Module Create Grid System
This module creates a new user specified Grid System for use with other modules.
First of all, please consider the following issues before using the module:
(a) all calculations of the module refer to the lower left corner of the grid system, i.e. the xMin and yMin values. This coordinate is fixed unless you specify an offset.
(b) the module follows the philosophy of SAGA in that the values describing the extent refer to the cell centers. If you like to match the extent with the border of a grid, use an offset.
The module provides four possibilities to set/determine the extent of the grid system:
(1) by specifying the coordinate of the lower left cell (xMin, yMin) and the number of cells in W-E (NX) and S-N (NY) direction
(2) by specifying the coordinates the of lower left (xMin, yMin) and the upper right (xMax, yMax) cell
(3) by the extent of the shape(s) provided in the Data Objects section
(4) by the extent of the grid(s) provided in the Data Objects section
After selecting the appropriate method to determine the extent, the next step is to specify the cellsize of the new grid system.
For all methods supplied to determine the extent but number (1), three possibilities are provided to adjust cellsize and grid system extent (please remember, the lower left corner is fixed!):
(I) adjust the extent to match the cellsize
(II) adjust the cellsize to match the extent in E-W direction
(III) adjust the cellsize to match the extent in S-N direction
Finally it is possible to apply an offset to the lower left corner of the grid system. In this case check the Use Offset option and specify the offset in W-E and S-N direction. Positive values result in a shift in E/N, negative in W/S direction.
In order to create the grid system the module needs to create a dummy grid.
- Author: Copyrights (c) 2007 by Volker Wichmann
- Specification: grid
- Menu: Grid|Grid System
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Shape(s) (*) | Shapes list (optional input) | SHAPESLIST | Shape(s) to fit extent to | - |
| Grid(s) (*) | Grid list (optional input) | GRIDLIST | Grid(s) to fit extent to | - |
| Output | Dummy Grid (*) | Data Object (optional output) | GRID | - | - |
| Options | Set extent by | Choice | M_EXTENT | Please choose a method of module operation. | Available Choices:
[0] xMin, yMin, NX, NY
[1] xMin, yMin, xMax, yMax
[2] Shape(s)
[3] Grid(s)
Default: 0 |
| xMin | Floating point | XMIN | minimum x value | Default: 0.000000 |
| yMin | Floating point | YMIN | minimum y value | Default: 0.000000 |
| xMax | Floating point | XMAX | maximum x value | Default: 100.000000 |
| yMax | Floating point | YMAX | maximum y value | Default: 100.000000 |
| NX | Integer | NX | number of cells in W-E direction | Minimum: 1
Default: 10 |
| NY | Integer | NY | number of cells in S-N direction | Minimum: 1
Default: 10 |
| Cellsize | Floating point | CELLSIZE | Cellsize | Minimum: 0.000000
Default: 10.000000 |
| Adjust | Choice | ADJUST | Choose method how to adjust input values. | Available Choices:
[0] Extent to CellSize
[1] CellSize to W-E Extent
[2] CellSize to S-N Extent
Default: 0 |
| Use Offset | Boolean | USEOFF | Apply offset? | Default: 0 |
| X offset | Floating point | XOFFSET | Positive values result in a shift in E direction. | Default: 0.000000 |
| Y offset | Floating point | YOFFSET | Positive values result in a shift in N direction. | Default: 0.000000 |
| Initialization Value | Floating point | INIT | Value which is assigned to the dummy grid. | Default: 1.000000 |
| (*) optional |
Command-line
Usage: saga_cmd grid_tools 23 [-GRID <str>] [-M_EXTENT <str>] [-XMIN <str>] [-YMIN <str>] [-XMAX <str>] [-YMAX <str>] [-NX <num>] [-NY <num>] [-CELLSIZE <str>] [-ADJUST <str>] [-USEOFF <str>] [-XOFFSET <str>] [-YOFFSET <str>] [-INIT <str>] [-SHAPESLIST <str>] [-GRIDLIST <str>]
-GRID:<str> Dummy Grid
Data Object (optional output)
-M_EXTENT:<str> Set extent by
Choice
Available Choices:
[0] xMin, yMin, NX, NY
[1] xMin, yMin, xMax, yMax
[2] Shape(s)
[3] Grid(s)
Default: 0
-XMIN:<str> xMin
Floating point
Default: 0.000000
-YMIN:<str> yMin
Floating point
Default: 0.000000
-XMAX:<str> xMax
Floating point
Default: 100.000000
-YMAX:<str> yMax
Floating point
Default: 100.000000
-NX:<num> NX
Integer
Minimum: 1
Default: 10
-NY:<num> NY
Integer
Minimum: 1
Default: 10
-CELLSIZE:<str> Cellsize
Floating point
Minimum: 0.000000
Default: 10.000000
-ADJUST:<str> Adjust
Choice
Available Choices:
[0] Extent to CellSize
[1] CellSize to W-E Extent
[2] CellSize to S-N Extent
Default: 0
-USEOFF:<str> Use Offset
Boolean
Default: 0
-XOFFSET:<str> X offset
Floating point
Default: 0.000000
-YOFFSET:<str> Y offset
Floating point
Default: 0.000000
-INIT:<str> Initialization Value
Floating point
Default: 1.000000
-SHAPESLIST:<str> Shape(s)
Shapes list (optional input)
-GRIDLIST:<str> Grid(s)
Grid list (optional input)