“Hey guys, we can support ArcGIS online basemaps, right?”
“Oh yeah, definitely, we use OpenLayers, there must be a layer for that”

Azavea is no stranger to contributing to open source projects, so when we learned that OpenLayers was lacking full support for the newer ArcGIS basemaps, I knew I had a job to do. The community had been looking for this functionality for over 2 years, and still didn’t have a solution. You might say that developing tools for crime fighters would be exciting and rewarding, but it is also nice when something you wrote has the potential to be used everyday by a community you value.

We quickly discovered that a few partial solutions existed, but something was ever so slightly off, those layers weren’t performing in all the configurations we needed. We had a head scratching situation, we had tiles, we had a standard format, but it seemed like they wouldn’t let us get the calibration just right. Finally the eureka moment hit when we discovered that the server was not being entirely literal with it’s capabilities, and that they were actually subtly changing as the zoom level changed! Once we knew that, it was a simple matter of overriding some base code, recalibrating and extrapolating the extent, and we were set!

Fast forward to today, and we’ve peer-reviewed the layer internally, added documentation, multiple examples, and unit tests, and we submitted a patch to the community about a month ago. Although it isn’t officially in the trunk yet, we already have word from a new friend in Spain that the layer has helped him with a project!

I’m excited that this layer could help more developers and organizations take advantage of the great cartography offered by Esri while using the powerful OpenLayers platform. So please keep your fingers crossed while we go through the approval process once again, or checkout the patch and try it for yourself, and let us know what you think. It can support out of the box ArcGIS.com basemaps, local ArcGIS servers, and raw file caches produced by ArcGIS.

Thank you to those who helped (Jeff, Aaron, Zwarg, and Robert), and to those who helped online and in the community, Thanks! Also thanks to Esri, who just made their ArcGIS map tiles available for free to everyone!