Tool Name	TOBIA
Tool ID	1
Library ID	ta_slope_stability
Version	1.0
Author(s)	A. Günther (c) 2012

Description

This tool 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 alignment 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 tool creates a TOBIA class integer grid, and (optionally) a continuous TOBIA index grid.

References

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

Parameters

Name	Type	Identifier	Description	Constraints
Input
Slope grid (rad)	grid, input	A	A slope angle grid (in radians)
Aspect grid (rad)	grid, input	B	A aspect angle grid (in radians)
Dip grid (degrees)	grid, input, optional	C	A grid representing the dip of the structure plane (in degrees)
Dip direction grid (degrees)	grid, input, optional	D	A grid representing the dip direction of the structure plane (in degrees)
Output
TOBIA classes	grid, output	E	Resulting TOBIA classes (1-7) grid
TOBIA index	grid, output, optional	F	Resulting TOBIA index (-) grid
Options
Global structure dip (degrees)	floating point number	fB	Constant value if no raster set	Default: 45.000000
Global structure dip direction (degrees)	floating point number	fC	Constant value if no raster set	Default: 90.000000