====== Raster Algebra ======

The Raster Algebra Utility allows you to calculate new rasters by combining a number of source bands.   
These bands are combined using a user-specified formula.

{{rap_calculator.png|:extensions:rasterprocessing:rap_calculator.png}}


===== ORA Files =====

Expressions can be saved as ORA (Orbit Raster Algebra) files.

These files contain the following information : 
  * The location of the datasets involed in the formula
  * The location of the last output file
  * The formula itself

When you open an ORA file, the datasets involved will be automatically opened in Orbit GIS.

===== Set-up a Project =====

To setup a project, you must first open some image datasets in Orbit GIS.
Those (and only those) datasets will be made selectable in the image calculator.

==== Writing a formula ====

==== Processing the formula ====

==== Save Project ====