cartagen.simplify_angular

cartagen.simplify_angular#

simplify_angular(geometry, angle=10.0)#

Simplify a line or polygon by removing vertexes with small angles.

This algorithm, proposed by McMaster [1], eliminates vertices that represent very small turning angles (< 10 degrees). This prevents rounding filters from destroying sharp curvatures, granting the resulting geometry a ‘manually generalised’ characteristic where significant bends remain prominent.

Accept Multi geometries. If a polygon is provided, it also applies the thinning to its holes using the same parameters.

Parameters:

  • geometry (LineString, MultiLineString, Polygon, MultiPolygon, LinearRing) – The geometry to thin. If an open line is provided, the endpoints are preserved. If a closed ring or polygon is provided, the angles wrap around.

  • angle (float, optional) – Turning-angle threshold in degrees. Vertices creating an exterior angle below this limit will be iteratively removed. Default is 10.0.

Returns:

LineString, MultiLineString, Polygon, MultiPolygon, LinearRing – Thinned geometry of the same type as input.

See also

simplify_douglas_peucker

Simplify a line or polygon using a distance-based selection.

simplify_lang

Simplify a line or polygon using a look-ahead distance-based selection.

simplify_li_openshaw

Simplify a line or a polygon using a regular grid.

simplify_raposo

Simplify a line or a polygon using an hexagonal tessellation.

simplify_reumann_witkam

Simplify a line or polygon using a directional distance-based selection.

simplify_visvalingam_whyatt

Simplify a line or polygon using an area-based selection.

simplify_wang_muller

Simplify a line or polygon using a bend-reduction method.

simplify_whirlpool

Simplify a line or polygon using an epsilon-circle based selection.

References

Examples

>>> line = LineString([(0, 0), (1, 0.1), (2, 0), (2, 5)])
>>> simplify_angular(line, angle=10.0)
<LINESTRING (0 0, 2 0, 2 5)>

(Source code)

../_images/simplify_angular.png