better way of going about all of this?

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up vote 4 down vote accepted

There are a couple of things to look up. Geocoding, and intersect. I have never used magic maps so I can't say if it has this capability but from your sample map I would guess it does.
1. If you don't have location data for your csv, then you can use geocoding.
(It sounds like you already mapped your points so I assume this is not the case). The wording of your question title led me to think in this direction first.
2. Using a join (if MM) does have that function is what you want to do.

Where zip code 73701 is in your csv that is joined to the polygon with 73701 in its atributes. These are then called primary and foreign keys.
You can then change the symbology of the polygon with the value of any field in your foreign table.
If your csv has more than one value for any single object in the spatial table you will have. To decide how to treat that. Most GIS software perform an inner join easily. Spatial join and outer joins are needed if a one to one relationship is not present.

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Join did the trick! It was relatively easy to find in Magic Maps once I knew what I was looking for. Thanks for your help! – Kyle Wurtz Feb 13 '13 at 13:20

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