Tool Focal PCA on a Grid

This tool uses the difference in cell values of a center cell and its neighbours (as specified by the kernel) as features for a Principal Component Analysis (PCA). This method has been used by Thomas and Herzfeld (2004) to parameterize the topography for a subsequent regionalization of climate variables with the principal components as predictors in a regression model.

References

Benichou, P., Lebreton, O. (1987): Prise en compte de la topographie pour la cartographie des champs pluviometriques statistiques. Meteorologie 7. Serie, no. 19.
Thomas, A., Herzfeld, U.C. (2004): REGEOTOP: New Climatic Data Fields for East Asia Based on Localized Relief Information and Geostatistical Methods. International Journal of Climatology, 24(10), 1283-1306. DOI:10.1002/joc.1058. Wiley Online Library.

Author: A.Thomas, O.Conrad (c) 2016
Menu: Spatial and Geostatistics|Grids|Principal Components

Parameters

	Name	Type	Identifier	Description	Constraints
Input	Grid	Grid (input)	`GRID`	-	-
Output	Base Topographies (*)	Grid list (optional output)	`BASE`	-	-
	Principal Components	Grid list (output)	`PCA`	-	-
	Eigen Vectors (*)	Table (optional output)	`EIGEN`	-	-
Options	Grid system	Grid system	`PARAMETERS_GRID_SYSTEM`	-	-
	Number of Components	Integer	`COMPONENTS`	number of first components in the output; set to zero to get all	Minimum: 1 Default: 7
	Output of Base Topographies	Boolean	`BASE_OUT`	-	Default: 0
	Overwrite Previous Results	Boolean	`OVERWRITE`	-	Default: 1
	Kernel Type	Choice	`KERNEL_TYPE`	-	Available Choices: [0] Square [1] Circle Default: 1
	Kernel Radius	Integer	`KERNEL_RADIUS`	Kernel radius in cells.	Minimum: 1 Default: 2
	Method	Choice	`METHOD`	-	Available Choices: [0] correlation matrix [1] variance-covariance matrix [2] sums-of-squares-and-cross-products matrix Default: 1
(*) optional

Command-line

Usage: saga_cmd statistics_grid 15 [-GRID <str>] [-BASE <str>] [-PCA <str>] [-EIGEN <str>] [-COMPONENTS <num>] [-BASE_OUT <str>] [-OVERWRITE <str>] [-KERNEL_TYPE <str>] [-KERNEL_RADIUS <num>] [-METHOD <str>]
  -GRID:<str>         	Grid
	Grid (input)
  -BASE:<str>         	Base Topographies
	Grid list (optional output)
  -PCA:<str>          	Principal Components
	Grid list (output)
  -EIGEN:<str>        	Eigen Vectors
	Table (optional output)
  -COMPONENTS:<num>   	Number of Components
	Integer
	Minimum: 1
	Default: 7
  -BASE_OUT:<str>     	Output of Base Topographies
	Boolean
	Default: 0
  -OVERWRITE:<str>    	Overwrite Previous Results
	Boolean
	Default: 1
  -KERNEL_TYPE:<str>  	Kernel Type
	Choice
	Available Choices:
	[0] Square
	[1] Circle
	Default: 1
  -KERNEL_RADIUS:<num>	Kernel Radius
	Integer
	Minimum: 1
	Default: 2
  -METHOD:<str>       	Method
	Choice
	Available Choices:
	[0] correlation matrix
	[1] variance-covariance matrix
	[2] sums-of-squares-and-cross-products matrix
	Default: 1