[Qgis-user] Planetary (Venus) coordinate reference systems

[Gabriel De Luca]

Hi,

  I think that it is the main canvas trying to reproject all layers to a
common (but not related to any Earth's) CRS.  As if the datum
transformations between these systems were not defined, and the absence of
the WGS-84 pivot was insurmountable.

  In my opinion, the most convenient thing to do is to disable the
"on-the-fly" projection of the main map. In the project properties, CRS
tab, checking the option: "No CRS (or unknown/non-Earth projection)".

  In this way, the canvas becomes a kind of "universal-unitless 2D
Cartesian system". All the geometries of the layers will be displayed in
the coordinates that are stored in their vertices, and the rasters
according to their matrices of geotransform. In fact, it can contribute to
a better understanding of coordinate reference systems.

  The only things that are disabled are on-the-fly reprojection on the main
map and maybe ellipsoidal measurements. All other functionalities must be
available.


Regards,
Gabriel

El vie, 10 nov 2023 a la(s) 18:49, Diaz, Tony A. via QGIS-User (
qgis-user at lists.osgeo.org) escribió:

> I’m trying to help a student understand projections and trying to load in
> a Venus global map data. When they try to align different maps with the
> same projection, or even change projection, a consistent error message  "No
> transform available between XXXX and Custom CRS” keeps occurring.
>
> Any tips or ideas would be helpful,
>
>
>
> Tony
>
> Caltech
>
> Pasadena, CA
>
>
>
>
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