Module Valley and Ridge Detection (Top Hat Approach)

Calculating fuzzy valley and ridge class memberships using the Top Hat approach. Based on the AML script 'tophat' by Jochen Schmidt, Landcare Research.

References:
Rodriguez, F., Maire, E., Courjault-Rad'e, P., Darrozes, J. (2002): The Black Top Hat function applied to a DEM: a tool to estimate recent incision in a mountainous watershed. (Estib`ere Watershed, Central Pyrenees). Geophysical Research Letters, 29(6), 9-1 - 9-4.

Author: O.Conrad (c) 2013
Specification: grid
Menu: Terrain Analysis|Terrain Classification

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Elevation	Grid (input)	`DEM`	-	-
Output	Valley Depth (*)	Grid (optional output)	`VALLEY`	-	-
	Hill Height (*)	Grid (optional output)	`HILL`	-	-
	Valley Index	Grid (output)	`VALLEY_IDX`	-	-
	Hill Index	Grid (output)	`HILL_IDX`	-	-
	Hillslope Index (*)	Grid (optional output)	`SLOPE_IDX`	-	-
Options	Valley Radius	Floating point	`RADIUS_VALLEY`	radius given in map units used to fill valleys	Minimum: 0.000000 Default: 1000.000000
	Hill Radius	Floating point	`RADIUS_HILL`	radius given in map units used to cut hills	Minimum: 0.000000 Default: 1000.000000
	Elevation Threshold	Floating point	`THRESHOLD`	elevation threshold used to identify hills/valleys	Minimum: 0.000000 Default: 100.000000
	Slope Index	Choice	`METHOD`	-	Available Choices: [0] default [1] alternative Default: 0
(*) optional

Command-line

Usage: saga_cmd ta_morphometry 24 [-DEM <str>] [-VALLEY <str>] [-HILL <str>] [-VALLEY_IDX <str>] [-HILL_IDX <str>] [-SLOPE_IDX <str>] [-RADIUS_VALLEY <str>] [-RADIUS_HILL <str>] [-THRESHOLD <str>] [-METHOD <str>]
  -DEM:<str>          	Elevation
	Grid (input)
  -VALLEY:<str>       	Valley Depth
	Grid (optional output)
  -HILL:<str>         	Hill Height
	Grid (optional output)
  -VALLEY_IDX:<str>   	Valley Index
	Grid (output)
  -HILL_IDX:<str>     	Hill Index
	Grid (output)
  -SLOPE_IDX:<str>    	Hillslope Index
	Grid (optional output)
  -RADIUS_VALLEY:<str>	Valley Radius
	Floating point
	Minimum: 0.000000
	Default: 1000.000000
  -RADIUS_HILL:<str>  	Hill Radius
	Floating point
	Minimum: 0.000000
	Default: 1000.000000
  -THRESHOLD:<str>    	Elevation Threshold
	Floating point
	Minimum: 0.000000
	Default: 100.000000
  -METHOD:<str>       	Slope Index
	Choice
	Available Choices:
	[0] default
	[1] alternative
	Default: 0