Building own CRS

Question

I have a set of polylines which are described by a project-specific, local coordinate system. I would like to find a more or less accurate way of reprojecting these polylines to EPSG:28992. I have been looking into building my own custom projection with pyproj but it looks like this is quite complicated.

I'd rather have an easier way. However, if there isn't, would anyone give me some pointers on how to start building my own coordinate system such that I can reproject my locally defined polylines to an EPSG based coordinate system like EPSG:28992?

What does this project-specific coordinate system look like? If it is cartesian, you could probably use just a vector translation and a rotation (if it is not already North oriented) — Berend, Apr 08 '22 at 14:08
Yes. It is cartesian. I think some stretching might be needed as well, so I'm not sure if a simple translation+rotation would be sufficient. Now looking into this approach https://gis.stackexchange.com/questions/175642/georeferencing-vector-dataset-in-qgis — user32882, Apr 08 '22 at 14:11
With translation I meant an addition and a multiplication (in other words: moving and stretching), so that should work — Berend, Apr 08 '22 at 14:17
How can I do that for multiple polylines? Could you point to something from the literature? I have only found transformation matrices for one point coordinate at a time (2x2 matrix) — user32882, Apr 08 '22 at 14:23
As per the [help/behavior] please do not include chit chat like thanks in your posts. — PolyGeo, Apr 08 '22 at 20:48

score 1 · Answer 1 · answered Apr 08 '22 at 14:48

I ended up using ogr2ogr which works reasonably well for what I'm trying to achieve. This answer provides some further detail.

In addition to running the command line tool, I had to "Assign projection" to the resulting vector layer in QGIS. Since I am using a projected coordinate system I didn't have any issues.

Building own CRS

1 Answers1