Menu | Tools > Coverages > Bands > Add Computed Band |
Pop-up | coverage layer > Tools > Add Computed Band (Layers window) |
Create a new band in an existing coverage. An expression can be applied to source data to alter the values in the new band. This is useful if you need to apply a shift, but do not want to apply it to all bands in a coverage. See Filter Expressions for information on creating expressions.
A new band will be added to the input coverage, but is not displayed automatically. The Add Layer command can be used to display the layer and its data. See Layers Window for more information.
Computed bands can be removed from a coverage if they are no longer needed.
Related commands:
See also: Filter Expressions.
Interface
The Add Computed Band command uses the following dialog box.
The fields in this dialog box include:
Option | Description |
|---|---|
Name | The name to assign to the new band. |
Computed band type | Identify whether the resulting band will contain elevation values or generic numeric values (e.g., Std_Dev). |
Expression field | Define the expression to use to create new values in the new band. The expression can be entered manually or with the Expression Builder tool. 1. Click the browse button (...) to launch the Expression Builder dialog box.
This dialog box is used to create a filter expression by typing in the expression field or selecting options from the Bands list and the operator buttons. 2. Double-click the name of the band that you want to filter, or type it into the expression field. 3. Use the keyboard or the buttons in the dialog box to add the operators and values to build the filter expression. 4. Click OK when finished to return to the Add Computed Band dialog box. The Expression field is populated with the defined filter expression. |
Procedure
1. Select a raster surface in the Layers window.
2. Select the Add Computed Band command.
The Add Computed Band dialog box is displayed.
3. Type a Name for the new band.
4. Select the data type for the new band.
5. Define an expression for the new band.
6. Click OK.
The new band is added to the coverage. Depending on the expression used to create the band, the values of the data may differ from other bands in the coverage.
