Focal PCA on a Grid
- Author: A.Thomas, O.Conrad (c) 2016
- Menu: Spatial and Geostatistics | Grids | Principal Components
Description
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.
Parameters
| Name | Type | Identifier | Description | Constraints | |
|---|---|---|---|---|---|
| Input | Grid | grid, input | GRID | - | - |
| Output | Base Topographies | grid list, output, optional | BASE | - | - |
| Principal Components | grid list, output | PCA | - | - | |
| Eigen Vectors | table, output, optional | EIGEN | - | - | |
| Options | Grid System | grid system | PARAMETERS_GRID_SYSTEM | - | - |
| Number of Components | integer number | 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 number | 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 |
Command Line
Usage: saga_cmd statistics_grid 15 [-GRID] [-BASE ] [-PCA ] [-EIGEN ] [-COMPONENTS ] [-BASE_OUT ] [-OVERWRITE ] [-KERNEL_TYPE ] [-KERNEL_RADIUS ] [-METHOD ] -GRID: Grid grid, input -BASE: Base Topographies grid list, output, optional -PCA: Principal Components grid list, output -EIGEN: Eigen Vectors table, output, optional -COMPONENTS: Number of Components integer number Minimum: 1 Default: 7 -BASE_OUT: Output of Base Topographies boolean Default: 0 -OVERWRITE: Overwrite Previous Results boolean Default: 1 -KERNEL_TYPE: Kernel Type choice Available Choices: [0] Square [1] Circle Default: 1 -KERNEL_RADIUS: Kernel Radius integer number Minimum: 1 Default: 2 -METHOD: Method choice Available Choices: [0] correlation matrix [1] variance-covariance matrix [2] sums-of-squares-and-cross-products matrix Default: 1