Create Grid System
- Author: Volker Wichmann (c) 2007
- Menu: Grid | Grid System
Description
This tool creates a new user specified Grid System for use with other tools.
First of all, please consider the following issues before using the tool:
(a) all calculations of the tool 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 tool 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 tool 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 tool needs to create a dummy grid.
Parameters
| | Name | Type | Identifier | Description | Constraints |
|---|
| Input | Shapes Layers | shapes list, input | SHAPESLIST | - | - |
| Grids | grid list, input | GRIDLIST | - | - |
| Output | Dummy Grid | data object Grid, output, optional | GRID | - | - |
| Options | Initialization Value | floating point number | INIT | Value which is assigned to the dummy grid. | Default: 0.000000 |
| Cellsize | floating point number | CELLSIZE | - | Minimum: 0.000000
Default: 10.000000 |
| Extent Definition | choice | M_EXTENT | - | Available Choices:
[0] lower left coordinate and number of rows and columns
[1] lower left and upper right coordinates
[2] one or more shapes layers
[3] one or more grids
Default: 0 |
| Adjust | choice | ADJUST | - | Available Choices:
[0] extent to cell size
[1] cell size to left-right extent
[2] cell size to bottom-top extent
Default: 0 |
| Left | floating point number | XMIN | - | Default: 0.000000 |
| Right | floating point number | XMAX | - | Default: 100.000000 |
| Columns | integer number | NX | - | Minimum: 1
Default: 10 |
| Bottom | floating point number | YMIN | - | Default: 0.000000 |
| Top | floating point number | YMAX | - | Default: 100.000000 |
| Rows | integer number | NY | - | Minimum: 1
Default: 10 |
| Use Offset | boolean | USEOFF | - | Default: 0 |
| X Offset | floating point number | XOFFSET | Positive values result in a shift in E direction. | Default: 0.000000 |
| Y Offset | floating point number | YOFFSET | Positive values result in a shift in N direction. | Default: 0.000000 |
Command Line
Usage: saga_cmd grid_tools 23 [-GRID ] [-INIT ] [-CELLSIZE ] [-M_EXTENT ] [-ADJUST ] [-XMIN ] [-XMAX ] [-NX ] [-YMIN ] [-YMAX ] [-NY ] [-SHAPESLIST ] [-GRIDLIST ] [-USEOFF ] [-XOFFSET ] [-YOFFSET ]
-GRID: Dummy Grid
data object Grid, output, optional
-INIT: Initialization Value
floating point number
Default: 0.000000
-CELLSIZE: Cellsize
floating point number
Minimum: 0.000000
Default: 10.000000
-M_EXTENT: Extent Definition
choice
Available Choices:
[0] lower left coordinate and number of rows and columns
[1] lower left and upper right coordinates
[2] one or more shapes layers
[3] one or more grids
Default: 0
-ADJUST: Adjust
choice
Available Choices:
[0] extent to cell size
[1] cell size to left-right extent
[2] cell size to bottom-top extent
Default: 0
-XMIN: Left
floating point number
Default: 0.000000
-XMAX: Right
floating point number
Default: 100.000000
-NX: Columns
integer number
Minimum: 1
Default: 10
-YMIN: Bottom
floating point number
Default: 0.000000
-YMAX: Top
floating point number
Default: 100.000000
-NY: Rows
integer number
Minimum: 1
Default: 10
-SHAPESLIST: Shapes Layers
shapes list, input
-GRIDLIST: Grids
grid list, input
-USEOFF: Use Offset
boolean
Default: 0
-XOFFSET: X Offset
floating point number
Default: 0.000000
-YOFFSET: Y Offset
floating point number
Default: 0.000000