Cartographer's Toolkit

When Franςois* claimed he had a TileMill – MapBox map up and running in 30 minutes, I had to try it out for myself. So, I spent a half day yesterday and a bit of time this morning downloading it, going through the tutorial, and then messing around with it. If you had just been trying to slap some simple point data on a map then you could have done it in close to 30 minutes for sure. For those users, the TileMill – Mapbox setup works quite well. However, I got immersed in trying to figure out as many of the capabilities as I could, so it took a bit longer. Oh, and there was also the slight problem with the export, explained below.

So first off, for those who don’t know, TileMill is an open source project by MapBox**. It allows you to upload your own spatial data, style it using CartoCSS, then export to formats like PDF, SVG, or upload straight to MapBox so that you can have MapBox serve it up for you in a dynamic webmap.

There are a lot of very enthused GIS folks who love TileMill for its great cartographic capabilities. I didn’t quite get to the point where I could enable a cool carto effect, but it does seem doable, maybe just not within a 30 minute learning time frame (or even a half-day time frame). In all, my experience was a good one, and I was sufficiently impressed to want to continue using it.

Some notes:

• If you want to do geographic manipulation to a dataset such as buffering, selecting by location, or other GIS tasks, you still have to use a GIS. TileMill is not a GIS.
• When you start a new project, the program asks you if you want to import their world dataset. This world dataset is great for small and medium scale maps. At a local, large-scale, it mocks me in cartoonish fashion. You will need your own background layer for large scale maps, or wait until you export it to MapBox, then add in their streets data (which is what I did).
• There are quirks you have to get used to just as in any program. Don’t let anyone say there isn’t a learning curve. There always is. For example, what’s the difference between “save” and “save&style”? Well, after some trial and error I realized that save&style adds the CartoCSS code to the stylesheet for you whereas “save” just adds a layer to the map without the corresponding code help.
• It still has some developer-speak in the text. For example, the Open Streets, DC example project states, “OpenStreetMap shapefile extracts provided by…” I believe the word “extracts” is meant just to show-off. But I nitpick. Similarly, it’ll help if you’re used to such language as this (found in the support area): “Does adding a ‘text-min-padding’ style to your text help out at all? I would start experimenting with values in the 10-50 range. This could also be coupled with a reduction in your buffer size.” So if you are used to point and click buttons in your GIS and you aren’t used to open source software, this will be a new way of talking, thinking, and writing for you. That’s okay. I’m just sayin’.
• The export dialog was telling me it would take 6 days to export my map. Thankfully, Dane Springmeyer (@springmeyer on twitter) pointed out that you have to set the maximum zoom level to something lower than the default of 22, with each lower zoom max representing a marked decrease in the number of tiles needing to be exported. When I lowered it to 12 it exported within a few seconds. Much better.

*In comments section of The TileMill Map Gallery post.

**It’s a mystery why the two aren’t integrated into one product.

Here’s my first mapping attempt. It uses the MapBox Streets background with colors changed somewhat, and some forest permit harvest data that I built for the Hood Canal Coordinating Council using existing state data and a custom algorithm for teasing out specific harvest areas by date. You can get information about individual harvests by hovering over the polygons. The dataset itself represents a large amount of effort in getting useable information out of a public dataset. It is nice to be able to show it off in webmap form. I can see a lot of other GIS analysts wanting to do this with their data quickly and easily.

Hover over the green polygons. These tooltips were a breeze to implement in TileMill.