Bg_buffer_multi_point
Geometric functions bg_buffer_multi_point
- bg_buffer_multi_point(multipoint_data_item, size, nr_angles)
bg_buffer_multi_point(multipoint_data_item, size, nr_angles) results in a multi polygon data item with buffer circles around each coordinate in the multipoint_data_item. The resulting data item has the same domain unit as the multipoint_data_item.
The size arguments indicate the buffer circle size.
The nr_angles arguments indicate how many angles are used to make the buffer circles. More angles result in smoother circles but also in more data.
The bg_ prefix of the function name indicates that the implementation of the operator uses boost geometry library, more specifically, the buffer function.
- attribute multipoint_data_item with a point value type and composition type multipoint
- 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 20.2.0 the first argument is expected to have composition type multipoint. Passing an arc or polygon attribute is deprecated: it still works but produces a deprecation warning, and is slated to become an error in a future major version. Construct genuine multipoint geometry with points2sequence. Before 20.2.0 this operator accepted arc or polygon geometry (their coordinates were treated as a set of points).
7.413
attribute<fpoint> points (district, multipoint) := points2multi_point(point, Sequence_rel, ordinal);
attribute<fpoint> buffer_circles (district, polygon) := bg_buffer_multi_point(points, 10.0, 16b);
more examples of buffer functions can be found here: Buffer processing
- bg_buffer_point
- bg_buffer_linestring
- bg_buffer_multi_polygon
- geos_buffer_multi_point
- bp_buffer_multi_point
- cgal_buffer_multi_point
- points2sequence - construct multipoint geometry