You may have noticed that the Oakland Crimespotting map changed its appearance this week. We’ve switched to OpenStreetMap so that the public can contribute their own local knowledge and make Crimespotting a better service.
The most important thing to say about the new map design is that it’s made of geographical data from the OpenStreetMap project, the free world map that anyone can edit. It helps Oakland by providing a way for users of Crimespotting to share their own local knowledge with the broader OpenStreetMap community to help generate an excellent, extensive map of the city. Examples of such knowledge include: parks, schools, commercial districts, businesses, government buildings, walking paths, cycle routes, and other street-level information that might otherwise fall through the cracks of a map provider such as Google or Microsoft.
We like and use Virtual Earth maps in particular, but these maps were originally created to suit the purposes of transportation, such as commercial drivers interested in directions. The two maps above are examples of the difference. The first is a Microsoft Virtual Earth map in the style that we featured here previously, and it provides accurate, reliable information about streets and major geographical features. What it’s missing can be seen on the second, which has markers for public schools, hospitals, and train stations throughout the city. These landmarks are important for a site like ours, primarily built for local residents interested in learning about neighborhoods.
Zooming in to the Uptown area around Broadway and Grand Ave. shows how a variety of local businesses and points of interest have been added to the map to provide local context and an understanding of the street from a ground level view. All of the churches, schools, and cafés seen in this second view were added by participants with a local interest in the neighborhood:
OpenStreetMap is primarily a collection of geographic data, and encourages interested users to create their own renderings for specific purposes. We’re using a visual style called “Pale Dawn”, which we designed for a CloudMade, a company developing commercial uses of the extensive OpenStreetMap data set. The visual design is low contrast, and developed especially for the presentation of layered, dense data such as crime reports. Geographical details are plainly visible, but are more subtle. Streets and highways, for example, don’t visually collide with the red, green, and blue crime report markers that we place over the surface of the map. It’s easier to see what’s important and use the map as background for the information we’re presenting on it.
The easiest way to describe the project is by an analogy to Wikipedia: participants in OpenStreetMap are the authors of a free worldwide map. They can use a variety of editing tools from graphical editors that work in a browser to let you trace aerial photographs of streets and buildings, to simple notification systems for marking mistakes on the map, all the way to sophisticated GPS-based tools that let users map entirely new parts of the world from scratch.
OpenStreetMap has an excellent introduction on their website.
We’re excited to be trying something new. Oakland Crimespotting is rooted in a very local concern with our neighborhoods, and we’re hoping that using maps made by real people who live in Oakland will add an extra level of usefulness to the project. If you’re of a technical bent and see something that you think should be changed, we’re really hoping you take a moment over at OpenStreetMap to add to the project. We’ve also started a blog, so it should be easier to keep track of what we’re up to. And as always, please feel free to mail us at info@crimespotting.org.
More about OpenStreetMap
There are two ways you can help fix mistakes and get new information into the base map. If you see a problem, the simplest thing to do would be to make a note of it for someone else to fix, using the OpenStreetBugs service to point out and describe the issue. If you feel confident using graphical tools in the style of a drawing program such as Adobe Illustrator, you may find it easiest to simply make a change yourself. A guide to Potlatch, the OpenStreetMap editor, can be found here:
If you’re interested in a more hands-on introduction to editing the map, OpenStreetMap’s Bay Area Community Ambassador Sarah Manley runs frequent weekend mapping parties.