Cartographic Skills Module 11: 3D Mapping

This week we studied 3D mapping in Cartographic Skills as well. For the first section of the lab, we went through an ESRI training course on the basics of visualizing 3D data in ArcScene, including data types, how to set base heights and extrude features, and how to manipulate lighting. For me personally, the hardest part about adjusting to 3D scenes is how to navigate them successfully, but that's probably due at least in part to the fact that I'm currently working on a laptop with just a trackpad. I assume you get better control with a mouse!

For the rest of the lab assignment, we worked with data on building footprints in downtown Boston. Given the building footprints and a LiDAR dataset of the same area, we extracted height information for the buildings from the LiDAR file by taking a series of sample points and then using the average z value for each building footprint as the height for that building. With that data, we could display the buildings in 3D in ArcScene. Then we exported that layer as a KML file and opened it in Google Earth. The end result looked like this:

3D mapping is useful for urban planning, simulations, modeling industrial activity, visualizing environmental changes, or any application where it's helpful to view terrain in a similar way as it appears in the real world. It can also be helpful in viewing multiple datasets simultaneously, whereas the same map in 2D might get too crowded or complex to be useful. 3D maps can also be used to display data with z-values whose meaning isn't inherently spatial. For example, things like temperature, population, and property values can be visualized in 3D.

Some advantages of 3D maps are their versatility and the ability to explore complex spatial relationships, as well as to simulate viewsheds/lines-of-sight and what an area would look like at different times of day or year. However, care has to be taken to display height or depth data accurately, or to make it clear what information is being presented in the case of data like property values, as it could be easy for the viewer to misunderstand what they're seeing. It can also be hard to see certain features if the map covers a large geographic area or if some features block others from view. This problem is somewhat avoidable if the viewer has the ability to zoom in and out and navigate around the map, but if the map must be viewed outside of ArcGIS, exporting multiple static views from different angles or scales might be necessary to show a complete picture of the data.