A single-sided buffer is the polygon formed by connecting a LineString to an offset curve generated on one side of the line.
Input Line
Single-Sided Buffer (width = 30)Naturally either side can be specified, by choosing an appropriate sign for the offset distance (positive for the right side, negative for the left).
Single-Sided Buffer (width = -30)At the moment there's a bit of a limitation, in that input linework with very narrow concave angles (relative to the buffer distance) create undesirable artifacts in the generated polygon. I'm hoping that some further thinking will come up with a way to avoid this, at least in most normal cases.
This functionality is accessed by setting an appropriate flag in the BufferParameters structure:
BufferParameters bufParams = new BufferParameters();
bufParams.setSingleSided(true);
return BufferOp.bufferOp(geom, distance, bufParams);
Currently this code is in SVN. It will be released in JTS 1.12 (which will hopefully be shipping
