SAGA-GIS Module Library Documentation (v2.1.3)

Module TOBIA


This module computes both a continuous and a categorical TOBIA (Topography Bedding Intersection Angle) Index according to Meentemeyer & Moody (2000) For computation, a slope and a aspect raster (both in radians) determining slope face orientations are required. The categorical TOBIA classifies the alignement of a geological structure to Topography into seven classes:
0) Underdip slope
1) Dip slope
2) Overdip slope
3) Steepened escarpmemt
4) Normal escarpment
5) Subdued escarpment
6) Orthoclinal slope
The continuous TOBIA index ranges from -1 to 1 (parallel orientation)
The structure TOBIA should be calculated with can be set either distributed (through dip direction and dip grids, in degrees!), or globally using integers (dip and dip direction, in degrees!). The module creates a TOBIA class integer grid, and (optionally) a continuous TOBIA index grid.

Reference: Meentemeyer R. K., Moody A. (2000). Automated mapping of conformity between topographic and geological surfaces. Computers & Geosciences, 26, 815 - 829.

Parameters

 NameTypeIdentifierDescriptionConstraints
InputSlope grid (rad)Grid (input)A--
Aspect grid (rad)Grid (input)B--
Dip grid (degrees) (*)Grid (optional input)CA grid representing the dip of the structure plane (in degrees)-
Dip direction grid (degrees) (*)Grid (optional input)DA grid representing the dip direction of the structure plane (in degrees)-
OutputTOBIA classesGrid (output)EResulting TOBIA classses (1-7) grid-
TOBIA index (*)Grid (optional output)FResulting TOBIA index (-) grid-
OptionsGlobal structure dip (degrees)Floating pointfBConstant value if no raster setDefault: 45.000000
Global structure dip direction (degrees)Floating pointfCConstant value if no raster setDefault: 90.000000
(*) optional

Command-line

Usage: saga_cmd ta_slope_stability 1 -A <str> -B <str> [-C <str>] [-D <str>] [-fB <str>] [-fC <str>] [-E <str>] [-F <str>]
  -A:<str> 	Slope grid (rad)
	Grid (input)
  -B:<str> 	Aspect grid (rad)
	Grid (input)
  -C:<str> 	Dip grid (degrees) 
	Grid (optional input)
  -D:<str> 	Dip direction grid (degrees) 
	Grid (optional input)
  -fB:<str>	Global structure dip (degrees)
	Floating point
	Default: 45.000000
  -fC:<str>	Global structure dip direction (degrees)
	Floating point
	Default: 90.000000
  -E:<str> 	TOBIA classes
	Grid (output)
  -F:<str> 	TOBIA index
	Grid (optional output)