Unbuffered geometries using negative distances

[kamo]

Hi!

I've been extensively testing some problematic issues with the buffer function using PostGIS. Seems that in some cases interior rings are not being used to perform the

inner buffer generation although for most of the cases rings are correctly used.

I was able to assemble some xml files from my test data (used a simple

script to generate this files based on PostGIS' results) and I ran them through the XMLTester for GEOS and also for JTS. The results can be observed in the attached files. Seems like there is a high error rate when using st_buffer (for both inner and outer rings) and that JTS has got a more conservative error detection approach (?) compared to GEOS.

I originally filed this error in PostGIS' error tracking system but they recommended to post the test results here.

[kamo]

XML test files and results

[strk]

as of r2504 JTS and GEOS results are the same (3 failure, 97 successes)