skeletonize's result is different when changing the world shape

[litingzhen]

Describe the bug 1.8.1， with the same geometry, use skeletonize to this geometry，but the result is different when changing the world shape.

To Reproduce Steps to reproduce the behavior:

         shape_file myshp<- shape_file("xxxx"); 
     geometry shape<-envelope(myshp)+500;
         create geoshape from:myshp;
     list<geometry> skeletons <- list(skeletonize(last(geoshape )));
     write length(skeletons);

Expected behavior when I change the shape (500-->1000 )，the skeletonize result should be same.

Desktop (please complete the following information):

• OS: win10
• PC Model:
• GAMA version: 1.8.1
• Java version: 1.8
• Graphics cards / Display system:

[litingzhen]

the shape_file is freespace.zip

[ptaillandier]

Hi,

I can't test the script because some files with the shapefile are missing (.shx, .dbf and .prj files)

Cheers,

Patrick

Le dim. 14 nov. 2021 à 20:31, litingzhen @.***> a écrit :

the shape_file is freespace.zip https://github.com/gama-platform/gama/files/7533814/freespace.zip

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[litingzhen]

Sorry, all in this zip. freespace_allinone.zip e

[ptaillandier]

Hi,

I tested with GAMA 1.8.2 and we have the same issue... but I am not sure that it is possible to fix this issue as the skeletonization depends on the triangulation: the differences are due to rounding problems in the floats (slight difference in the coordinates). There is not much we can do about it.

Note that if we define a not null value for the tolerances of triangulation and of clipping, the results are similar in all cases: skeletons <- (skeletonize(last(geoshape ),0.1,0.1));

Cheers,

Patrick

Le lun. 15 nov. 2021 à 14:15, litingzhen @.***> a écrit :

Sorry, all in this zip. freespace_allinone.zip https://github.com/gama-platform/gama/files/7536568/freespace_allinone.zip e

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[AlexisDrogoul]

I think that there is nothing we can do automatically here. The arguments to skeletonize are largely enough to cover this error. I'm closing the issue then, but feel free to open a new one in https://github.com/gama-platform/gama2/issues