Convex Hull
- Author: O.Conrad (c) 2011
- Menu: Shapes | Tools
Description
Implementation of 'Andrew's Monotone Chain Algorithm' for convex hull construction.
References
- Andrew, A.M. (1979): Another Efficient Algorithm for Convex Hulls in Two Dimensions. Info. Proc. Letters 9, pp.216-219.
- Sunday, D. (2001-2006): The Convex Hull of a 2D Point Set or Polygon. Geometry Algorithms Home (Web site with source code).
- The Algorithmist (9 November 2011): Monotone Chain Convex Hull. (source code).
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Points | shapes, input | SHAPES | - | - |
| Output | Convex Hull | shapes, output | HULLS | - | - |
| Minimum Bounding Box | shapes, output, optional | BOXES | - | - |
| Options | Hull Construction | choice | POLYPOINTS | This option does not apply to simple point layers. | Available Choices:
[0] one hull for all shapes
[1] one hull per shape
[2] one hull per shape part
Default: 1 |
| Polygon Convexity | boolean | POLYGONCVX | Describes a polygon's compactness as ratio of its area to its hull's area. | Default: 0 |
Command Line
Usage: saga_cmd shapes_points 12 [-SHAPES ] [-HULLS ] [-BOXES ] [-POLYPOINTS ] [-POLYGONCVX ]
-SHAPES: Points
shapes, input
-HULLS: Convex Hull
shapes, output
-BOXES: Minimum Bounding Box
shapes, output, optional
-POLYPOINTS: Hull Construction
choice
Available Choices:
[0] one hull for all shapes
[1] one hull per shape
[2] one hull per shape part
Default: 1
-POLYGONCVX: Polygon Convexity
boolean
Default: 0