The past couple of weeks we’ve been digitizing building footprints from satellite imagery in advance of the “mapping party,” which is a gathering to conduct an on-the-ground survey. I’ve been getting the hang of using JOSM, the Java OpenStreetMap editor, which is great for repetitive tasks like tracing buildings.
To coordinate our activities, we tried out a tool called MapCraft to help us track which areas had already been traced and divided up ‘slices’ of the overlaid cake diagram to prepare for surveying. This was a nice way to coordinate when several people were editing Falls Church from different locations.
A group of seven of us gathered at Mad Fox Brewing in ‘The Little City’ of Falls Church, Virginia on Saturday to gather details on buildings and other points of interest in the area. We had a good mix of newbies and more experienced mappers, and were able to pair off to go into the field to collect data. Mostly we relied on paper printouts – thanks to Brian for the great preparations! – of specific sections of the area, so we were able to cover more ground in a short amount of time. A few of us also took GPS tracks and waypoints using either dedicated GPS devices or smartphones. Since the building footprints were already on OSM, it was easy to navigate with the printed maps and take notes about tags to add later (name, address, use, etc). We reconvened after an hour or so of walking around Falls Church, and spent a little time updating the features in OpenStreetMap. I regret not taking a “before” screenshot of Falls Church before we focused our attention there, but there is a definite improvement in the coverage of that area.
If you have any interest in joining a mapping party or just learning more about OpenStreetMap, join the MappingDC Google Group and come out to a future event. Ideas for next events include the Arboretum, updates to Chinatown and Georgetown, and a trip to Baltimore.