[gdal-dev] Converting OBJ to Geojson files with ogr2ogr

[Paul Harwood]

.OBJ is a simple object mesh  (or to put it in more traditional terms: TIN)
- it has shape but no data values and is not geolocated.

I don't think there is any driver for OGR that will read .OBJ.

You are going to problems with geolocation if you write your own. Geojson
requires that the geometries are geolocated - and in the current version
that they are in epsg:4326. That is not totally impossible - people have
been using .dxf files for gis data for decades and that format is also not
in theory geolocated. It is not a trivial problem though.

I guess I would ask the usual question .. why?

- what are you actually trying to achieve and why a GIS format like GeoJSON?

- If you have to use GeoJSON - I am guessing you are transferring some data
to something that reads GeoJSON only? In that case - can your source
produce .dxf? OGR can read .dxf.

- If you only have the source in .OBJ - what other formats can the
destination read? Although, if you only have the source in .obj, I very
much doubt any of the GIS tools like GDAL are going to be able to help you.
It just is not a format used in GIS.

It is a problem we solved in the ViRGiS projec <http://www.virgis.org>t -
since .obj is used a lot in VR. There we used an existing library to read
the .obj files - but that is in C# and I doubt that would help you.

On Tue, 1 Dec 2020 at 20:15, Andrew C Aitchison <andrew at aitchison.me.uk>
wrote:

> On Tue, 1 Dec 2020, Brandon Biggs wrote:
>
> > Hello,
> > I am wondering how to convert an obj file to a geojson file? I am using
> ogr2ogr with the command:
> > Ogr2ogr -f geojson output.geojson input.obj
> > But get the error that ogr2ogr does not have an OBJ driver. I looked on:
> > the vector drivers page<https://gdal.org/drivers/vector/index.html>
> > but am unable to find a simple obj converter. I am wondering if there is
> such a thing? I am probably going to write my own that does what I want,
> because OBJ is so simple, I was just wondering if GDAL could already do it.
>
> I've never heard of OBJ, but that doesn't mean much.
>
> If you only want a read-only ogr driver you might want to look at
>         https://gdal.org/tutorials/vector_python_driver.html
> if you would find a quick-n-dirty python quicker to write than C++.
>
> --
> Andrew C. Aitchison                                     Kendal, UK
>                         andrew at aitchison.me.uk
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