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We were given city administrative boundary data as .shp files with the permission to import those to OSM / use on

I have used the Ogr2Osm scripts to convert this data to the OSM format. I tried all three versions (old SVN, UVM rewrite, pnorman's updated version) which are linked in the Wiki.

All of them produce the same results, but when I load the data in JOSM and compare them with the existing city data (Addis Ababa, Ethiopia), the imported data seems to be shifted by 176m, 222° (I measured this by drawing a way from the point where it should be to the imported point in JOSM)

When using Ogr2Osm it produces the following output:

Detected projection metadata:

The .prj file we received has the following content:


The data was exported from ArcGIS.

What can be the source for the error? How can it be fixed?

EDIT: Same problem when I use ogr2ogr and shp2osm

ogr2ogr -t_srs WGS84 -s_srs "ESRI::subcities.prj" "subcities_converted.shp" "subcities.shp" 
perl subcities_converted.shp > subcities.osm

Semi cross-posted to Stackexchange GIS

asked 03 Dec '12, 13:00

AddisMap_Alexander's gravatar image

accept rate: 0%

edited 07 Apr '15, 09:54

As found out on GIS.stackexchange I need to specify the projection string manually, because the ogr library does not detect it properly / does not do the datum conversion:

python -p "+proj=utm +zone=37 +ellps=clrk80 +towgs84=-166,-15,204,0,0,0,0 +units=m +no_defs" inputfile.osm
permanent link

answered 04 Dec '12, 14:26

AddisMap_Alexander's gravatar image

accept rate: 0%

I think we used to have a similar problem with EPSG:27700.

(14 Aug '13, 18:52) SK53 ♦

@SK53: did you solve it the same way? Or another?

(18 Aug '13, 18:28) AddisMap_Ale...

yes I added the explicit Helmert factors (the 7 towgs84 parameters), Chris Hill blogged about it at the time (, but IIRC there were still bugs in proj4 (and therefore ogr2ogr, PostGIS) relating to WGS84 and OSGB transformations in 2011.

A useful test if you have postgis, but I expect can be done with ogr2ogr is to use a well-defined point and perform transforms between various projections to test accuracy (particularly if there is a non-porj4 transformation available for comparison, as was the case for OSGB).

(18 Aug '13, 19:36) SK53 ♦

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question asked: 03 Dec '12, 13:00

question was seen: 5,306 times

last updated: 07 Apr '15, 09:54

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum