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Is there a way to apply an arbitrary coordinate translation to a layer in QGis 2.8.2? I have some data sets that are in a truncated coordinate system, and I need to shift them by a certain amount to line up with the real world coordinate system.

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    I believe you can do this in the CRS definition by tinkering with the parameters.
    – ed.hank
    Nov 4 '15 at 18:12
  • I thought about doing this, but the CRS screen doesn't let me edit the proj+ line. I'll keep looking...thanks! Nov 4 '15 at 19:11
  • I would try affine transformation. v.transform seems to do it and then there should be this plugins.qgis.org/plugins/qgsAffine. However, I can't install the latter with the plugin manager. But I am not sure what you mean with arbitrary. Affine is not arbitrary. For more flexible "rubber sheet" warping with warping vectors I would use OpenJUMP.
    – user30184
    Nov 4 '15 at 19:26
  • There is a plugin called 'vectGeoref' that might help. (I think it is experimental.) I've never used it so I'm not putting this forward as an answer.
    – nhopton
    Nov 4 '15 at 20:50
  • I am working on a site where mine coordinates are state plane coordinates minus 800,000 in X and minus 2,300,000 in Y, so in order to use layers generated in mine coordinates, I need to shift the layer by +800,000 in X and +2,300,000 in Y in order for them to be overlaid properly with layers that are in actual state plane coordinates. Thank you all for your suggestions! Nov 5 '15 at 16:32
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In QGIS, you can take the CRS definition, go to Settings -> Options -> Custom CRS, and paste it there as a new CRS.

If it is a projected CRS like transverse mercator, lambert or albers, you can set or modify the projection with a false Easting +x_0 or false Northing y_0.

For geographic CRS with degrees as units, you can modify the +towgs84 parameters.

Having saved your custom CRS, you can Rightclick -> Set Layer CRS to apply it to your datasource.

Using a plugin for affine transformation might be easier, see

  • AffineTransformations
  • Vector Bender
  • vectorgeoref

plugins. You might have to enable experimental plugins in the settings tab to see and install them.

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