Open Geospatial Consortium

Submission Date: 2016-08-31

Approval Date: 2018-01-02

Publication Date: 2018-10-04

External identifier of this OGC® document: http://www.opengis.net/doc/IS/WCS-EO-AP/1.1

Internal reference number of this OGC® document: 10-140r2

URL for this OGC® document: http://docs.opengeospatial.org/is/10-140r2/10-140r2.html

PDF version (informative): http://docs.opengeospatial.org/is/10-140r2/10-140r2.pdf

Version: 1.1

Category: OGC® Implementation Standard

Editor: Peter Baumann, Stephan Meissl, Jinsongdi Yu

OGC® Web Coverage Service 2.0 Interface Standard - Earth Observation Application Profile

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Document type: OGC® Standard

Document subtype: Implementation

Document stage: Approved

Document language: English

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Table of Contents

i. Abstract

The OGC Web Coverage Service (WCS) Application Profile - Earth Observation (EO- WCS) defines a profile of WCS 2.0 [OGC 09-110r4] for use on Earth Observation data.

ii. Keywords

The following are keywords to be used by search engines and document catalogues.

ogcdoc, OGC document, wcs, profile, eo, earth observation, dataset, dataset series, stitched mosaic

iii. Preface

This WCS Application Profile for Earth Observation is an OGC Implementation Standard which relies on WCS 2.0 (the Core [OGC 09-110r4] plus selected extensions), the Coverages Implementation Schema (renamed from GML Application Schema - Coverages) [OGC 09-146r2], the Earth Observation Metadata Profile of Observations and Measurements [OGC 10-157r4], and GML 3.2.1 [OGC 07-036].

This document includes four annexes; only the first annex is normative.

The OGC® Abstract Specification does not require any changes to accommodate the technical contents of this (part of this) document.

Among the topics for future development are the following items:

  • Specify usage and content of EOWCS::Lineage in more detail.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. The Open Geospatial Consortium shall not be held responsible for identifying any or all such patent rights.

Recipients of this document are requested to submit, with their comments, notification of any relevant patent claims or other intellectual property rights of which they may be aware that might be infringed by any implementation of the standard set forth in this document, and to provide supporting documentation.

iv. Submitting organizations

The following organizations submitted this Document to the Open Geospatial Consortium (OGC):

Organization name(s)

  • Jacobs University Bremen

  • EOX IT Services GmbH

  • G.I.M. Geographic Information Management nv/sa

  • European Space Agency (ESA)

  • Spot Image

Additionally, rasdaman GmbH has made substantial contributions.

v. Submitters

All questions regarding this submission should be directed to the editor or the submitters:

Name Affiliation

Peter Baumann

Jacobs University Bremen, rasdaman GmbH

Jinsongdi Yu

Fuzhou University

Stephan Meissl <stephan.meissl@eox.at>

EOX IT Services GmbH

Christian Schiller

EOX IT Services GmbH

1. Scope

This OGC WCS Application Profile - Earth Observation Interface Standard - henceforth abbreviated as: WCS Earth Observation Application Profile (EO- WCS) - defines data structures and operations which together allow retrieval of Earth Observation coverages offered by a WCS 2.0 server.

EO- WCS, defines a profile of WCS 2.0 [OGC 09-110r4] for use on Earth Observation data. An Application Profile bundles several specifications and possibly adds additional requirements on an implementation. Extra requirements can be additions (for example, Dataset Series are introduced by this specification) or constraints (for example, coverages offered are required to include EO metadata).

EO-WCS provides the following specification elements.

  • Definition of specific Earth Observation coverages (EO Coverages) which have a latitude/longitude or projected x/y spatial extent and a temporal validity extent. EO Coverages are derived from Referenceable Grid Coverages and Rectified Grid Coverages as defined in the Coverage Implementation Schema (renamed from GML Application Schema - Coverages) [OGC 09-146r2]. Each EO Coverage has an EO metadata set [OGC 10-157r4] contained in its metadata which describes the coverage on hand on a higher semantic level.

  • Definition of a hierarchy which allows to group EO Coverages suitably for an efficient retrieval:

    • Datasets as plain EO Coverages (and, hence, accessible as coverages);

    • Stitched Mosaics as homogeneous collections of spatially non-overlapping subsets of Datasets, accessible themselves as coverages; and

    • Dataset Series as collections of Stitched Mosaics, Datasets, and/or Dataset Series; Dataset Series themselves are not coverages.

  • Bundling of several mandatory and optional WCS extensions for EO-WCS implementations.

