The ID Grid map operation uses a coordinate system and optionally an attribute table as input and creates a polygon map as output. The output polygon map consists of rectangular grid cells with a unique ID, and can be linked to a table with attribute data when sample data is available for the rectangular grid cells (e.g. biodiversity data in 5x5 km blocks).
Besides the above, the operation can create an additional point map with label points at the center of each grid cell.
Dialog box options:
Coordinate System: |
Select an existing coordinate system or create a new coordinate system by using the create button. Open the list box and select the desired coordinate system, or drag a coordinate system directly from the Catalog into this box. |
Origin Coordinate: |
The origin coordinate is the lower left corner of the output grid map. Depending on the coordinate system, coordinates have to be typed as (X, Y) coordinates or as (Lat, Lon) coordinates. In case you selected a metric coordinate system: specify the X and Y coordinates of the origin coordinate. In case you selected a LatLon coordinate system: specify the Lat and Lon coordinates of the origin coordinate as degrees, minutes, seconds, N/S, E/W. |
Grid Size (Width, Height): |
Select this check box to define the grid size (width, height). The grid size should always be specified in the units of the coordinate system (meters or degrees). Grid cell width and grid cell height are usually the same but they could be different. When you clear this check box you need to specify the number of vertical and horizontal grids and the opposite corner coordinate. |
Nr. of vert, horz Grids: |
Select this check box to define the number of vertical and horizontal grid cells. The number of grids will be used together with the grid size to calculate the size of the ID grid map. When you clear this check box you need to specify the grid size and the opposite corner coordinate. |
Opposite Coordinate: |
The opposite corner coordinate is the corner opposite to the corner specified as 'origin coordinate'. The opposite corner coordinate text boxes are only visible when either the Grid Size check box or the Nr. of vert, horz Grids check box is cleared. Depending on the input coordinate system, coordinates have to be typed as (X, Y) coordinates or as (Lat, Lon) coordinates. In case you selected a metric coordinate system: specify the X and Y coordinates of the opposite coordinate. In case you selected a LatLon coordinate system: specify the Lat and Lon coordinates of the opposite coordinate as degrees, minutes, seconds, N/S, E/W. |
Direction Point: |
Optional. Select this check box to define a direction point. The direction point is a point on the positive Y-axis from the lower left corner (origin) of the ID grid map and is used to rotate the grids. Depending on the input coordinate system, coordinates have to be typed as (X, Y) coordinates or as (Lat, Lon) coordinates. In case you selected a metric coordinate system: specify the X and Y coordinates of the direction point. In case you selected a LatLon coordinate system: specify the Lat and Lon coordinates of the direction point as degrees, minutes, seconds, N/S, E/W. Clear this check box when you want to create a north-oriented ID grid map. |
Order: |
Select the direction which should be used to label the grid cells. Available directions are: Horizontal, Horizontal Continued, Vertical and Vertical Continued. By default ordering is Horizontal. For more information about the different types of ordering, see ID Grid map : algorithm. |
Start Corner: |
Select a corner which should be used to start labeling the grid cells. Available options are: Lower Left, Lower Right, Upper Left and Upper Right. By default the Lower Left corner is the starting corner. |
Start Nr: |
Type an integer (>= 0) that will be used as an initial number to start labeling the grid cells. The default value is 1. |
Steps: |
Type an integer (>= 0) for the step size. The step size (default value 1) is a number that is used to determine the increase/decrease of individual grid cell numbers during the labeling process. For instance when the step size is 10 and the starting number is 1 then the IDs in a output polygon map will appear as 1, 11, 21, 31, 41 etc. |
Prefix: |
Optionally, type some characters that should be used as a prefix for the IDs in the output map. |
Postfix: |
Optionally, type some characters that should be used as a suffix for the IDs in the output map. |
Table: |
Optional. Select this check box when you have an existing attribute table with an ID domain that you
wish to link to the output polygon
map. The ID to be assigned to each grid cell should be available in the ID domain of the attribute table otherwise undefined values will be assigned to the
grid cells during the labeling process. See ID Grid map : algorithm for more information. |
Output Label Points: |
Optional. Select this check box when you wish to obtain an additional point map with label points at the center for each individual grid
cell. The name of the point map will be the same as the name specified for the output polygon map. |
Output Polygon Map: |
Type a name for the output polygon map that will contain the ID grid cells. |
Description: |
Optionally, type a description for the output map. The description will appear in the status bar of the Main window when moving the mouse pointer over the map in a Catalog, and in the title bar of a map window when the output map is displayed. If no description is supplied, the output map will use its own definition as description. |
When you click the Show button, the dependent output map will be defined, calculated and shown. When you click the Define button, the dependent output map will only be defined; if necessary the map will be calculated later, for instance when the map is opened to be displayed.
Notes:
See also: