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Contour in Rasterize non-continuous

Posted: Tue May 12, 2015 4:49 pm
by palmitoale
Hello,

I have found a bug in the contour function in Rasterize (very powerful btw, especially for treating non-height fields).

When I treat topography data, some iso-lignes are not continuous (see attached picture).
Bug CC.jpg
Bug CC.jpg (107.04 KiB) Viewed 1883 times
If I demand closer lines, it looks worse.
Bug CC2.jpg
Bug CC2.jpg (120.03 KiB) Viewed 1883 times
The void pattern looks funny so I think it might be a problem in the algorithm...

Also, If I take the same cloud, and take off every point above a given heigth (one of the non-continuous isoline for instance), and try to get the cloud contour, the algorithm fails also (even with different maximum segment length) ? Is the same algorithm involved ?
BugCC3.jpg
BugCC3.jpg (18.13 KiB) Viewed 1883 times
Thank you for your reply,
I can send the cloud if you want to run some tests...

Ps : the clouds is regular in the problematic area (no funny point, mesh looks fine, etc.)

Re: Contour in Rasterize non-continuous

Posted: Wed May 13, 2015 7:22 am
by daniel
Indeed this hole is quite strange... it's probably a bug of course. I would be very interested by your cloud indeed (and the parameters that would reproduce the bug if they are not the default ones). You can send it to me at 'cloudcompare [at] danielgm.net' (replace [at] by @).

The contour algorithm is not the same (at all). And I changed it recently so hopefully this second issue should be fixed by those modifications.

P.S.: both tools were introduced in CloudCompare thanks to the LNHE laboratory at EDF R&D