first welcome to Tableau
see the article by Sarah Battersby on spatial joins - it covers yor case
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Thanks for the quick reply!
It helped me with joining the two different files, but it is still quite unclear to me how I can link the number of a given community area with the respective community area name. Do I need to rename all the community areas manually? Or is there a way for Tableau to recognize the community area number as community area name?
And if renaming everything is the only option, how do I then make Tableau recognize the geographic format of the variable, which allows me to utilize the GeoJSON file, so I can map the crime data in the respective community areas?
I can't see the data after the Join - so don't know how you connected them - see Sarah's memo starting about 2/3rds of the way down under the heading below
The 2018.1 and beyond easy dual axis method:
it is there that she is placing points on shapes with a dual axis map
If you were to hover your mouse cursor over the red exclamation point in the Data Pane Window in Tableau Desktop, you'll see a message that describes the error. Like so:
It says the issue is your data is structured as a STRING (ABC/TEXT) on one side of the JOIN from your Chicago Crime Data table and as a WHOLE NUMBER (1,2,3,4,5, etc.) in the other table (.shp file). Tableau cannot join on different data types.
In this case, I changed the STRING to be recast as an Integer (Whole Number), so that it would recognize the JOIN between the two columns. I used [Area Numbe] field.
You had a good start and were on the right track though...please see below screenshots for context as to how to correct the issue.
Your data will be INNER-JOINED thereafter. Hope it helps! Thx, Don