Feature request #204

Rasters with multiple projections in a project are not handled gracefully

Added by Brendan Morley - about 13 years ago. Updated almost 10 years ago.

Status:Closed
Priority:Low
Assignee:ersts -
Category:Projection Support
Pull Request or Patch supplied: Resolution:invalid
Easy fix?:No Copied to github as #:10263

Description

If a map canvas has 2 or more rasters added to it, in different projections, only the first projection is honoured. Subsequent projections are silently disregarded.

In the case of a UTM projection being added first and a Lat/Lon projection added second, the "zoom to layer extent" of the second layer does seem to work OK but then the layer viewport is selected using UTM coordinates, which is way out of range therefore resulting in no image being generated for the second layer.

Suggested course of action for a fix:

1. Warn the user if a raster layer is about to be selected that is incompatible with the project projection.

2. WMS layers can have their projection selection filtered down to match the project projection.

3. Longer term, introduce the GDAL Warp function to do raster projection conversion on-the-fly.

History

#1 Updated by Giovanni Manghi almost 10 years ago

  • Resolution set to invalid
  • Status changed from Open to Closed

QGIS do not support raster on the fly reprojection. Nevertheless I agree that 1) should be introduced. If I'm not wrong it was already suggested somewhere here in the trac or in the wiki in the qgis "wish list".

Meanwhile now gdal warp is now available trough the "gdal tools" plugin, that hopefully will become "core" as it was the case for the "ftools" plugin for vectors, that now is part of QGIS. Now that this tool (gdal warp) is available natively for qgis why not thinking using it to implement 1)?

If the loaded raster is recognized to not have the same crs of the project then use the gdall warp tool to same a copy of the raster with the project crs and load it into the canvas.

I don't think that 2) is that important: once the connection to the wms server is established it shows in what crs the layers are available...

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