[HOT] building=hut

[Pierre Béland]

Hi Nick

At the early age of the Task Manager (jobs http://tasks.hotosm.org/project/50 http://tasks.hotosm.org/project/51), we supported a Red Cross project for Gulu and Lira. We added a lot of huts there, tracing as polygon.

In West Africa, nodes have been added in the areas where the imagery was not precised enough to detect the outbound of buildings.

 
Pierre 



________________________________
 De : Nick Allen <nick.allen.54 at gmail.com>
À : "HOT at openstreetmap.org" <hot at openstreetmap.org> 
Envoyé le : Jeudi 11 septembre 2014 9h44
Objet : [HOT] building=hut
 


Hi,

A recent post on this list led me to investigate the tag
    building=hut.

I'm not entirely sure that I remember it's history within HOT, but I
    believe many of us started using it on round thatched dwellings at
    the start of the Ebola outbreak. I've been creating a circle of the
    correct size and tagging the way as 'building=hut' in much the same
    way as we create a rectangle / polygon on a square sided structure
    and tag it building=yes. The info on the main tagging wiki at http://wiki.openstreetmap.org/wiki/Key:building shows the tag being used on an area, not a node.

I've had a quick look on overpassturbo for part of Liberia, and
    there are clusters of the tag, in some places on a node & in
    others on a polygon - on at least one occasion the node has a
    comment similar to '7 huts'.

A quick query on taginfo for building=hut;
All    832415,
Node   8113
Way 824247
Relation   55

The purpose of creating the polygon was for the clever GIS folk to
    analyse and create population estimates, when used in conjunction
    with the landuse=residential polygon which needs to be traced fairly
    closely around the perimeter of the cluster of buildings to allow
    accurate estimates of population for a village / hamlet / town
    (Something to do with area calculations). I suspect that it is still
    being used for that purpose, and will continue to do so. Also if the
    building is traced it appears on the map, but if it is a node it
    does not. On the basis you can do a more accurate calculation on the
    area from the polygon & you can't do it on a node that could
    represent an unknown quantity of buildings I think we need;
* When remote mapping an area, unless the task description says
    otherwise, create a polygon for the round dwelling and tag it
    building=hut
* To ensure our own training & reference sites, such as wiki
    pages, LearnOSM and slide shows or other materials are up to date -
    if it's wrong & you can't fix it, at least highlight it so
    someone can.

-- 
  
Nick
Volunteer 'Tallguy' for https://wiki.openstreetmap.org/wiki/Humanitarian_OSM_Team
http://www.openstreetmap.org/user/Tallguy
Treasurer, website & Bonus Ball admin for http://www.6thswanleyscouts.org.uk/ (treasurer at 6thswanleyscouts.org.uk)
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