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I have some raster and vector data in one coordinate system and a WMTS services on another coordinate system. To go from on coordinate system to another i need to use custom transformation parameter and to go through 3 different coordinate systems and 2 custom transformation parameter because there is no transformation parameter for going from coordinate system 1 to coordinate system 3.

I can re-project data so they can fit together but i want to use it on the fly because i don't want to re-project data everytime.

For maps to fit together the workflow of projecting data is:

Coordinate system 1 (EPSG:28404) (vector or raster data) -> custom transformation parameters(EPSG:28404 to EPSG:32634) -> Coordinate system 2 (EPSG:32634)-> custom transformation parameters (EPSG:32634 to EPSG:3127 )-> Coordinate system 3 (WMTS service) (EPSG:3127)

So the input coordinate system is EPSG:28404 and the destination is EPSG:3127 but you should go through EPSG:32634 so that the maps can fit together.

Is there any way to do this in QGIS on the fly projecting?

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  • QGIS has on-the-fly CRS transformation. I don't see any reason why it shouldn't work for your data. If it doesn't work, update your question with a specific description of the problem.
    – csk
    Jun 21, 2017 at 17:05
  • What are the methods used for the 'custom transformation parameters'? That is, are they GeoCRS/datum transformations converting from Pulkovo 1942 to WGS84 then WGS84 to ETRS89 or are they polynomial transformations converting directly between UTM 34N and GK zone 4?
    – mkennedy
    Jun 21, 2017 at 19:55
  • Based on Arcgis it used the "coordinate frame" method with seven parameters tx,ty,tz, rx ry rz, ppm.
    – Shefqet LULJA
    Jun 22, 2017 at 8:13
  • Yes, QGIS has on the fly CRS transformation but it can use one custom transformation at time, as you can see from my scenario i go through 2 custom transformation parameters
    – Shefqet LULJA
    Jun 22, 2017 at 8:14
  • I have found the solution in Arcgis but can't find a solution in QGIS. In Arcgis it uses Composites Transformation which combine different transformation parameters for projecting data from one coordinate system to another.
    – Shefqet LULJA
    Jun 22, 2017 at 9:39

1 Answer 1

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In ArcGIS, first you have to configure the transformation from one coordinate system to another using custom transformation parameter for every coordinate system (1,2,3) like in the scenario of the question.

And then at least in Arcgis 10.2.2 (not tried on other versions) it automatically calculate the transformation from Coordinate system 1 to Coordinate system 3 and uses a composite transformation for projecting the data like in the figure below:

enter image description here

It combine both custom transformation parameters and project the data directly from Coordinate system 1 to Coordinate system 3 and you don't have to go through Coordinate system 2.

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