2. Conformance

This document establishes the following requirements and conformance classes:

The standardization target of all requirements and conformance classes are EO-WCS implementations (currently servers).

Requirements and conformance test URIs defined in this document are relative to http://www.opengis.net/spec/WCS_application-profile_earth-observation/1.1/.

Conformance Class Abstract Test Suite (Normative) lists the conformance tests which shall be exercised on any software artifact claiming to implement EO-WCS.

3. Normative references

This OGC WCS Application Profile - Earth Observation specification consists of the present document and an XML Schema. The complete specification is identified by OGC URI http://www.opengis.net/spec/WCS_application-profile_earth-observation/1.1, the document has OGC URI http://www.opengis.net/doc/IS/WCS_application-profile_earth-observation/1.1.

The complete specification is available for download from http://www.opengeospatial.org/standards/wcs; additionally, the XML Schema is posted online at http://schemas.opengis.net/wcs/wcseo/1.1 as part of the OGC schema repository. In the event of a discrepancy between bundled and schema repository versions of the XML Schema files, the schema repository shall be considered authoritative.

The following normative documents contain provisions that, through reference in this text, constitute provisions of this specification. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. For undated references, the latest edition of the normative document referred to applies.

OGC: OGC 06-121r9, OGC Web Services Common Standard, version 2.0, 2010

OGC: OGC 09-146r2, OGC® Coverage Implementation Schema (renamed from OGC® GML Application Schema - Coverages), version 1.0, 2012
Conformance classes used: gml-coverage, gml, multipart, special-format

OGC: OGC 09-110r4, OGC® WCS 2.0 Interface Standard- Core: Corrigendum, version 2.0, 2012
Conformance classes used: core

OGC: OGC 11-053r1, OGC® Web Coverage Service Interface Standard - CRS Extension, version 1.0, 2014
Conformance classes used: crs, crs-gridded-coverage

OGC: OGC 12-039, OGC® Web Coverage Service Interface Standard - Scaling Extension, version 1.0, 2014
Conformance classes used: scaling

OGC: OGC 12-040, OGC® Web Coverage Service Interface Standard - Range Subsetting Extension, version 1.0, 2013
Conformance classes used: record-subsetting

OGC: OGC 12-049, OGC® Web Coverage Service Interface Standard - Interpolation Extension, version 1.0, 2014
Conformance classes used: interpolation

OGC: OGC 09-147r3, OGC® Web Coverage Service 2.0 Interface Standard - KVP Protocol Binding Extension - Corrigendum, version 1.0, 2013
Conformance classes used: get-kvp

OGC: OGC 09-149r1, OGC® Web Coverage Service 2.0 Interface Standard - XML/SOAP Protocol Binding Extension, version 1.0, 2010
Conformance classes used: soap

OGC: OGC 12-100r1, OGC® GML Application Schema - Coverages - GeoTIFF Coverage Encoding Profile, version 1.0, 2014
Conformance classes used: geotiff-coverage

OGC: OGC 14-100r2, OGC® CF-netCDF 3.0 encoding using GML Coverage Application Schema, version 2.0, 2015
Conformance classes used: CF-netCDF-1.6 GML encoding, CF-netCDF-1.6 data format, CF-netCDF-1.6 multipart data encoding

OGC: OGC 12-108, OGC® GML Application Schema - Coverages JPEG2000 Coverage Encoding Extension, version 1.0, 2015
Conformance classes used: jpeg2000-coverage

OGC: OGC 10-157r4, OGC® Earth Observation Metadata profile of Observations & Measurements, version 1.1, 2016
Conformance classes used: eop, sar, opt

4. Terms and Definitions

This document uses the standard terms defined in Subclause 5.3 of [OGC 06-121r9], which is based on the ISO/IEC Directives, Part 2, Rules for the structure and drafting of International Standards. In particular, the word "shall" (not "must") is the verb form used to indicate a requirement to be strictly followed to conform to this standard.

For the purposes of this document, the following additional terms and definitions apply. An arrow "→" indicates that the following term is defined in this Clause.

4.1. Coverage

digital representation of a spatio-temporally varying phenomenon as defined in [OGC 09-146r2]

4.2. Dataset

→ EO Coverage

Note
 A Dataset usually represents observations obtained by satellite instruments.

4.3. Dataset Series

collection of → EO Coverages

4.4. EO Coverage

Rectified Grid → Coverage or Referenceable Grid → Coverage having an → EO Metadata record and a WGS84 footprint

4.5. EO Metadata

→ EO Coverage’s metadata record

4.6. Stitched Mosaic

→ EO Coverage composed from subsets of one or more co-referenced → Datasets

4.7. EO Product

An EO Product contains one or more related → EO Product Datasets plus metadata and optionally auxiliary data like → EO Product Quicklooks.

