Hi Matthew,
Looks like we missed your post somehow; apologies! I downloaded some example GIS .shp files from the HUD COC (Continuum of Care) site here. It appears that they're broken up into individual polygons, so for California there are forty-four (44) separate files. Fortunately, in Tableau, so long as they're identical in data structure/format, we can UNION those files together. So no problem there.
The other part is more tricky and you'll need zip codes that are mapped to a lat/long value. You can get a set of them from here (just attribute the site for use): https://simplemaps.com/data/us-zips
So in the example (attached), I joined the US zips (by MAKEPOINT() calculation) and the GEOMETRY from the two files and did a full outer join using the older join method, not the newer Relationships model:
Then go to Worksheet 1 and drag over Geometry from the .shp file. Then create same MAKEPOINT() calc again for the zip code points. Drag that over to the canvas/view. You'll see a new Map Marks drop zone highlight up in the upper left corner of the map. Just drop that calc on that drop zone and the zip codes should populate automatically with a circle for each point (lat/lon). Thereafter we can use the new INTERSECTS function to help determine if the zip codes fall within a particular HUD COC or not. Simple boolean function:
Intersects?
INTERSECTS([Geometry],[Zip Code Point])
And, we end up with a nice map of zip code points that fall within the boundaries of the HUD COC:
That could've also been a spatial buffer as well:
So, a variety of things. Hope the attached helps point the way. Best, Don
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