Tool Name	Create Grid System
Tool ID	23
Library ID	grid_tools
Version	1.0
Author(s)	Volker Wichmann (c) 2007

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
Layers	shapes list, input	SHAPESLIST
Layers	grid list, input	GRIDLIST
Output
Grid	data object Grid, output, optional	GRID
Options
Data Type	data type	DATATYPE		Available Choices: [0] bit [1] unsigned 1 byte integer [2] signed 1 byte integer [3] unsigned 2 byte integer [4] signed 2 byte integer [5] unsigned 4 byte integer [6] signed 4 byte integer [7] unsigned 8 byte integer [8] signed 8 byte integer [9] 4 byte floating point number [10] 8 byte floating point number Default: 9
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
Round Coordinates	boolean	ROUND	Rounding of extent coordinates to multiples of cellsize.	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
Buffer	floating point number	BUFFER		Default: 0.000000
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