Module Convex Hull
Implementation of 'Andrew's Monotone Chain Algorithm' for convex hull construction. 
References:
Algorithmist (2011): Monotone Chain Convex Hull. algorithmist.com.
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. Softsurfer.com.
- Author: O.Conrad (c) 2011
 
- Specification: $Specification
 
- Menu: Shapes|Tools
 
Parameters
|   | Name | Type | Identifier | Description | Constraints | 
| Input | Points | Shapes (input) | SHAPES | - | - | 
| Output | Convex Hull | Shapes (output) | HULLS | - | - | 
 | Minimum Bounding Box (*) | Shapes (optional output) | 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 | 
| (*) optional | 
Command-line
Usage: saga_cmd shapes_points 12 -SHAPES <str> [-HULLS <str>] [-BOXES <str>] [-POLYPOINTS <str>]
  -SHAPES:<str>    	Points
	Shapes (input)
  -HULLS:<str>     	Convex Hull
	Shapes (output)
  -BOXES:<str>     	Minimum Bounding Box
	Shapes (optional output)
  -POLYPOINTS:<str>	Hull Construction
	Choice
	Available Choices:
	[0] one hull for all shapes
	[1] one hull per shape
	[2] one hull per shape part
	Default: 1