Data cube

In computer programming contexts, a data cube (or datacube) is a multi-dimensional ('n-D') array of values. Typically, the term datacube is applied in contexts where these arrays are massively larger than the hosting computer's main memory; examples include multi-terabyte/petabyte data warehouses and time series of image data.Multi-dimensional arrays have long been familiar in programming languages. Fortran offers 1-D arrays and arrays of arrays, which allows the construction higher-dimensional arrays. APL supports n-D arrays with a rich set of operations. All these have in common that arrays must fit into main memory and are available only while the particular program maintaining them (such as image processing software) is running.In 2018, the ISO SQL database language is getting extended with datacube functionality as 'SQL -- Part 15: Multi-dimensional arrays (SQL/MDA)'.Many high-level computer languages treat data cubes and other large arrays as single entities distinct from their contents. These languages, of which APL, IDL, NumPy, PDL, and S-Lang are examples, allow the programmer to manipulate complete film clips and other data en masse with simple expressions derived from linear algebra and vector mathematics. Some languages (such as PDL) distinguish between a list of images and a data cube, while many (such as IDL) do not.Multi-dimensional arrays can meaningfully represent spatio-temporal sensor, image, and simulation data, but also statistics data where the semantics of dimensions is not necessarily of spatial or temporal nature. Generally, any kind of axis can be combined with any other into a datacube.