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  1. I want to georeference TCP flight map of Spain.

It says: Lambert Conformal Conic Projection Standard Parallels 41dg 20' and 46dg 40' Convergence factor 0.69491

QGIS does not offer this CRS and even Mr. Google did not offer me CRS number.

In QGIS I found only Madrid 1870 LCC EPSG2062 that I do not consider correct and I do not have any idea how to modify it for the purpose of georeferencing. It will be exported to UTM30 anyway.

  1. Which way is the correct one? a) export layer & save as with changed CRS b) conversion (translate) or c) warp (reproject)
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  • What are "TCP Flight Maps"? How old is this map? Can we see it? Have you looked at writing your own WKT or PROJ string to define this coordinate system? It should only need the two standard parallels and an earth ellipsoid model (I think the convergence is a factor of these). You should be able to do a projection georeference with this once you've got a few reference points.
    – Spacedman
    Dec 2, 2023 at 12:43
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    The map: maps.lib.utexas.edu/maps/tpc/txu-pclmaps-oclc-22834566_f-1c.jpg . Georeferencing should not be a problem but it will require CRS anyway. I looked at creating PROJ but at the moment it goes behind my abilities. Dec 2, 2023 at 12:58

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Both can be correct, but consider these:

  1. Setting up the correct parameters for the projection, anyone can use export to any different projections and everyone will get the same result.
  2. Using warp you have to have the coordinates of some points in the source and the target CRS. It gives a solution only between the source and target CRS. Repeating the warp using different common points/coordinates you will get a bit different result.

I suppose export into a different CRS is more general solution.

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