New feature: Band Calculator

The new module Band Calculator creates output images by performing algebraic operations (per pixel) on input images (bands) and constants. Besides standard algebraic operators (addition, multiplication, …), some bit-oriented operators, boolean operators and a conditional operator are available.
The Tool, Scenario and Time series can be found under Processing>Thematic>Band Calculator.
An expression can be specified consisting of a sequence of operators, acting on operands. The Band Calculator uses the so called Reverse Polish notation (RPN), a mathematical notation in which an operator follows its operands. The expression is visualised in a stack.
A set of input IMGs (actually bands) can be specified. Each of these will yield variables which can be used as operands in the expression. The operators in the expression act on (‘consume’) their operands, thereby producing a resulting operand. This operand can be the overall result of the expression (to be written as the output IMG), or act as input operand for a next operator.
The Tool and Scenario have different panels, specifying the input IMGs with their parameters, constant values, the expression and the output IMG destination and parameters.
In the time series/scenario, some additional parameters are available to specify the input IMGs used in the series:
– ‘normal’ periodic IMGs can be specified;
– optionally their ‘year’ can be fixed, allowing the use of LTA-like images in the expression;
– optionally their ‘period’ can be shifted with respect to the period in the time series steps. This enables “difference to previous period” alike expressions;
– non-periodic IMGs can be specified, e.g. land/sea masks.

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