P21 fracture intensity is incorrectly calculated in the compass plugin

[serebryakov]

Good afternoon!

I am calculating P21 fracture intensity from a dense cloud obtained from a UAV survey of a slope. According to sources P21 = sum of crack lengths/wall area. For the experiment, I took a wall fragment of 2.5 x 2.5 meters (area 6.25 square meters). I drew 2 cracks with the help of compass plugin, total length 4.9 meters. Therefore, P21 should be equal to 4.9/6.25 = 0.78. However, when calculating P21 in the compass plugin, the values are about 0.0003 (see the file in the attachment). What is the error?

[daniel]

I think it would be better to ask the author directly (Sam Thiele).

Maybe reading the code might help as well: https://github.com/CloudCompare/CloudCo ... .cpp#L2737

[serebryakov]

Thanks, Daniel, but how can I get in touch with him?

[daniel]

There's a contact section on his personal website: https://www.samthiele.science/ (at the bottom)

I'll update the wiki as well!