rasdaman newsletter 01/2016
OGC Requests Comments on Coverage Implementation Schema
December 2015. The Open Geospatial Consortium (OGC) requests comments on the OGC Coverage Implementation Schema (abbreviated as "CIS"). This candidate OGC Standard complements the OGC Abstract Topic 6 Standard (which is identical to ISO 19123) with a concrete coverage model whose implementations are conformance testable and, hence, are interoperable. ISO has expressed interest to adopt CIS 1.1 as ISO 19123-2.
The Coverage Implementation Schema version 1.1 is the backwards compatible successor of the "GML 3.2.1 Application Schema - Coverages" version 1.0 (abbreviated as "GMLCOV"). The CIS candidate standard has been renamed to reflect the breadth of available data encodings beyond GML and to reduce market confusion. While incorporating all features of GMLCOV 1.0, CIS 1.1 adds important new modeling capabilities, such as coverage partitioning, interpolation, geometry/value pairs, SensorML support, and point clouds. Further, a general model for all combinations of non-regular grids is supported, which includes GML 3.3 coverage types as special cases.
The OGC Abstract Topic 6 Standard defines an abstract coverage model. Coverages represent homogeneous collections of values located in space/time, such as spatio-temporal sensor, image, simulation, and statistics data. Common examples include 1-D timeseries, 2-D imagery, 3-D image time series or spatial models, as well as 4-D climate and ocean data. Generally, coverages encompass multi-dimensional regular and irregular grids, point clouds, and meshes.
The OGC Coverage Implementation Schema complements OGC Abstract Topic 6 with a concrete coverage structure definition of a subset of coverage models in OGC Abstract Topic 6 that can be conformance tested, regardless of the implementations’ data format encoding. CIS enables a wide range of interoperable implementations.
Coverages can be encoded in suitable formats (such as GML, JSON, GeoTIFF or CF-netCDF) and can be partitioned, e.g., for a time-interleaved representation. Coverages are independent of service definitions and therefore can be accessed through a variety of OGC services types, such as the Web Coverage Service (WCS) Standard. The coverage structure can serve a wide range of coverage application domains, thereby contributing to harmonization and interoperability between and across these domains.