When I try to merge my household data file in a .dbf format with my shapefile by using key variable, I get the following error message:

Chosen table merge key field IL contains undefined or duplicate values. Key fields must contain valid unique values.

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Because, in my dbf file, provinces have several observations. However, my shapefile has just name of the provinces. So how can I merge these two files in GeoDa?

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    May 24, 2016 at 17:00

1 Answer 1


I think the error message tells you pretty clear what the problem is!

Just make sure that both files have an attribute column with unique values.

Edit at least on of your files and change keys in column IL for example by adding the number 1000.

IL (old)    IL (new)
1           1001
10          1010
11          1011
12          1012
13          1013
...         ...

When your are sure that both files have unique keys you can merge them again.

Hope that helps!

If you have in both files the same key you might not looking for a merge but a join of your data!

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