As part of the on-boarding process at Mapbox, Sanjay, Abhishek and me set out to map levels and types of buildings around the Mapbox office in Indiranagar with help from Maning. The general idea was to micro map using field papers to identify the number of levels in each building and also classify buildings more appropriately under building=commercial or building=residential tags instead of classifying them under the more generic building=yes tag. Identifying levels on buildings would also make the 3D map of Indiranagar vastly denser.

Armed with field papers and pens, we entered micro-mapping territory. Just before splitting and heading out by ourselves, Maning suggested using a <number-of-levels>,<building-type> code for each building, so we wouldn’t overcrowd our field papers with writing. This would mean that for a residential building with three levels, we use 3,R. Walking around, with passersby looking at us queerly was interesting to say the least!

In spite of using field papers with help from a really experienced mapper, we still had to think about a lot of things - some houses with terraces had a small outhouse constructed on one side of the terrace, which wouldn’t count as an additional level. It was the same story with residential houses that have a terrace garden with an asbestos sheet covering the garden - the garden wouldn’t count as a level. We also had trouble classifying the buildings since the floors in several buildings were equally divided between residential and commercial establishments. It was also interesting to note that the number of levels in a building is not directly proportional to the height of a building - buildings with two levels may sometimes be taller than buildings with 3 levels - which wouldn’t be represented accurately on a 3D map.

Field papers are extremely useful during the mapping process because they automatically georectify the map layer and overlay it on the satellite imagery when being imported. This is not the case in traditional mapping where one has to manually do this. This is a huge benefit because it saves time and prevents accidental errors while tagging buildings. It is also extremely easy to import field papers into JOSM and overlay them over the satellite imagery of the area being mapped.

You can see a better visualised Indiranagar by PlaneMad on overpass after our field mapping trip.

The results in 3D are available on F4 Map