FAIRiCUBE Rasdaman Datacubes#

rasdaman is a vertically-integrated solution for managing and providing access via standardized API to spatio-temporal datacubes of any size and dimensions. Out of the box it provides support for the latest OGC datacube standards, including WCS 2.1, WCPS 1.0, WMS 1.3, and WMTS 1.0, as well as experimental support for OGC OAPI-Coverages and openEO.

Through these API, datacubes can be filtered, subsetted along any axes, processed and analyzed, and finally results can be exported in a variety of 2D formats (GeoTIFF, PNG, JPEG, etc) as well as more general nD formats such as netCDF and JSON.

Full documentation of all capabilities of rasdaman can be found on the dedicated rasdaman documentation. This section documents a subset of the features most relevant for FAIRiCUBE partners and users.

The rasdaman FAIRiCUBE webpage aggregates the most important ways to access the rasdaman service, thereby serving as an entry point for users. There are several clients available out of the box in the browser.

Web Coverage Service (WCS)#

The OGC Web Coverage Service (WCS) standard defines support for modeling and retrieval of geospatial data as coverages (e.g. sensor, image, or statistics data). This section provides a very high-level overview; check the rasdaman documentation for further details.

WCS consists of a Core specification for basic operation support with regards to coverage discovery and retreival with three fundamental operations:

  • GetCapabilities - returns overal service information and a list of available coverages

  • DescribeCoverage - detailed description of a specific coverage

  • GetCoverage - retreive a whole coverage, or arbitrarily restricted on any of its axes whether by new lower/upper bounds (trimming) or at a single index (slicing)

Various extension specifications define optional capabilities that a service could provide on offered coverage objects: data import, selecting and combining coverage bands, scaling (resampling) data, reprojecting to a different CRS, processing and analytics, etc. Processing and analytics is the topic of the next section.

Web Coverage Processing Service (WCPS)#

The WCS Processing extension enables advanced analytics on coverages through Web Coverage Processing Service (WCPS) queries. For example, to calculate the average on a subset of a coverage named AvgLandTemp:

https://ows.rasdaman.org/rasdaman/ows?service=WCS&version=2.0.1&request=ProcessCoverages&query=for $c in (AvgLandTemp) return avg($c[Lon(-90.0:85.3), ansi("2014-10-01")])

Note that the query part (following the &query= parameter in the URL) needs to be URL-encoded because it may contain characters that are not allowed in URLs. This can be done online, e.g. with this URLEncoder, or one can use a tool such as curl that does it automatically:

curl 'https://ows.rasdaman.org/rasdaman/ows?service=WCS&version=2.0.1&request=ProcessCoverages' \
     -d 'query=for $c in (AvgLandTemp) return avg($c[Lon(-90.0:85.3), ansi("2014-10-01")])'

Check the rasdaman documentation for an overview of WCPS queries.

Web Map Service (WMS)#

The OGC Web Map Service (WMS) standard defines map portrayal on geo-spatial data. In rasdaman, a WMS service can be enabled on any coverage, including 3-D or higher dimensional; the latest 1.3.0 version is supported.

rasdaman supports two operations: GetCapabilities, GetMap from the standard. We will not go into the details as users do not normally hand-write WMS requests, but let a client tool or library generate them instead.

Datacubes Dashboard#

The rasdaman dashboard provides a custom tailored user interface through which one can search the available datacubes, run various prepared or freely written WCPS queries and visualize datacubes on a globe (see Figures below).

rasdaman-dashboard visualize coverage
The Corine Land Cover datacube visualized on the globe, with datacube description and a legend.
rasdaman-dashboard execute WCPS query
This figure shows executing a WCPS query in the WCPS query editor and showing the result.

The dashboard provides anonymous access, which allows to see the available datacubes and see information about them. To visualize, execute queries and download data it is necessary to login. Users can login either with a valid username and password, or through their GitHub account if it's been authorized by the administrator of the rasdaman service.

rasdaman-dashboard login page
Dashboard login page.

OGC Web Services Client#

The rasdaman WSClient is designed more closely to cover the features of the supported OGC Web Services: WCS for datacube download and processing with WCPS queries via the Processing extension, as well as WMS/WMTS for datacube visualization.

For more details on the features and interface check the official documentation.

rasdaman ows client
rasdaman ows client.

Python WCS and WCPS Clients#

The following two Python libraries make it easy to access and query datacubes in rasdaman for Python developers:

  • WCS python library (GitHub repo, documentation) allows to extract information about datacubes: available datacubes, their bounding box/axes, range type, metadata, etc.
  • WCPS python library (GitHub repo, documentation) allows to dynamically build WCPS queries and execute on a WCPS server.

Further Clients#

As datacube access is provided via standardized API, there's many different clients that can access the data in rasdaman. The rasdaman documentation lists many of these, often with guidelines on how to get started with each.