[HOT] Admin Boundary Extraction Service

Sun Nov 8 20:30:56 UTC 2015

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Hi, Samuel:

Here you have an overpass query to get all boundary relations for all
states, LGA's and wards of Nigeria, with the admin_centre's and label
of each relation when available: http://overpass-turbo.eu/s/cxp

If you want Nigeria country boundary relation too, just change "4|6|8"
by "2|4|6|8". In case you want for example only states and LGA's, just
do "4|6", and so on.

In case you want only the boundaries for a certain state, you can use
this query (this example is for Kano state):
http://overpass-turbo.eu/s/cxt

In case you don't want the admin_centre's nor labels nodes of any
relation, you have to run a different query. This one is for Kano:
http://overpass-turbo.eu/s/cxs

Whenever possible, I advise to use area codes instead names. For
example, Niger is the name of a state in Central Nigeria, but it's
also the name of Nigerias north neighbour country: Niger.

Getting the area code is simple: go to osm.org, search for the area
you are interested in (example Niger), get the relation id we want (in
our case, let's say we want Nigeria's Niger state relation id, so we
click in "State Boundary Niger, Nigeria" link, not in "country,
Niger"), and then we copy it's id (in our example 3718384), and we add
3600000000 + 3718384 = 3603718384 to get the Niger state area code for
overpass queries: (area:3603718384)

To avoid a query to overload your web browser, instead of hitting
"run" button, click in "Export" button instead. There, go to "Query"
and then click on "compact" in the "convert to (compact) OverpassQL"
link. That will open a new window with a compact OverpassQL link.
Click on it and it will make the query and download directly in your
file system the result of the query. For example, for the last example
query (Kano state boundaries without admin_centre's nor labels), the
link is like this one:
http://overpass-api.de/api/interpreter?data=%5Btimeout%3A250%5D%3B%28relation%5B%22boundary%22%3D%22administrative%22%5D%5B%22admin%5Flevel%22%7E%224%7C6%7C8%22%5D%28area%3A3603710302%29%3B%29%2D%3E%2ErelBoundary%3B%28way%28r%2ErelBoundary%29%3B%29%2D%3E%2EwaysBoundary%3B%28node%28w%2EwaysBoundary%29%3B%29%2D%3E%2EnodesBoundary%3B%28%2ErelBoundary%3B%2EwaysBoundary%3B%2EnodesBoundary%3B%29%3Bout%20meta%3B%0A

If you need any more sofisticated query, just let us know:

Cheers,

Rafael.

On 08/11/15 12:00, Samuel Aiyeoribe wrote:
> Hello HOTties,
> 
> Please does anyone know of a service for extracting/downloading
> OSM Admin Boundary that one can fork and host myself and also
> available on github.
> 
> Looking forward to your reply.
> 
> Cheers
> 
> Samuel
> 
> 
> _______________________________________________ HOT mailing list 
> HOT at openstreetmap.org https://lists.openstreetmap.org/listinfo/hot
> 
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