[Qgis-user] error loading tiff layer

[Gabriel De Luca]

El vie., 31 de ene. de 2020 a la(s) 08:10, Humberto Nel Florez Ramos (
hnflorezramos at gmail.com) escribió:

> regards.
> I could not load a layer in tiff format. The error that qgis shows is:
>
> "No transform is available between Unknown CRS: ENGCRS [" PCS Name =
> unnamed ", EDATUM [" "], CS [Cartesia ... and Unknown CRS: GEOGCRS ["
> unknown ", DATUM [" unknown ", ELLIPSOID [" WGS 8 ... .
> No coordinate operations are available between these two reference systems
> ".
>
> The file has a reference system, which is magna-sirgas from Bogota (3116),
> I have tried the magna-sirgas (3116) project, and wgs84 (4326) showing the
> same error.
>
>
Humberto,

ENGCRS is a WKT2 Engineering CRS keyword. So the file seems to be a GeoTIFF
with a Engineering CRS.

While EPSG:3116 Magna SIRGAS is a projected CRS.

Engineering (or Topocentric) CRS may be converted to a Geocentric CRS as
described in the Section 2.2.2 of the Geomatics Guidance Note 7, part 2
Coordinate Conversions & Transformations including Formulas [1].

I think that QGIS doesn't have support for this kind of CRS, but I think
that PROJ does. So maybe you can find a pipeline string for the conversion
from the Engineering CRS to the Projected CRS with projinfo, and then
transform the GeoTIFF file with gdalwarp program (-ct parameter for the
pipeline string).

Once you have the GeoTIFF file reprojected to SIRGAS, you will have no
problem loading it into QGIS.

If you want to copy the WKT2 string, we can try to find the pipeline string
to convert it to EPSG:3116.


Kind Regards.
Gabriel


[1] Page 99 of http://www.epsg.org/Portals/0/373-07-02.pdf
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