Posted by & filed under General FOSSGIS, QGIS.

If you even visited my lovely home town of Swellendam in the Western Cape of South Africa on, you might have noticed that the building footprints for the town are almost non-existent. Building footprints provide a valuable way to understand impacts of flood and other natural hazards, as well as being a valuable source of context information when browsing the town map. It’s Christmas holiday season here in South Africa, schools have finished exams and students have time on their hands.

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This year Linfiniti Consulting is sponsoring 3 students (from left to right: Jaocoline, Barbara and Nico in the image below) to capture all of the building footprints in Swellendam. Of course I was inspired by seeing the awesome work done by  AIFDRGFDRRACCESS and BNPB and the HOT team in Indonesia.


As well as building footprints they will also capture the building:levels and building:walls attributes so that we can in the future create a nice 3D extruded model of the towns buildings. The students are new to the OpenStreetMap project and have a lot to learn about capturing data fast and accurately, so it should be a great holiday challenge for them!

If you want to grab the current dataset for the area they are going to be working on, you can get it here (in osm format). I wrote a quick and dirty script to get the osm dump from our area and calculate how many ways each person has captured. The script is a simple python flask app. I will probably flesh it out a little as time goes by to make some pretty graphs and reports. In the mean time it just produces something like this:


JPM : 3
Firefishy : 114
uip : 1
CorliJ : 1
thomasF : 11
Chalky White : 1
Burger : 137
Sumarie : 5
Jacoline : 188
timlinux : 28
Tromilemi : 2

  • emj

    Hot tip make them learn to use the “create building” tool in JOSM.. Or pressing Q to amek things square.

  • emj

    Hot tip, if you want to create bulidings then use the “create building” tool in JOSM, it’s very fast to put down lots of rectangles.

    The Q command in Potlatch will make the buildings square but it will be hell to make all those buildings.

    • Tim Sutton

      Thanks for the tips! For now they are using the potlatch 2 editor and adding the attributes manually. Once they get a little more comfortable with the process they may switch over to using JOSM. I did introduce them to the ‘make things square’ tool in potlatch 2.

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