[gdal-dev] GDAL 3.x and AutoCAD GeoTIFF georeferencing

[Kirk Waters - NOAA Federal]

My apologies on typing the link and adding an 's' to the name. Should be
ftp://ftp.coast.noaa.gov/tmp/kwaters/autocad_issue.zip

Thanks for the tip on the configuration option! I agree about the ideal
solution.

Kirk


On Thu, Oct 7, 2021 at 3:59 PM Even Rouault <even.rouault at spatialys.com>
wrote:

> Kirk,
>
> the download link doesn't work.
>
> GDAL 3.3 will use geotiff 1.1 conventions by default when a compound CRS
> is used. You may try adding -co GEOTIFF_VERSION=1.0 to force GeoTIFF 1.0.
>
> When reading a GeoTIFF 1.1 file, GDAL will report the compoundCRS. For
> GeoTIFF 1.0 files, you need to specify --config GTIFF_REPORT_COMPD_CS YES
> (see https://gdal.org/drivers/raster/gtiff.html#configuration-options)
>
> Autocad users should ideally report that to their vendor so they add
> support for GeoTIFF 1.1 (or maybe the issue is not much the change of the
> version number, but that we stripped down the formulation of geokeys to the
> minimum to avoid specifying things twice and the risk of contradiction)
>
> Even
> Le 07/10/2021 à 21:41, Kirk Waters - NOAA Federal via gdal-dev a écrit :
>
> Hi all,
> I'm finding a change in georeferencing between GDAL 2.4 and 3.x that
> results in AutoCAD not being able to figure out where on earth a geotiff
> should be. I don't have AutoCAD, so I'm reliant on what my downstream users
> are telling me. These are elevation Tiffs, so they do have a vertical
> component to the SRS and that may be where the difference lies. I know it
> isn't up to GDAL to solve AutoCAD's lack of standards adoption, but I'm
> wondering if anyone has come across this and if there's a way to force the
> outputs that AutoCAD will read.
>
> Two small files are included in a zip file at
> ftp://ftp.coast.noaa.gov/tmp/kwaters/autocad_issues.zip. One
> (Job640647_ches_coned.tif, made with GDAL 2.4) has georeferencing that
> works in AutoCAD, the other was made with GDAL 3.3.1 and has georeferencing
> that fails. Both were made with gdal_translate -a_srs EPSG:3582+6360 with
> the difference being the version of GDAL. They are not the exact same
> location on the ground.
>
> If I look at the files with listgeo, the older version has more tags and
> includes the horizontal and vertical units. With gdalsrsinfo, the newer one
> shows the more complete COMPOUNDCRS that includes the vertical component.
>
> I'm hoping I don't have to go back to GDAL 2.4 for AutoCAD users. If
> anyone has come across a solution before, I'd love to hear it.
>
> Thanks,
>
> Kirk Waters, PhD                     | NOAA Office for Coastal Management
> Applied Sciences Program      | 2234 South Hobson Ave
>                                                  | Charleston, SC 29405
>
>
>
> _______________________________________________
> gdal-dev mailing listgdal-dev at lists.osgeo.orghttps://lists.osgeo.org/mailman/listinfo/gdal-dev
>
> -- http://www.spatialys.com
> My software is free, but my time generally not.
>
>
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