2020-07-02 15:03:16 +10:00

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{
"name": "offset_curve",
"type": "function",
"groups": ["GeometryGroup"],
"description": "Returns a geometry formed by offsetting a linestring geometry to the side. Distances are in the Spatial Reference System of this geometry.",
"arguments": [ {"arg":"geometry","description":"a (multi)linestring geometry"},
{"arg":"distance","description":"offset distance. Positive values will be buffered to the left of lines, negative values to the right"},
{"arg":"segments","optional":true,"default":"8","description":"number of segments to use to represent a quarter circle when a round join style is used. A larger number results in a smoother line with more nodes."},
{"arg":"join","optional":true,"default":"1","description":"join style for corners, where 1 = round, 2 = miter and 3 = bevel"},
{"arg":"miter_limit","optional":true,"default":"2.0","description":"limit on the miter ratio used for very sharp corners (when using miter joins only)"}],
"examples": [ { "expression":"offset_curve($geometry, 10.5)", "returns":"line offset to the left by 10.5 units"},
{ "expression":"offset_curve($geometry, -10.5)", "returns":"line offset to the right by 10.5 units"},
{ "expression":"offset_curve($geometry, 10.5, segments=16, join=1)", "returns":"line offset to the left by 10.5 units, using more segments to result in a smoother curve"},
{ "expression":"offset_curve($geometry, 10.5, join=3)", "returns":"line offset to the left by 10.5 units, using a beveled join"}]
}