Tool Wombling for Multiple Features (Edge Detection)

Continuous Wombling for edge detection. Uses magnitude of gradient to detect edges between adjacent cells. Edge segments connect such edges, when the difference of their gradient directions is below given threshold.

References

Fitzpatrick, M.C., Preisser, E.L., Porter, A., Elkinton, J., Waller, L.A., Carlin, B.P., Ellison, A.M. (2010): Ecological boundary detection using Bayesian areal wombling. Ecology 91(12): 3448-3455. doi:10.1890/10-0807.1.
Fortin, M.-J. and Dale, M.R.T (2005): Spatial Analysis - A Guide for Ecologists. Cambridge University Press.

Author: O.Conrad (c) 2015
Menu: Grid|Filter

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Features	Grid list (input)	`FEATURES`	-	-
Output	Edges	Grid list (output)	`EDGE_CELLS`	-	-
Output	Output (*)	Grid list (optional output)	`OUTPUT`	-	-
Options	Grid system	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Minimum Magnitude	Floating point	`TMAGNITUDE`	Minimum magnitude as percentile.	Minimum: 0.000000 Maximum: 100.000000 Default: 90.000000
	Maximum Angle	Floating point	`TDIRECTION`	Maximum angular difference as degree between adjacent segment points.	Minimum: 0.000000 Maximum: 180.000000 Default: 30.000000
	Minimum Neighbours	Integer	`TNEIGHBOUR`	Minimum number of neighbouring potential edge cells with similar direction.	Minimum: 0 Default: 1
	Alignment	Choice	`ALIGNMENT`	-	Available Choices: [0] between cells [1] on cell Default: 1
	Edge Connectivity	Choice	`NEIGHBOUR`	-	Available Choices: [0] Rooke's case [1] Queen's case Default: 1
	Additional Output	Choice	`OUTPUT_ADD`	-	Available Choices: [0] none [1] gradients [2] edge cells Default: 0
	Zero as No-Data	Boolean	`ZERO_AS_NODATA`	-	Default: 1
(*) optional

Command-line

Usage: saga_cmd grid_filter 17 [-TMAGNITUDE <double>] [-TDIRECTION <double>] [-TNEIGHBOUR <num>] [-ALIGNMENT <str>] [-NEIGHBOUR <str>] [-FEATURES <str>] [-EDGE_CELLS <str>] [-OUTPUT_ADD <str>] [-OUTPUT <str>] [-ZERO_AS_NODATA <str>]
  -TMAGNITUDE:<double> 	Minimum Magnitude
	Floating point
	Minimum: 0.000000
	Maximum: 100.000000
	Default: 90.000000
  -TDIRECTION:<double> 	Maximum Angle
	Floating point
	Minimum: 0.000000
	Maximum: 180.000000
	Default: 30.000000
  -TNEIGHBOUR:<num>    	Minimum Neighbours
	Integer
	Minimum: 0
	Default: 1
  -ALIGNMENT:<str>     	Alignment
	Choice
	Available Choices:
	[0] between cells
	[1] on cell
	Default: 1
  -NEIGHBOUR:<str>     	Edge Connectivity
	Choice
	Available Choices:
	[0] Rooke's case
	[1] Queen's case
	Default: 1
  -FEATURES:<str>      	Features
	Grid list (input)
  -EDGE_CELLS:<str>    	Edges
	Grid list (output)
  -OUTPUT_ADD:<str>    	Additional Output
	Choice
	Available Choices:
	[0] none
	[1] gradients
	[2] edge cells
	Default: 0
  -OUTPUT:<str>        	Output
	Grid list (optional output)
  -ZERO_AS_NODATA:<str>	Zero as No-Data
	Boolean
	Default: 1