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Is it possible to rotate about a point when selecting an output coordinate system?

Hi there,

I’d like to be able to open a DEM generated by Pix4d into software that uses a local grid. I have the following information to assist:

Conversion MGA94(AHD) to Grid
This conversion involves both a horizontal transformation and vertical shift.
For Levels: AHD + xxxx
For Horizontal Transformation
Scale factor = xxxx
Rotation = x(D) x’ x" About E xxxx N xxxx
delta E = xxxx
delta N = xxxx

One issue that I can see is rotating about a point so I can’t use the ‘Site Calibration Parameters’.
I see that I can use a ‘Known Coordinate System’ from a .prj file which I’ve looked into but couldn’t come across an example which does what I’m after.

If anyone could point me in the right direction or provide an example .prj file that rotates about a point that would be awesome!

I’ve read this article https://support.pix4d.com/hc/en-us/articles/202559979-How-to-obtain-or-create-a-prj-coordinate-system-syntax-file which looked promising but falls short on the rotation issue.

Thanks :slight_smile:

Hi Benji,

I am not familiar with how to define the rotation in a .prj file and would suggest trying the Site Calibration implemented in Pix4D.

It can be computed using a project with image geolocation in a known coordinate system (e.g. WGS84) and with GCPs in an arbitrary coordinate system (local grid). It is recommended that the image geolocation and the GCPs are of high accuracy in order to obtain an accurate estimation of the transformation parameters.

This way you will be able to translate, rotate and scale the resutls:

Best,