Request for documentation
From pull request qgis/QGIS#65596
Author: @nyalldawson
QGIS version: 4.2
Expose concave hull of polygons functionality
PR Description:
This PR:
- Exposes the GEOS "concave hull of polygons" functionality for use in PyQGIS
- Allows polygon (and line) feature input for the Concave Hull by Feature algorithm. Previously a user would have to first extract vertices from the polygon to calculate the concave hull from the points, but that approach ignores the interior of the polygons.
- Adds a dedicated "Fill gaps between polygons" algorithm:
Unlike the standard Concave Hull algorithm, a Concave Hull of Polygons is a (possibly) non-convex polygon containing all the input polygons. The computed hull fills the gaps between the polygons without intersecting their interiors. It strictly follows the outer boundaries of the input polygons, allowing you to fill gaps between them without distorting their original shapes.
It is particularly useful for cases such as generalizing groups of building outlines, creating 'district' polygons around blocks, or
removing gaps and joining disjoint sets of polygons.
See https://lin-ear-th-inking.blogspot.com/2022/05/concave-hulls-of-polygons.html?m=1 for more details
Commits tagged with [need-docs] or [FEATURE]
"[feature] Allow polygon input for Concave Hull algorithm\n\nAllows polygon (and line) feature input for the Concave Hull by\nFeature algorithm.\n\nPreviously a user would have to first extract vertices from\nthe polygon to calculate the concave hull from the points, but\nthat approach ignores the interior of the polygons." "[feature] Add "Concave hull of polygons" algorithm\n\nThis algorithm calculates a concave hull for each multi-polygon\nfeature in an input layer.\n\nUnlike the standard Concave Hull algorithm, a Concave Hull of\nPolygons is a (possibly) non-convex polygon containing all the input\npolygons. The computed hull fills the gaps between the polygons\nwithout intersecting their interiors.\n\nIt is particularly useful for cases such as generalizing groups of\nbuilding outlines, creating 'district' polygons around blocks, or\nremoving gaps and joining disjoint sets of polygons.\n\nSee https://lin-ear-th-inking.blogspot.com/2022/05/concave-hulls-of-polygons.html?m=1\nfor more details"
Request for documentation
From pull request qgis/QGIS#65596
Author: @nyalldawson
QGIS version: 4.2
Expose concave hull of polygons functionality
PR Description:
This PR:
Unlike the standard Concave Hull algorithm, a Concave Hull of Polygons is a (possibly) non-convex polygon containing all the input polygons. The computed hull fills the gaps between the polygons without intersecting their interiors. It strictly follows the outer boundaries of the input polygons, allowing you to fill gaps between them without distorting their original shapes.
It is particularly useful for cases such as generalizing groups of building outlines, creating 'district' polygons around blocks, or
removing gaps and joining disjoint sets of polygons.
See https://lin-ear-th-inking.blogspot.com/2022/05/concave-hulls-of-polygons.html?m=1 for more details
Commits tagged with [need-docs] or [FEATURE]
"[feature] Allow polygon input for Concave Hull algorithm\n\nAllows polygon (and line) feature input for the Concave Hull by\nFeature algorithm.\n\nPreviously a user would have to first extract vertices from\nthe polygon to calculate the concave hull from the points, but\nthat approach ignores the interior of the polygons." "[feature] Add "Concave hull of polygons" algorithm\n\nThis algorithm calculates a concave hull for each multi-polygon\nfeature in an input layer.\n\nUnlike the standard Concave Hull algorithm, a Concave Hull of\nPolygons is a (possibly) non-convex polygon containing all the input\npolygons. The computed hull fills the gaps between the polygons\nwithout intersecting their interiors.\n\nIt is particularly useful for cases such as generalizing groups of\nbuilding outlines, creating 'district' polygons around blocks, or\nremoving gaps and joining disjoint sets of polygons.\n\nSee https://lin-ear-th-inking.blogspot.com/2022/05/concave-hulls-of-polygons.html?m=1\nfor more details"