Getting building data at a coordinate

Question

I would like to be able to click on a building on a map and get the polygon that comprises the building at the clicked coordinate.

I looked into overpass api and tried the following:

<query type="way">
  <around lat="51.0566036" lon="13.7181033" radius="30"/>
  <has-kv k="building"/>
</query>
<union>
  <item/>
  <recurse type="down"/>
</union>
<print/>

If I choose a large radius I get too many buildings. If the radius is too small I don't get any buildings. Using bbox-query did not help.

I also tried coord-query, but I was not able to construct a meaningful query. The necessary query syntax seems to be different.

Is there a better approach at hand? Even withouth overpass, I have just to look into it.

score 3 · Answer 1 · answered Jul 20 '14 at 16:28

A similar requirement was discussed in this GitHub ticket. At this time, Overpass API doesn't calculate area information for buildings, which would be required for is_into work. However, you could set up your own Overpass API instance and adjust the area creation rules to also include buildings. For a small area this should be even feasible on your local machine.

Please also check all links in the GitHub ticket I mentioned. It includes a number of additional pointers which may be relevant to your problem.

Caveat: The performance and space implications of calculating areas for buildings on a world wide scale are unknown, respectively not fully tested yet.

Thanks for elucidating! At the start I don't want to set up my own instance. I've described what I'll do first in my comment to MaM's answer. — Amelse Etomer, Jul 21 '14 at 10:58

score 3 · Answer 2 · answered Jul 17 '17 at 10:21

There is a Python solution using gis_geometrics [1] and overpy. This Python program finds the building at LAT,LON. Put it in the same directory as gis_geometrics.py:

import overpy
from gis_geometrics import OSM_Polygon, Overpass

api = overpy.Overpass()
building = OSM_Polygon.getPolygonByCoords(api, LAT, LON)
if building is None: print("No building found.")
else: print(building.wayId)

With the way id you can make an overpass request to find the polygon coordinates.

[1] https://github.com/timojuez/home/blob/master/mylib/gis_geometrics.py

score 2 · Accepted Answer · answered Jul 20 '14 at 14:57

2

What you try to realize is a 'reverse geocoding'. To avoid the mentioned problems (AFAIK) usual implementations use an arbitary radius and then test the resulting shapes once more if they contain the desired position.

answered Jul 20 '14 at 14:57

MaM

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Thanks! I'll try the following: Testing with a small radius (50m) and if it fails using a large one (500m). After a few queries I'll reassess and see if I could optimise by using a different radius to find a good ratio between number of api calls to transfered data. – Amelse Etomer Jul 21 '14 at 10:56

Getting building data at a coordinate

3 Answers3