community
cancel
Showing results for 
Search instead for 
Did you mean: 

Alteryx designer Discussions

Find answers, ask questions, and share expertise about Alteryx Designer.

How to Create a Density Map Using the Grid Tool

Highlighted
Asteroid

I'd like to share how I generated a simple density map using the Make Grid tool.

density.png

 

 

In this case, I used one of the free shapefiles available through Portland Maps Open Data (it looks better if you have a single cohesive area you are plotting, but free is free!)

First, aggregate all polygons into one using a Summarize tool and then divide it into a grid. For this example, I chose a 500x500 foot grid. Then use a spatial match to overlay the original shapes and their data with the grids. Use a second summarize tool to count the number of parcels (or units, or buildings, or whatever you choose) within each grid. Then let the Reporting tools do the rest! In this case, I used the legend splitter and builder to create a custom legend that converts the values to parcels per square mile.

 

I've attached the workflow, and the data are available from the link provided within.

 density map.png

 

Alteryx Certified Partner
Alteryx Certified Partner

This is great! 

 

One of my colleagues did a 2 part series on a similar topic which I'll link to here!

 

https://www.thedataschool.co.uk/ben-davis/mapping-big-data-using-tableau-alteryx-part-1-heat-maps/

 

Ben

Meteoroid

Hi @myastarling, I am seeing an error in the Overlay tool - "A field cannot be overlayed on top of itself." Can you describe what your use of that tool should do? Also, I had to unclick "Clip to Polygons" in the Make Grid tool, possibly because of a change of default between Alteryx versions.

Meteoroid

I am also only seeing 0 parcels / m2 diamonds.

Asteroid

I'm just seeing this now -- life happened and had to step away from Alteryx Community :(
So I don't know what's going on with the original workflow I posted. I replaced it with text input with the two required fields, but different data source and it is working for me. Try this out and let me know if this works.

Meteoroid

Thank you for responding,  @myastarling. The workflow completes now although the image looks different than what appears at the top of this thread. It's still helpful. Thanks!map_different.PNG

Asteroid

yeah, I chose that one because it's a smaller file to convert to text entry (only 136 kb). Here is the workflow using the same data source as the first one. I don't know what was causing the error you are seeing though.

Labels