About

Goal of this site is to showcase standards-based services on Big Earth Data, in particular: spatio-temporal coverages. The service is implemented using the rasdaman Big Array Analytics engine. The maintainers hope to contribute to proliferation and uptake of OGC's and ISO's coverage services.

Spatio-Temporal Coverages

Coverage data are digital representations of space/time varying phenomena, modelled as spatio-temporal regular and irregular grids, timeseries, point clouds, and general meshes. They unify representation and handling of 1-D sensor time series, 2-D satellite imagery, 3-D x/y/t image time series and x/y/z geoscientific models, 4-D x/y/z/t climate and ocean data sets, but also non-gridded data like point clouds, TINs, and other meshes.

Through Web Services, coverages can be accessed conveniently through the Web Coverage Service (WCS) suite and the Web Coverage Processing Service (WCPS) coverage query language.

Who Defines Coverages?

An abstract definition of coverages is provided by ISO 19123 (which is identical to OGC Abstract Topic 6). This definition is abstract and allows for diverging, non-interoperable implementations (which, in fact exist - a clear indicator is that they come with their own specific clients). Therefore, OGC has complemented this abstract specification with a concrete, interoperable definition of coverages given by OGC Coverage Implementation Schema (CIS) available from the OGC standards page. (in Spring 2015 renamed from OGC GML 3.2.1 Application Schema - Coverages (GMLCOV) which misleadingly suggested a pure GML encoding while the coverage model actually is independent from encodings and can be mapped to any suitable format, like GeoTIFF, JPEG2000, and NetCDF.

ISO is in the process of adopting CIS as its concrete coverage model with the goal of establishing

Coverage Services

While (tentatively) many standards allow to serve out coverages, the OGC WCS suite provides the most versatile and functionality rich service portfolio. For example, a WFS can only deliver a complete coverage whereas WCS and WCPS allow subsetting, format encoding, and processing.

The modular WCS suite consists of a Core (mandatory for all implementations) which only defines subsetting (i.e., trimming and slicing) oc verages as well as their format encoding. Extensions (optional to implement) add further functionality facets in a compatible, coherent manner.

The OGC OGC Web Coverage Processing Service (WCPS) Language standard defines OGC's coverage analytics language. WCPS unleashes open, flexible Web access to sensor and observation data archives for navigation, extraction, aggregation, and analysis.

More Resources

A primer on coverage data and services is provided on this site: WMS, WCS, WCPS (with manual and tutorial), and WPS. Further resources include:

See Them in Action

...and proceed to the demonstration area!