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I am in need of processing a photogrammetry file to point cloud then apply analysis module by using Python. Using meshlab, I have managed to export xyz file of my model then converted to txt file, so I can easily access and plot data using matplotlib.

After exportation, I realised that z components of the files seem to be clustered, which I mean that when I imported the file to python script and ran it z range was very limited, almost looking like the whole thing was compressed.

When I opened the exact same file on meshlab it seemed fine. Since the xyz file has 6 columns and I used only the first 3, I am suspecting that to be the cause but I'm just not sure what the problem is. I have used all the elements on first 3 columns which I'm sure that they are x y and z components. I attached the pictures for comparison, hope it helps.

Here's what the text version of xyz file looks like (there are more than 100000 rows really).

-4.985628 -4.780845 338.250854 -0.017581 0.003231 1.949280 

-3.285533 -4.431212 342.610321 -5.846900 1.895777 0.458446 

-3.165349 -4.922605 338.837158 1.874727 2.051935 -1.483359 

-3.215735 -4.802375 340.320557 0.734949 1.160611 -3.693605 

-4.378054 -4.010946 338.241455 0.105474 0.526878 6.178342 

-3.421478 -4.800171 339.638275 5.733778 0.596651 -0.693699 

-3.258153 -4.573445 342.971680 -4.019710 -3.309187 0.685745 

-3.177556 -4.822459 340.345184 0.145794 -4.698930 -2.289058 

-3.182967 -4.490508 342.649597 2.286415 4.822868 -0.867586 

-2.500194 -4.949868 339.606293 3.396397 -2.453691 -3.078794 

-3.351677 -4.784164 340.290802 -0.003160 -6.204160 -0.270498
S.L. Barth is on codidact.com
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C.Lee
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  • It may look like that there is a problem with z axis range, but it isn't. I have tried changing z axis range multiple times and it did not turn out to be the right answer. – C.Lee Nov 30 '16 at 05:30
  • Could you provide the code you are using forma both converting xyz to txt and processing un python? – David de la Iglesia Dec 05 '16 at 09:16
  • Thanks for your interest David, but I have figured out that there was a problem with the origin of point cloud, adding unnecessary height to all z values and screwing up with the scaling of the whole system. If you are interested I can still provide you my code, but the problem is solved. Thanks though! – C.Lee Dec 07 '16 at 00:24

1 Answers1

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Problem solved, it was just with the axis setting as well as origin point. All the points were way above the origin, resulting the structure to look compressed. As long as you keep in mind of the origin and scaling, it works well.

C.Lee
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