Tool Name	Wombling (Edge Detection)
Tool ID	16
Library ID	grid_filter
Version	1.0
Author(s)	O.Conrad (c) 2015

Description

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.

Parameters

Name	Type	Identifier	Description	Constraints
Input
Feature	grid, input	FEATURE
Output
Edge Points	shapes, output, optional	EDGE_POINTS
Edge Segments	shapes, output, optional	EDGE_LINES
Gradients	grid list, output, optional	GRADIENTS
Options
Minimum Magnitude	floating point number	TMAGNITUDE	Minimum magnitude as percentile.	Minimum: 0.000000 Maximum: 100.000000 Default: 90.000000
Maximum Angle	floating point number	TDIRECTION	Maximum angular difference as degree between adjacent segment points.	Minimum: 0.000000 Maximum: 180.000000 Default: 30.000000
Minimum Neighbours	integer number	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
Output of Gradients	boolean	GRADIENTS_OUT		Default: 0