Tool Name	Multi-Scale Topographic Position Index (TPI)
Tool ID	28
Library ID	ta_morphometry
Version	1.0
Author(s)	O.Conrad (c) 2016

Description

Topographic Position Index (TPI) calculation as proposed by Guisan et al. (1999).

This implementation calculates the TPI for different scales and integrates these into one single grid. The hierarchical integration is achieved by starting with the standardized TPI values of the largest scale, then adding standardized values from smaller scales where the (absolute) values from the smaller scale exceed those from the larger scale. This integration scheme has been proposed by N. Zimmermann.

Parameters

Name	Type	Identifier	Description	Constraints
Input
Elevation	grid, input	DEM
Output
Topographic Position Index	grid, output	TPI
Options
Minimum Scale	integer number	SCALE_MIN	kernel radius in cells	Minimum: 1 Default: 1
Maximum Scale	integer number	SCALE_MAX	kernel radius in cells	Minimum: 1 Default: 8
Number of Scales	integer number	SCALE_NUM		Minimum: 2 Default: 3