gvSIG-Desktop 1.9 Alpha. Manual de usuario.

To perform a calculation among bands, you have to introduce an expression in the expression frame and link one band of the raster layers loaded in the TOC to one of the variables listed in the expression.

Write the expression in the expression frame. To do that, you can use all the elements of the calculator.

The decision tree contains the raster layer bands, functions, operators and constants that can be used to compose the expression. Make double click on the chosen element to introduce it in the expression (in the position where the cursor is located). For the bands, you will introduce a varaible that will be automatically associated to the band in the variables table.

Use the keyboard of the calculator to introduce numbers, operators, parenthesis and decimal separator in the expression.

In the variables table you can establish the association between the variables present in the expression and the bands of the raster layer. To link one band to one variable, or to change a link, select the table and double click over the desired band in the decision tree.

Check the box “Allow different dimensions” if you want that the bands having different dimensions, position or pixel size will be part of the calculation. This option involve the use of interpolation to obtain a result.

The result of a calculation is a one band raster layer, of type double, that contain the result of the expression for the pixels presents in ALL the input bands and the “no-data” value for the others.