The GeoDMS calculates with arrays. In an array each entry refers to a value for a certain position in the array. The index number defines the position of each entry, implemented in the GeoDMS by default as as zero based serial numbers (both one- and two-dimensional). The start and end position of the set of serial numbers can be different, if a range property is used for the domain unit or it is configured with a range function.

Index numbers are relevant especially in combining arrays of different domain units e.g. in relational or aggregation functions. An array with index numbers of a different domain as the domain unit of the array is called a relation or partitioning.

id function

Index numbers can be calculated with the id function. The values unit of an index number is the domain unit for which the index numbers are calculated.

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