geos.GEOSCoverageSimplifyVW ⇒ GEOSGeometry ⏏
Operates on a coverage (represented as a list of polygonal geometry with exactly matching edge geometry) to apply a Visvalingam–Whyatt simplification to the edges, reducing complexity in proportion with the provided tolerance, while retaining a valid coverage (no edges will cross or touch after the simplification). Geometries never disappear, but they may be simplified down to just a triangle. Also, some invalid geoms (such as Polygons which have too few non-repeated points) will be returned unchanged. If the input dataset is not a valid coverage due to overlaps, it will still be simplified, but invalid topology such as crossing edges will still be invalid.
Kind: global property of geos
Returns: GEOSGeometry - A collection containing the simplified geometries, or null on error.
| Param | Type | Description |
|---|---|---|
| input | GEOSGeometry | The polygonal coverage to access, stored in a geometry collection. All members must be POLYGON or MULTIPOLYGON. |
| tolerance | number | A tolerance parameter in linear units. |
| preserveBoundary | number | Use 1 to preserve the outside edges of the coverage without simplification, 0 to allow them to be simplified. |
geos.GEOSCoverageSimplifyVW_r ⇒ GEOSGeometry ⏏
Operates on a coverage (represented as a list of polygonal geometry with exactly matching edge geometry) to apply a Visvalingam–Whyatt simplification to the edges, reducing complexity in proportion with the provided tolerance, while retaining a valid coverage (no edges will cross or touch after the simplification). Geometries never disappear, but they may be simplified down to just a triangle. Also, some invalid geoms (such as Polygons which have too few non-repeated points) will be returned unchanged. If the input dataset is not a valid coverage due to overlaps, it will still be simplified, but invalid topology such as crossing edges will still be invalid.
Kind: global property of geos
Returns: GEOSGeometry - A collection containing the simplified geometries, or null on error.
| Param | Type | Description |
|---|---|---|
| extHandle | GEOSContextHandle_t | - |
| input | GEOSGeometry | The polygonal coverage to access, stored in a geometry collection. All members must be POLYGON or MULTIPOLYGON. |
| tolerance | number | A tolerance parameter in linear units. |
| preserveBoundary | number | Use 1 to preserve the outside edges of the coverage without simplification, 0 to allow them to be simplified. |