[HOT] Why the HOT obsession with low quality buildings in Africa ?

Jean-Marc Liotier jm at liotier.org
Mon Jul 2 08:24:52 UTC 2018

Active in Senegal and Mali, I have noticed that changesets tagged with
tasking-manager HOT projects produce very large numbers of buildings.
Those buildings appear to be of very low quality. I wonder: who uses
this data ?

If it is only necessary to assess that people live there, then a
landuse=residential is sufficient

If it is necessary to count the number of dwelling units to infer
population, then a node is sufficient (maybe along with an attribute to
discriminate single or multi-tenancy)

If the geometry is actually necessary, then I wonder if anyone is
satisfied with those semi-random shapes that, with some optimism, may be
identified as being in the vicinity of actual buildings (most of the

Enthusiastic contributors expend an awful lot of effort in flooding the
map with low-quality buildings. I have seen ruins, building parts,
walls, vague shadows on the ground, rubbish heaps, market stalls, cars
and trucks all tagged as buildings - and I'll charitably keep from
commenting on the geometric quality of those that attempt to map actual
buildings (and I'll leave aside the issue of HOT leads requiring the use
of outdated imagery such as Bing instead of ESRI World in Bamako). Is it
the most useful way to channel the energy of inexperienced contributors

I often find myself wishing that HOT leads introduce them to
Openstreetmap through Osmose quality control rather than by churning out
buildings like demented stonemasons trying to reach their weekly quota
of gamified task-managing !

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