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

[Paul Harwood]

I guess the OP can answer for themselves but I am curious since I cannot
see anyway that Cityxxx would facilitate the conversion of an .obj into
GeoJSON ?

On Wed, 2 Dec 2020 at 12:49, Clay, Bruce <bclay at infoscitex.com> wrote:

> Take a look at CityXml / CityGml and CityJson.  There is partial support
> at least in GDAL based on web searches.  Also some support for QGIS through
> a plugin
>
>
> Bruce
>
>
> ________________________________
> From: gdal-dev <gdal-dev-bounces at lists.osgeo.org> on behalf of Paul
> Harwood <runette at gmail.com>
> Sent: Wednesday, December 2, 2020 5:31 AM
> To: Andrew C Aitchison
> Cc: gdal-dev at lists.osgeo.org
> Subject: [EXTERNAL] Re: [gdal-dev] Converting OBJ to Geojson files with
> ogr2ogr
>
> .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<
> https://usg02.safelinks.protection.office365.us/?url=http%3A%2F%2Fwww.virgis.org%2F&data=04%7C01%7C%7C0da679eff03c4694022308d896ad7f40%7C3430c5de5e6f4f9d9d9690e985038b58%7C0%7C0%7C637425019296346911%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=P2rkx2BIsKJ0GPY3EdGesGO%2B9Az%2FTB5s0f9YMRkH%2FH0%3D&reserved=0>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
> <mailto: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<
> https://usg02.safelinks.protection.office365.us/?url=https%3A%2F%2Fgdal.org%2Fdrivers%2Fvector%2Findex.html&data=04%7C01%7C%7C0da679eff03c4694022308d896ad7f40%7C3430c5de5e6f4f9d9d9690e985038b58%7C0%7C0%7C637425019296346911%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=YlMoWYX%2FArELUfRlhGmaqSd8H%2BQeyhJKoWz2FZSQoNM%3D&reserved=0
> >>
> > 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<
> https://usg02.safelinks.protection.office365.us/?url=https%3A%2F%2Fgdal.org%2Ftutorials%2Fvector_python_driver.html&data=04%7C01%7C%7C0da679eff03c4694022308d896ad7f40%7C3430c5de5e6f4f9d9d9690e985038b58%7C0%7C0%7C637425019296356903%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=ulnrpqd06IeuubvWwEkSSFhsPUWFw9rsfdYfGWf0zis%3D&reserved=0
> >
> if you would find a quick-n-dirty python quicker to write than C++.
>
> --
> Andrew C. Aitchison                                     Kendal, UK
>                         andrew at aitchison.me.uk<mailto:
> andrew at aitchison.me.uk>
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