2 Replies Latest reply on Jul 28, 2016 12:48 PM by Patrick A Van Der Hyde

    Overlaying multiple maps based on different sources into one

    Nataliya Sysenko

      Hi All!


      There is a necessity to overlay two maps of the same geographic unit, but with different data points. Or, at least, it would be also good to have them both on one dashboard, but to syncronize zooming.

      The main challenge here is that:

      1. One map is created with a help of postcodes (and therefore generated coordinates of longitude and latitude). It contains piecharts for each postcode.

      2. Other map is created with a help of exact ("pure") coordinates of data points (in my case, gas pipelines created as "lines" on the map)


      When I try to apply dual axis or common filtering, it does not function because:

      1. When I try to join datasets based on postcodes (that may be common union-ing link from both datasets), Tableau substitutes generated coordinates for the first map with "pure" coordinates for the second and does not recognize the first map anymore. I guess, it is so because coordinates for postcodes not found in the second dataset are simply recognized as null values.

      2. I can't join datasets based on coordinates, as coordinates for the first map are in fact absent in dataset (they are automatically generated by Tableau based on postcodes)

      3. Even when I have corresponding postcodes for the second map, I can't create a map of gas networks, because I need to depict lines, so I need to use exact data points and unite them into line.


      I have already studied the problem and reviewed the following discussions:


      Mapping polygons and points together dual axis

      Combining two maps in to one view?

      Re: overlaying two sets of data points on the same map


      However, they did not help.

      Perhaps any ideas on how it is possible to use one map as a background for other and zoom them instantly?

      I would be grateful for any idea.

      Thank you.