Question: I found a this great 3D population density map created by Time Magazine:
I have been trying to recreate this map look, but have had little luck.
Here are the steps I have been taking:
1. Using Transportation Analysis Zones with population data, I created the centroids of each zone.
2. Using Spatial Analyst, I used the kernal density tool to show population density of the centroids.
3. I overlayed the centroids on a TIN in ArcScene and extruded by the New raster created by the kernal density tool.
- Now I have “peaks” similar to the Time Magazine map, but it looks more like mountains then the clean spikes in their map.
Do I need to do some type of post processing or is there a better way of trying to recreate such a map?
Answer: On your first step, it looks to me like they just used City Points and then threw them into one of the Spatial Analyst’s interpolations tools; I’d start with IDW. That will give you a surface that you’ll need in ArcScene or ArcGlobe. It will be symbolized and used as it’s own base heights.
The only extrusion in this map is about a 5 mile extrusion on the states, and the states were also drawn on top as well.
A quick test in ArcScene showed me that I could use US States extruded to a height of 20,000 meters. Then I displayed states as another layer, but this time I set the base height to 20,500 meters. Then I would set the base height of the population surface to 20250, and on the Base Heights tab, it will obtain it’s elevation from a layer (itself). You may have to adjust the population numbers (like add 20250 or normalize them if they’re spiking too high).
I’ll play around with this tonight and see what I come up with in terms of a more detailed set of steps and if I’m on track I’ll put it up on the Mapping Center blog as I’ve had a few people ask about making this sort of map lately, so it will be a good thing to publicize. Thanks!
Formerly a Mapping Center Ask a Cartographer Q & A.