When my CHI project shifted from database driven to my new mapping focus I had a decision to make; which mapping tool to use? There are many great tools available for free, or for limited cost, but there were a few key aspects I needed to consider.
Do the maptiles have enough resolution?
The cemetery I am studying contains just over 1,000 burials in the area of an average city block. I needed a tool that would allow the user to zoom in to the individual burial. Additionally, the tool needed to be able to either provide satellite imagery taken within the last three years (prior to that the area was a parking lot and the cars make for a busy/confusing background image). Or, if the satellite imagery was not available, did the maptiles have a scheme that made the area roads and project area easily visible?
Can it handle my data?
The geospatial data was collected using a total station. A total station is a common tool used in a variety of fields, and it commonly used on archaeological projects to survey the project area. In my case, the total station was used to map multiple points per burial, creating not only a map of overall placement but also defining the shape of each coffin. This resulted in thousands of points over a relatively small area. I needed to choose a tool that would be able to accurately render each of these points. Additionally, the information was given to me as a shape file (shp). This is where the decision on which tool to be used gets easily swayed. The two main resources I had been weighing back and forth were Cartodb and Mapbox. Although mapbox recently announced an educational plan that provides free upgraded access to a basic account for anyone working within or for an educational institution, the basic account does not allow shp files to be uploaded. Cartodb allows for a greater variety of file uploads on the free account.
Cartodb example visualization with coffins
How can I create the most user friendly visualization of the data?
This is where once again, things get tricky. Although Cartodb allows for multiple layers of the data, there is no simple way to allow a user to select which layer to view on a public visualization. The only way to do this is to combine Mapbox and Cartodb into a toggle map. This approach uses mapbox to serve the background image while calling Cartodb for the layers. This is what I’m currently working on, and hopefully very soon I’ll be able to share my hopeful success.
To see a working example of this integration with the toggle map check out this tutorial.