TENTATIVE IDIS DATA-MODEL Clause Samples

TENTATIVE IDIS DATA-MODEL. The scope of this data-model is to try to avoid or at least limit extensions. In previous data models, the required coordinates (used for data ordering and search) make them incompatible and difficult (or even impossible) to extend. For the IVOA, the astronomy heritage implied that the required coordinates are the sky coordinates (Right Ascension and Declination). In the case of planetary and space physics (e.g., PDAP or SPASE), the required coordinate is the time range (Start_Time, Stop_Time). These two requirements are inconsistent and may be incompatible: the sky coordinates have no sense in most of planetary and space sciences, whereas the time range (at year to sub-second scales) is not a primary coordinate in case of astronomical data. Even more, these two models may not be adequate either for modeled or time integrated data such as maps of planetary surfaces, where the adequate coordinate is that of the planet. Laboratory measurements (such as spectroscopy of planetary equivalent materials or ice propagation properties) do not fit either into these two implemented data models. We thus do not propose a specific required coordinate type. The data model is hierarchically decomposed as follows: - a DataSet contains a series of Granules. - a Granule (usually a file) contains a series of Parameters (measured or instrumental). - a Parameter (usually the data) is a series of physical or instrumental quantities items/values.