The range of a coverage is the set of valid output values. In Apache SIS, the distinction between ranges of numerical values and range of any types of values is represented by Number­Range and Range classes respectively. The Number­Range is used more often, and is also the one that most closely approaches the the common mathematical concept of an interval. This textual representation approaches the specifications of ISO 31-11 standard, except that the comma is replaced by the character “…” as the separator of minimal and maximal values. For example, “[0 … 256)” represents the range of values from 0 inclusive to 256 exclusive.

Range objects are only indirectly associated with coverages. In SIS, the values that can return coverages are described by objects of the Sample­Dimension type. It is these that contain instances of Range, as well as other information such as transfer function (described later).

The SampleDimension.Builder provides convenience methods for building the sample dimensions of a coverage. The usage pattern is to invoke the following methods:

• setName(…) for giving a name to a band.
• addQuantitative(…) for declaring a range of sample values to convert to units of measurement.
• addQualitative(…) for declaring "no data" values.
• setBackground(…) for declaring a "no data" value which can also be used for filling empty space.