Handling of Raster Input Data without CRS

[Matthias Wocher]

Hi guys,

my proposal is rather to be understood as a wish. The EnMap-Box 3 does not allow rasters to be loaded without a defined CRS or actually it does but it asks several times for a CRS it does not have. When a raster is loaded the EnMap-Box asks again for a CRS when I want to assign it to a map view. Also, ad hoc RGB color assignment is not working in this case.

Often I receive quickly processed raster data sets and rarely people take care about CRS assignment for preliminary results. Would it be possible that the EnMap-Box 3 allows for raster data to be loaded without CRS for quick data plausability checks?

Thank you very much!

[Benjamin Jakimow]

Could you provide a (very small) data set for this?

[Matthias Wocher]

I added a small ENVI.bsq with missing map info and coordinate system string. The Enmap-Box accepts the file but asks several times for a CRS both when loading the raster and when displaying it.

[Benjamin Jakimow]

Such CRS requests are handled in the QGIS API. They can be avoided by specifying a default CRS in QGIS Settings->Options

[Benjamin Jakimow]

and here is the screenshot how to change the default CRS in QGIS.

I recommend using a projection with metric units and not something like EPSG:4326 WGS84. In case of degree units QGIS assumes you pixels have a GSD of 1x1 degree.
In that case images could exceed the legal boundary of the default CRS. For example, an image with more than 90 lines would have its lower boundary at > 90 south - which obviously is not allowed in case of EPSG:4326 and might cause errors if a QgsMapCanvas tries to reproject the image into another CRS.

Using a UTM projection instead should be the better way.

[Benjamin Jakimow]

pulled qps updates resolves issue #274 - EnMAP-Box will not ask for any CRS resolves issue #281 - EnMAP-Box opens QgsSubLayerDialog to select requested sublayers

Signed-off-by: benjamin.jakimow [e-mail]

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