Bg_buffer_linestring

geometric-functions bg_buffer_linestring

syntax

  • bg_buffer_linestring(arc_data_item, size, nr_angles)

definition

bg_buffer_linestring(point_data_item, size, nr_angles) results in a polygon data-item with buffer polygons around each arc in the arc_data_item. The resulting data item has the same domain-unit as the arc_data_item, with composition type type poly.

The size argument indicates the buffer size.

The nr_angles argument indicates how many angles are used to make the buffer angles. More angles results in smoother circles but also in more data.

The bg_ prefix of the function name indicates that the implementation of operator uses boost geometry library, more specifically, the buffer function.

applies to

  • attribute arc_data_item with a point value-type and a composition type arc. Composition type polygon might also work but is not yet tested.
  • data-item size with a float64 value type (until version 14.11.2 argument size could only be a parameter)
  • data-item nr_angles with a uint8 value type (until version 14.11.2 argument nr_angles could only be a parameter)

since version

8.031

example 

attribute<fpoint> arc_buffer (poly, arcset) := bg_buffer_linestring(arcset/geometry, 10.0, 16b);

more examples of buffer functions can be found here: Buffer processing

see also