The Trend Surface operation is a point interpolation which requires a point map as input and returns a raster map as output. One polynomial surface is calculated by a least squares fit so that the global surface approaches all point values in the map. The calculated surface values are assigned to the output pixels. You have to specify the function with which the surface has to be calculated. For more information, refer to Trend surface : functionality.
Dialog box options:
|
Input point map: |
Select an input point map. Open the list box and select the desired input map, or drag a point map directly from the Catalog into this box. You can select a point map with a value domain, or a point map with a class or ID domain which has a linked attribute table with values (then select an attribute column with a value domain). |
|
Select one of the 8 functions to calculate a trend surface which approaches all points in your point map. |
|
|
Output raster map: |
Type a name for the output raster map. |
|
Georeference: |
Select the name of an existing georeference or create a new georeference. |
|
Value range: |
Accept the default value range, or specify your own range of possible values in the output map. |
|
Precision: |
Accept the default precision of output values, or specify your own precision. |
|
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.
See also: