geos_buffer_linestring - ObjectVision/GeoDMS GitHub Wiki

Geometric functions > geos_buffer_linestring

• geos_buffer_linestring(arc_data_item, buffer_distance, nrPointsInCircle)

geos_buffer_linestring(arc_data_item, buffer_distance, nrPointsInCircle) creates a buffer polygon around each arc (linestring) in the arc_data_item. The result is a polygon data item with the same domain as the arc_data_item.

The buffer_distance is a Float64 value that specifies the width of the buffer (on each side of the line) in the units of the coordinate system.

The nrPointsInCircle is a UInt8 value that specifies the number of points used to approximate rounded end-caps and corner joins. A higher value results in a smoother buffer but increases computation time. The minimum value is 3.

The geos_ prefix of the function name indicates that the implementation of the operator uses geos.

• attribute arc_data_item with a point value type and arc composition
• parameter buffer_distance with a Float64 value type
• parameter nrPointsInCircle with a UInt8 value type

1. The composition type of the arc_data_item needs to be arc.
2. buffer_distance must be a positive value.
3. nrPointsInCircle must be at least 3.

7.202

attribute<fpoint> buffer_geometry (road) := geos_buffer_linestring(road/geometry, 25.0, 8b);

• geos_buffer_point
• geos_buffer_multi_point
• geos_buffer_multi_polygon
• bg_buffer_linestring

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