Xmp coordinate system

Development Asset Creation
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1

I have a georeferenced project and am trying to process the camera pose data (xmp). But the position appears to be in global/earth coordinates:

<xcr:Position>-2350552.62084975 4871158.33186044 -3369155.24637428</xcr:Position>

But looking through the forum it looks like its usually in local coordinates. This is how I’m exporting the mesh so I need them to also be local. I’m assuming this is because my project is georeferenced, but is there a setting I’m missing that controls the output coordinate system for XMP? Ideally I don’t want to convert it back as this would introduce some precision error. Maybe theres a way to disable/remove the project georeference data?

2

Steven hello!

You can disable prior pose in Image properties. In that case RC will estimate pose in Local coordinates if i remember right.

3

Hi Vladlen,

Which setting in particular do you mean? I see the ‘prior pose’ group when I select the image, but nothing that seems to disable it. I played with some of the settings Relative pose, Absolute pose, Absolute coordinates but they didn’t seem to make any difference to the exported .xmp position

4

Sorry, i misunderstood your question.
Do not clearly understand what you want to do. Just clear georeference or export georeferenced.

But check this:
Workflow -> Settings -> Project/Output coordinate system
probably can help you.

5

I can probably explain better. When I generate a model, the points are all relative to a local origin somewhere in the center. So I end up with nice small positions like X=100m, Y=90m etc. But the xmp position uses the center of the earth as the origin, so the numbers are huge (which makes it less accurate), and they don’t match up with my model. I just noticed that the numbers posted here were generally nice small numbers, so I thought there might be a setting

6

Sorry, still not clear.

What i have on XMP:
<xcr:Position>3.22765820450667 -53.9876082462076 70.7805008256276</xcr:Position>

This is because i always set Prior position to unknown for iPhone made images that have GPS data (useless)
And use Local coordinates in Project/Output coordinate system.

Also XMP export have several options you can play if needed.

7

Hi Steven Watts

in WORKFLOW->SETTINGS->COORDINATE SYSTEM you can set PROJECT CS and OUTPUT CS ( output CS can be changed as much as you want )

If want have local coordinates ( local1 ) and you have GPS info or etc then just set local1 as project ( so all GPS info will be transformed to local coordinates) and set local1 as OUTPUT CS or just set GRID PLANE.

If want keep your GPS or etc Coordinate system then you just need to set proper PROJECT CS and all data will be converted to the project CS.

8

Sorry for the delayed response. Just tried it using various combinations of project and output coordinates systems, but nothing seems to affect the xmp position. Do I need to rebuild or something to apply the change?

Where did you mean to set ‘grid plane’? I know and use this when exporting the mesh, but xmp export doesn’t have this option unfortunately.

9

Hi Alex - did you have any luck with this?

 

I am trying to set xmp coords - but the do not appear under the coordinates in ‘prior pose’

 

thaks

10

I noticed same thing… 

This is image position automatically taken from image EXIF info.

This is image position information from exported .xmp file (you can see that they are automatically transform to different coordinates system)

and this is image position from re imported image with assigned .xmp file

And that’s the final results from this operation.

My intention was changing distortion parameter and principal point coordinates in .xmp file, but CR automatically messed up image position.