4.8. EO Product Dataset

One or more files each containing one or more → EO Coverages.

4.9. EO Product Quicklook

A visual representation of a usually reduced → EO Product Dataset encoded in an image format. The → EO Product Dataset may combine different bands.

4.10. Lineage record

Data structure documenting an operation that has been applied to the → Coverage of which it is part

4.11. refers to

contains, in its → EO Metadata element as defined in [OGC 10-157r4], the → EO Metadata element

5. Conventions

5.1. UML notation

Unified Modeling Language (UML) static structure diagrams appearing in this specification are used as described in Subclause 5.2 of OGC Web Services Common [OGC 06-121r9].

5.2. Data dictionary tables

The UML model data dictionary is specified herein in a series of tables. The contents of the columns in these tables are described in Subclause 5.5 of [OGC 06-121r9]. The contents of these data dictionary tables are normative, including any table footnotes.

5.3. Namespace prefix conventions

The following namespaces are used in this document. The prefix abbreviations used constitute conventions used here, but are not normative. The namespaces to which the prefixes refer are normative, however.

Table 1. Namespace mappings
Prefix Namespace URI Description

xsd

http://www.w3.org/2001/XMLSchema

XML Schema namespace

ows

http://www.opengis.net/ows/2.0

OWS Common 2.0

gml

http://www.opengis.net/gml/3.2

GML 3.2.1

gmlcov

http://www.opengis.net/gmlcov/1.0

Coverages Implementation Schema 1.0

wcs

http://www.opengis.net/wcs/2.0

WCS 2.0

eop

http://www.opengis.net/eop/2.1

Earth Observation Metadata Profile of Observations and Measurements

opt

http://www.opengis.net/opt/2.1

Optical Earth Observation Metadata Profile of Observations and Measurements (extension of eop)

sar

http://www.opengis.net/sar/2.1

SAR Earth Observation Metadata Profile of Observations and Measurements (extension of eop)

wcseo

http://www.opengis.net/wcs/wcseo/1.1

WCS Application Profile - Earth Observation 1.1

scal

http://www.opengis.net/wcs/scaling/1.0 (schema uses http://www.opengis.net/WCS_service-extension_scaling/1.0)

WCS Scaling Extension

int

http://www.opengis.net/wcs/interpolation/1.0 (schema uses http://www.opengis.net/WCS_service-extension_interpolation/1.0

WCS Interpolation Extension

crs

http://www.opengis.net/wcs/crs/1.0

WCS CRS Extension

gmd

http://www.isotc211.org/2005/gmd

ISO 19139 Metadata

gmi

http://standards.iso.org/iso/19115/-2/gmi/1.0 or http://www.isotc211.org/2005/gmi

ISO 19139-2 Metadata

mdb

http://standards.iso.org/iso/19115/-3/mdb/1.0

ISO 19115-3 Metadata

5.4. Multiple representations

When multiple representations of the same information are given in a specification document these are consistent. Should this not be the case then this is considered an error, and the XML Schema shall take precedence.

6. EO data model

6.1. Overview

This Clause 6, together with Clauses 7 and 8, establishes the EO-WCS core requirements class, eowcs as well as the eowcs_geteocoverageset one where stated, particularly subclause 7.6.

The data model of this EO-WCS centers around the data structure of an Earth Observation coverage (EO Coverage), which is a coverage extended with EO Metadata [OGC 10-157r4] and bound to a location on the Earth. EO Coverages are a subtype of either GMLCOV::RectifiedGridCoverage or GMLCOV::ReferenceableGridCoverage.

Based on this EO Coverage concept (cf. Subclause 6.3), three main data elements are defined, as follows.

  • A Dataset is an EO Coverage, which can represent, for example, a hyperspectral 2D satellite scene or a 3D atmospheric model; cf. Subclause 6.4. A Dataset can be a Rectified Dataset or a Referenceable Dataset, depending on the type of EO Coverage it is derived from.

  • A Stitched Mosaic is a collection of EO Coverages referring to co-referenced Datasets; cf. Subclause 6.5. A Stitched Mosaic can be a Rectified Stitched Mosaic or a Referenceable Stitched Mosaic, depending on the type of EO Coverage it is derived from. A Stitched Mosaic can be interpreted (i.e. requested) as a single coverage.

