I have a vector layer with the definition of the blocks of the state of NY, and I have another vector layer with the definition of the group blocks of the state of NY. They are two different vector layer (shapefiles).

I also have a CSV table with some extra information (population) with the field GISJOIN, and I can join this csv file with one vector layer, the block vector layer (that have the same field GISJOIN).

How can I do the join with the other group block vector layer?

My goal is to have a csv file compatible with the group block vector layer.


1 Answer 1


It sounds like you're trying to join population data (CSV) intended for census blocks (SHP) with census block groups (SHP).

If that's correct, I think you've got two options.

If you want to stick with your current data arrangement, you could do as @Mapperz suggested, and perform a spatial join. I would do this join based on the block centroids being within the block group. Here are some tips for doing this with QGIS:

I would recommend a second option, however, that makes the sort of spatial operation described above extraneous. And that is to just download the population data intended for block groups and do the join with the CSV table on that layer.

  • It is something like that. Really, It is not the population data, but race data. I have the csv file of the blocks of the race data and I want the race data for the group block. They don't exist to download in group block! Commented Oct 11, 2016 at 18:40
  • You might find what you're looking for at nhgis.org. I did a quick peek and found race available at the block group level for the 2010 census. Otherwise, you might be stuck with option #1: spatial join.
    – rumski20
    Commented Oct 12, 2016 at 20:05

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