13 maps in 13 days: Gretchen Peterson

Sending off the year 2015, we present to our readers the mapmakers who contributed their work to the 2015 GeoHipster calendar.


Gretchen Peterson

Q: Tell us about yourself.

A: I am the author of the cartography books Cartographer’s Toolkit: Colors, Typography, Patterns and GIS Cartography: A Guide to Effective Map Design. I am also the co-author of QGIS Map Design, to be released in early 2016 by Locate Press. I reside in Colorado and actively tweet via @petersongis on cartography.

I am a Cornell graduate in the natural resources field, and can still be found spending part of the work week absorbed in data analysis and mapping for the greater environmental good while reserving the rest of the work week for broader mapping endeavors, which includes keeping up on the multitude of innovative map styles coming from all corners of the profession.

Q: Tell us the story behind your map (what inspired you to make it, what did you learn while making it, or any other aspects of the map or its creation you would like people to know).

A: This map is just a snippet of a world-wide basemap created specifically to be placed underneath users’ data layers to provide geographic context. To that end, the color palette is muted and, though the product for which it was originally created was discontinued, it still works nicely as a stand-alone map.

My team created it using OpenStreetMap data pulled down with imposm3 via a custom mapping JSON file to pull down the specific bits of OSM that we wanted. Osmosis was then used for processing, and at one point we even had a good working changeset procedure to keep the map continuously updated.

The styling went through several iterations to arrive at this look and feel, and was then continuously tweaked as the project evolved. This is pretty typical when designing a webmap that has to be incorporated into a website’s overall aesthetic, which itself evolves through time. The surrounding site and the webmap must have a design alliance achieved through continuous dialog.

Q: Tell us about the tools, data, etc., you used to make the map.

A: The map was tiled with GeoServer and the styles were written out in SLD. When I began the project I wasn’t familiar with SLD, so I used the GeoCatBridge product to get some good initial SLDs created with the kinds of filters that I needed, and then proceeded to develop them as straight-up SLD from there. Getting proper RegEx statements going is always a challenge, but we also got that going in the end to get the right features and labels to show.

As far as labeling goes, a font was used that had enough character sets to style all the languages we wanted to support world-wide so that labels wouldn’t show up as empty glyphs.

From beginning to end I’d say the project took about 3 months. There’s definitely some robust infrastructure that’s needed for these huge OSM world-wide pulls, especially if you want to set up a dev environment to try out new styles with — as we did — while still running the full map in production for existing users.

'San Francisco base map' by Gretchen Peterson
‘San Francisco base map’ by Gretchen Peterson