| Computes the buffer of a geometry, for both positive and negative buffer distances.
In GIS, the positive buffer of a geometry is defined as
the Minkowski sum or difference of the geometry
with a circle of radius equal to the absolute value of the buffer distance.
In the CAD/CAM world buffers are known as offset curves.
In morphological analysis they are known as erosion and dilation
The negative buffer of lines and points is always empty geometry.
Since true buffer curves may contain circular arcs,
computed buffer polygons can only be approximations to the true geometry.
The user can control the accuracy of the curve approximation by specifying
the number of linear segments used to approximate curves.
The end cap style of a linear buffer may be specified. |