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 Principle Components 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 principle components as predictors in a regression model.
- Author: A.Thomas, O.Conrad (c) 2016
- Menu: Spatial and Geostatistics|Grids|Principle Components
Parameters
| Name | Type | Identifier | Description | Constraints |
Input | Grid | Grid (input) | GRID | - | - |
Output | Principal Components | Grid list (output) | PCA | - | - |
Eigen Vectors (*) | Table (optional output) | EIGEN | - | - |
Options | Grid system | Grid system | PARAMETERS_GRID_SYSTEM | - | - |
Grid system | Grid system | PCA_GRIDSYSTEM | - | - |
Number of Components | Integer | COMPONENTS | number of first components in the output; set to zero to get all | Minimum: 1 Default: 7 |
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>] [-PCA <str>] [-EIGEN <str>] [-COMPONENTS <num>] [-OVERWRITE <str>] [-KERNEL_TYPE <str>] [-KERNEL_RADIUS <num>] [-METHOD <str>]
-GRID:<str> Grid
Grid (input)
-PCA:<str> Principal Components
Grid list (output)
-EIGEN:<str> Eigen Vectors
Table (optional output)
-COMPONENTS:<num> Number of Components
Integer
Minimum: 1
Default: 7
-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