  • A Dataset Series is a collection of coverages and/or Dataset Series; cf. Subclause 6.6. A Dataset Series can refer to any number of Datasets, Stitched Mosaics, and Dataset Series. A Dataset Series is not a coverage itself.

Note
 Use Case Examples (Informative) provides Use Cases to motivate the definition of these data elements.
Note
 Although named Dataset Series technically speaking it is a heterogeneous grouping of coverages and/or Dataset Series and can thus be used for any other concept like an EO Product containing multiple coverages with different resolutions as well.

Figure 1 informally symbolizes how the concepts of Dataset, Stitched Mosaic, and Dataset Series relate to each other spatio-temporally, as follows.

  • A - a Dataset with a particular validity in time.

  • B - a Stitched Mosaic; all its Datasets have a spatial extent contained in the Stitched Mosaic’s spatial extent and a timespan contained in the Stitched Mosaic’s time interval. The subsets contributing to the Stitched Mosaic do not overlap in space, but there may be empty (nil) areas.

  • C - the overall Dataset Series combining Datasets and Stitched Mosaics.

Dataset Series Conceptual View
Figure 1. Conceptual view of a Dataset Series with Stitched Mosaic and Dataset

Figure 2 contains the UML diagram defining classes (types) and their correlations in the EO-WCS.

6.2. EO Metadata

Every EO Coverage contains EO Metadata, consisting of an EarthObservation record as defined in the OGC Earth Observation Metadata Profile of Observations and Measurements [OGC 10-157r4] and a lineage describing the history of operations leading to the coverage on hand.

Requirement 1

/req/eowcs/eo-metadata-structure

A EOWCS::EOMetadata instance shall conform to Table 2, Figure 2, Figure 3, and the XML Schema being part of this standard.

Table 2. Components of EOWCS::EOMetadata structure
Name Definition Data type Multiplicity

earthObservation

EO metadata record for this coverage object

EOP::EarthObservation

one (mandatory)

lineage

History record describing an operation that has been applied to this object

EOWCS::Lineage

zero or more (optional)
UML Model
Figure 2. UML Model of WCS EO Application Profile Schema
Note
 Throughout this standard, eop: and EOP:: can be substituted by opt: and OPT:: or sar: and SAR::, respectively, as in [OGC 10-157r4] opt and sar are in the substitution group of eop.
UML Lineage class
Figure 3. UML Lineage class diagram
Note
 The lineage records are supposed to describe the history of processing steps that has led to the coverage on hand. As at the time of this writing there is no canonical format for such histories available in OGC, for the purpose of this specification no assumption is made about the contents of a lineage record, except that GetCoverage appends its request verbatim as an additional record (see Requirement 55 /req/eowcs/getCoverage-response-lineage-in-eo-metadata).

The footprint of an EO Coverage, which contains one or more bounding polygons to describe the region of valid data more accurately than the EO Coverage’s bounding box, is mandatory as opposed to [OGC 10-157r4].

Requirement 2

/req/eowcs/footprint-in-eo-metadata

The EOWCS::EOMetadata element of EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances shall contain an eop:EarthObservation/om:featureOfInterest/eop:Footprint element.
Note
 As per [OGC 10-157r4], the footprint is always given in WGS84.

6.3. EO Coverage

6.3.1. Overview

An EO Coverage is a coverage as defined in the Coverages Implementation Schema (renamed from GML Application Schema - Coverages) [OGC 09-146r2]. EO Coverages appear in two variants:

  • Rectified EO Coverages are derived from Rectified Grid Coverage as defined in [OGC 09-146r2]; and

  • Referenceable EO Coverages are derived from Referenceable Grid Coverage as defined in [OGC 09-146r2].

Requirement 3

/req/eowcs/eo-coverage-structure

EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances shall conform to Figure 2, Figure 3, and the XML Schema being part of this standard.

Note
 An EO Coverage can have any number of dimensions as long as it adheres to the requirements below. Particularly it needs a footprint bound to the Earth and a temporal validity.

6.3.2. EO Metadata

An EO Coverage has an EO Metadata record associated.

Requirement 4

/req/eowcs/eo-metadata-in-eo-coverage

EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances shall contain one metadata element of type EOWCS::EOMetadata.
Note
 Besides this specific metadata element there may be further metadata elements.
Note
 According to the rules of GML, a xlink:href URI to an accessible element of type EOWCS::EOMetadata can be provided instead of the element itself in any place of the XML Schema where such a metadata record appears.

The EO Metadata record associated with an EO Coverage contains a back reference to the coverage.

