# TPI Based Landform Classification

O.Conrad (c) 2011
Topographic Position Index (TPI) calculation as proposed by Guisan et al. (1999). This is literally the same as the difference to the mean calculation (residual analysis) proposed by Wilson & Gallant (2000).
References:
- Guisan, A., Weiss, S.B., Weiss, A.D. (1999): GLM versus CCA spatial modeling of plant species distribution. Plant Ecology 143: 107-122.
- Weiss, A.D. (2000): Topographic Position and Landforms Analysis. poster.
- Wilson, J.P. & Gallant, J.C. (2000): Terrain Analysis - Principles and Applications.

## Parameters

Grid system
Grid system
  Grid system
Elevation
Input Grid
Landforms
Output Grid
Radius
Value range
  radius in map units
  Minimum: 1.63344663707e-316; Maximum: 1.63339209222e-316
Radius
Value range
  radius in map units
  Minimum: 1.63359050898e-316; Maximum: 1.63353596414e-316
Weighting
Parameters
  bandwidth has to be given as percentage of the (outer) radius