[jts-dev] singlesided and flat cap buffer issues

[Robin Winkelmann <robin.winkelmann@xxxxxxxxxxxxxxx>]

Hello,

I'm working with
jts and want to use the buffer function for the validation of a Geometry.

Task: We have
a Linestring, that is part of the boundary of some Geometry with dimension
2 and the Geometry itself. Now we want to validate, whether or not the
Geometry could be part of the strip to the specified Linestring and if
not, work out which parts are not inside. We'd like the accepted area to
be perpendicularly cut at the ends of the Linestring.

My simple idea:
Generate the singlesided buffer for that Linestring and see, which parts
are not inside that buffer (with difference function: difference between
input geometry and buffer geometry)
My problem: The
JTS buffer function (singlesided, but also flat cap) sometimes produces
geometries, I can not understand.
some examples:

LINESTRING (760
180, 863 179.5, 862.5 190.5), single sided buffer with distance 50,

LINESTRING (652
234, 600.5 202.5, 736 203.5, 674.5 234), singlesided buffer with distance
1000

LINESTRING (657.5
257, 639 234.5, 764.5 234.5, 747 255.5), singlesided buffer with distance
275 and higher provide a singlesided buffer that's not including any point
of that Linestring!

If you have any
hints for me with using the JTS buffer or someone has a hint for my task,
I would be very thankful.
Best wishes,
Robin Winkelmann