Table of Contents:

Coverages & Datacubes:
the Big Picture

This page gives an overview of the coverage data and service model, in particular the WCS service suite. Datacubes form a special type of coverages which continues to receive particular attention.



Figure: Coverage data and service model overview

Coverage specifications (with adoption status)

All coverage-related adopted standards - in particular: the CIS and WCS suites - can be found on the OGC WCS page, except for the WCPS language definition which is maintained separately for historical reasons.

Standards are grouped along the common IT abstraction hierarchy:
  • conceptual level: terminology and concepts
  • logical level: interoperable data and service specifications
  • physical level: specific encodings

Abstract Models (conceptual level)

Standards on this level of abstraction define terminology and concepts of coverage data and services.

Note: In the past, this distinction has not been made this clearly in the standards. Often concepts were directly expressed in GML (more recently, in JSON) rather than separating them cleanly. In recent years, more attention has been paid to that at least in the WCS suite so the more recent standards split into separate documents (ex: ISO 19123-1 and 19123-2) or at least have separate conformance classes (ex: WCS service functionality vs request/response encoding).

Concrete Coverage Model (logical level)

Coverage Data Model

    • Coverage Implementation Schema (CIS), version 1.1 document and schemas for XML, JSON, RDF and examples: (adopted, backwards compatible next version of CIS/GMLCOV 1.0); key features (see rationales):
      • CIS 1.1 is backwards compatible to CIS/GMLCOV 1.0, and so does not require any change to WCS 2.0 (just a formal extension to allow WCS instances serve the new coverage types - accomplished by WCS 2.1).
      • CIS 1.1 adds class GeneralGridCoverage which is simplified and more powerful than the legacy CIS 1.0 grid distinction of Rectified / Referenceable Grid. Instead, grids are described through various axis types: non-referenced, regular, irregular, etc; these axis types can be combined arbitrarily in a coverage (eg, regular, rectified Lat and Long axes together with an irregular time axis).
      • support for grids as per SensorML 2.0
      • coverages can be partitioned into sub-coverages while still acting as one (eg, in a WCS GetCoverage request)
      • support for XML, JSON, and RDF
  • Coverage Implementation Schema - ReferenceableGridCoverage Extension, OGC 16-083r2: adopted extension to CIS 1.0
    • This standard closes a gap of GML 3.2.1 inherited by CIS 1.0 which has left ReferenceableGridCoverage underspecified. While CIS 1.1 GeneralGridCoverage encompasses the concept of ReferenceableGridCoverages some stakeholders requested to specifically provide this coverage type. Therefore, this standard has been crafted as an extension to CIS 1.0.
  • Coverage Implementation Schema (CIS), version 1.0.1 document and schema, OGC 09-146r2: adopted
    • renamed GML 3.2.1 Application Schema - Coverages (GMLCOV) to Coverage Implementation Schema (CIS) resulting from a renaming of OGC to better reflect contents of the standard (too many people believed GMLCOV is just a GML encoding, while it actually defines interoperable coverage structures in a format-independent way)

Coverage Service Model

Coverage Data and Request Encodings (physical level)

Coverage Format Encodings

Coverage Service Protocol Bindings

Non-Coverage documents:

Technical Coverage resources

I Attachment Action Size Date Who Comment
08-068r3_Web-Coverage-Processing-Service-Language_2020-08-11.pdfpdf 08-068r3_Web-Coverage-Processing-Service-Language_2020-08-11.pdf manage 1 MB 09 Nov 2020 - 13:15 PeterBaumann WCPS 1.1
09-045r1_WPS_Application-Profile_-_Coverages_2014-11-04.zipzip manage 62 K 02 Jan 2015 - 14:24 PeterBaumann 09-045r1 WPS Application Profile - Coverages
09-146r3_Coverage-Implementation-Schema_2016-04-14.zipzip manage 731 K 14 Apr 2016 - 16:04 PeterBaumann Coverage Implementation Schema 1.1 (draft, incorporating RFC comments)
13-057_WCS_Extension_-_Transaction_2014-09-15.zipzip manage 146 K 09 Dec 2015 - 14:50 PeterBaumann 13-057 WCS Extension - Transaction
14-121_WCS_Extension_-_XPath_2014-12-01.docxdocx 14-121_WCS_Extension_-_XPath_2014-12-01.docx manage 96 K 17 Dec 2015 - 15:33 PeterBaumann 14-121 WCS Extension - XPath (draft)
14-121_Web-Information-Service_2016-05-18.zipzip manage 94 K 03 Jun 2016 - 21:14 PeterBaumann OGC Web Information Service (WIS) 1.0
15-065r1_Testbed_11_Referenceable_Grid_Harmonization_Engineering_Report_FINAL.pdfpdf 15-065r1_Testbed_11_Referenceable_Grid_Harmonization_Engineering_Report_FINAL.pdf manage 1 MB 03 Oct 2017 - 14:29 PeterBaumann Testbed-11 Engineering Report motivating CIS 1.1
16-083_ReferenceableGridCoverage_Extension.zipzip manage 101 K 24 Jun 2016 - 20:58 EricHirschorn GMLCOV 1.0 ReferenceableGridCoverage Extension, updated on June 24, 2016
17-089_WCS-core_2017-11-25.zipzip manage 99 K 03 Dec 2017 - 18:11 PeterBaumann WCS 2.1 draft (prepared for upcoming OGC TC vote)
2021-09-01_CovSwg_19123-3.pptxpptx 2021-09-01_CovSwg_19123-3.pptx manage 903 K 02 Sep 2021 - 08:59 PeterBaumann Coverages.SWG presenttion of 19123-3 draft
2021-10-21_GWF-21_OAPI-Coverages.pdfpdf 2021-10-21_GWF-21_OAPI-Coverages.pdf manage 1 MB 27 Oct 2021 - 13:04 PeterBaumann OAPI-Coverages overview
ISO_19123-1_for-FDIS-ballot.docxdocx ISO_19123-1_for-FDIS-ballot.docx manage 1 MB 22 Dec 2022 - 11:58 PeterBaumann ISO 19123-1 Abstract Coverage Model -- successfully passed DIS, now under FDIS ballot
ISO_19123-3_for-FDIS-ballot.docxdocx ISO_19123-3_for-FDIS-ballot.docx manage 919 K 22 Dec 2022 - 11:58 PeterBaumann ISO 19123-3 Abstract Coverage Processing Model -- successfully passed DIS, now under FDIS ballot
WCS-internal-organization.pngpng WCS-internal-organization.png manage 30 K 19 Jun 2019 - 11:18 PeterBaumann WCS-internal data organization
cis_1-1.zipzip manage 867 K 04 Apr 2017 - 10:18 PeterBaumann Coverage Implementation Schema 1.1 (adopted standard)
wcs-spec-hierarchy.pngpng wcs-spec-hierarchy.png manage 65 K 09 Nov 2020 - 13:19 PeterBaumann OGC coverage data and service standards overview diagram
wcs_2019-06-05.eapeap wcs_2019-06-05.eap manage 3 MB 19 Aug 2021 - 13:40 PeterBaumann Coverage data and service UML model (non-authoritative)
Topic revision: r56 - 16 Jun 2023, PeterBaumann
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