Forum : Advice & Critiques

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Topic: X, Y, Z values

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Sinaya77 (Over 1 year ago)
I am trying to create a DEM using  the point cloud data extracted from Photosynth. I need to gain a little more understanding of the X, Y, Z values; what do they represent? 
I also noticed that the software flips the Z and Y and, therefore, the orientation is skewed. I was able to reverse the values but wold like to know if there is a way to control the values before exporting the point cloud data. 
Any suggestions, comments, useful tips, would be extremely appreciated!
Nathanael (Over 1 year ago)
Greetings, Sinaya,

This topic may very well answer some of your questions: Photosynth coordinate system

Mark Willis (sir_ivar) did some of the first Photosynth to DEM work that I remember seeing:

There are some useful comments from Mark and Nathan Craig in this discussion:

When the majority of photos' tops do not point upward, a correct 'up' vector cannot be calculated:
Nathanael (Over 1 year ago)
Early commentary on more full reconstruction:

You will likely be interested in improving the density of the reconstruction if you want to use it for a DEM.

See these videos to hear how the camera positions that Photosynth's sparse reconstructions provides can be used with other techniques such as multi-view stereo to generate dense reconstructions:

A community effort to connect Photosynth output to a multi-view stereo solution:

Henri Astre's PhotosynthToolkit connects Photosynth to Yasutaka Furukawa's PMVS2: Introduction: Latest update:
Sinaya77 (Over 1 year ago)
Thank you much, will be sure to look into all of your suggestions.
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