API Technical Discussions

Polygon, block group and census data

I would like to get census block group data for various groups that overlap with a polygon map overlay. If I can get the block groups and need say the number of Chinese of ages 18 to 34 in those block groups then how do I do a JavaScript query to get them?


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  1. Comment
    Phillip Thomas

    According to the Decennial Summary file 1 documentation ( http://www.census.gov/developers/data/sf1.xml ) you appear to be talking about the variables "P012D007, P012D008, P012D009, P012D010, P012D011, and P012D012"

    Also according to the geography documentation we can limit based on block groups. ( http://api.census.gov/data/2010/sf1/geo.html )

    And so our final link would look something like:


    Also this query works on my end, provided I substitute the withheld key with a valid one. As far as overlaying the data on a map, that is not knowledge I have available to me at this current moment.

    Comments on this comment

    1. Comment
      Community Member ( Idea Submitter )

      Thank you!!

      What about looking at say Chinese of ages 18 to 34?

    2. Comment
      Phillip Thomas

      Please refer to the first sentence of my previous post. I selected the variables within Decennial Summary File 1 that satisfies that requirement (they appear after the get= in the query as well).

    3. Comment
      Community Member ( Idea Submitter )

      Thank u but that first link is a mess of data with no instructions saying how it is organized??

    4. Comment
      Community Member ( Idea Submitter )

      Never mind ... My bad!!

  2. Comment
    Phillip Thomas

    For those who need help breaking down the link at this point:

    Host name, API sub-folder (this triggers our api to parse the following data).


    This portion refers to the DataSet/Instance pair (without both, it's difficult to determine what number you want back)


    This determines what variables to retrieve (required, must exist within the variable documentation for the API)


    Geography, all currently available data sets require this to return proper numbers


    The reason for this is two-fold, allowing us to limit users, as well as providing us with information as to how many people are using what dataset.


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