Requirement 5

/req/eowcs/eop-identifier-in-eo-metadata

The EOWCS::EOMetadata element of EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances shall contain an element eop:EarthObservation/eop:metadataProperty/eop:EarthObservationMetaData/eop:identifier whose first word (NCNAME type substring i.e. starting from it’s first character up to and excluding the first character which is not allowed in an NCName) is identical to the EO Coverage identifier.

Note
 Normally, this word (i.e. NCName) acting as coverage identifier will be the only contents of the eop:identifier string and thus both elements will be equal.

6.3.3. Spatio-temporal extent

The EO Coverage’s extent of valid data is given by its EO Metadata footprint, which refines the coverage’s envelope.

Requirement 6

/req/eowcs/footprint-inside-boundedBy

In EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances, all polygons listed in eop:EarthObservation/om:featureOfInterest/eop:Footprint element shall be geometrically contained in the bounding box of the gml:boundedBy element of the gml:Envelope.

Note
 By definition, the footprint is expressed in WGS84.

An EO Coverage has a time period of validity associated.

Requirement 7

/req/eowcs/phenomenonTime-in-eo-metadata

The EOWCS::EOMetadata element of a EOWCS::ReferenceableEOCoverage or EOWCS::RectifiedEOCoverage instance shall contain elements eop:EarthObservation/om:phenomenonTime/gml:TimePeriod/gml:beginPosition and eop:EarthObservation/om:phenomenonTime/gml:TimePeriod/gml:endPosition where beginPosition ≤ endPosition.

Note
 This typically is the time period where image acquisition has taken place.

Requirement 8

/req/eowcs/phenomenonTime-iso8601

For any given EO Coverage, its temporal validity values shall be expressed in ISO 8601 [2].

6.3.4. Range type

The range type of an EO Coverage is extended to include further useful information for example to know how to convert stored numbers to physical properties.

Requirement 9

/req/eowcs/rangeTypeExtension

If additional range type information is made available then the gmlcov:rangeType element of EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances shall contain wcseo:rangeTypeExtension elements either under the swe:DataRecord/swe:extension or each swe:DataRecord/swe:field/swe:Quantity/swe:extension element or both.

Requirement 10

/req/eowcs/rangeType-uom

In EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances, the code attribute of the swe:uom element of each swe:Quantity element in the gmlcov:rangeType element shall hold the unit of the measured physical property.

Note
 The data type is provided explicitly in the wcseo:rangeTypeExtension element or implicitly via the actual coverage encoding.

Requirement 11

/req/eowcs/rangeType-name

In EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances, the swe:identifier element of each swe:Quantity element under each swe:field element shall hold the URL-encoded identifier of the respective field (also referred to as band or channel) and the name attribute of each swe:field element shall hold the first word (NCNAME type substring i.e. starting from it’s first character up to and excluding the first character which is not allowed in an NCName) of the identifier of the respective field.
Note
 Typically the two values are identical. This requirement addresses cases where the identifier includes characters not allowed in NCName like :, @, $, %, &, /, +, ,, ;, or any whitespace characters or where it starts with a number, minus, or dot. For example an ID of gray band should use gray for the name attribute and gray%20band for the swe:identifier element.

Example: The following provides an example gmlcov:rangeType element including additional range type information for RGB generation on swe:DataRecord level as well as data conversion information on swe:Quantity level.

<gmlcov:rangeType>
  <swe:DataRecord definition="http://www.opengis.net/def/property/OGC-EO/0/opt/SpectralMode/PANCHROMATIC">
    <swe:extension>
      <wcseo:rangeTypeExtension>
        <wcseo:RGBgenerationHint>
          <wcseo:bandSequence>gray gray gray</wcseo:bandSequence>
          <wcseo:intervalFrom>1 4095</wcseo:intervalFrom>
          <wcseo:intervalTo>1 255</wcseo:intervalTo>
          <wcseo:type>http://sweet.jpl.nasa.gov/2.3/reprMathFunction.owl#Logarithmic</wcseo:type>
        </wcseo:RGBgenerationHint>
      </wcseo:rangeTypeExtension>
    </swe:extension>
    <swe:label>Gray Channel/Band</swe:label>
    <swe:field name="gray">
      <swe:Quantity definition="http://sweet.jpl.nasa.gov/2.3/propEnergyFlux.owl#SpectralRadiance">
        <swe:extension>
          <wcseo:rangeTypeExtension>
            <wcseo:dataSemantics>http://sweet.jpl.nasa.gov/2.3/stateSpectralBand.owl#Visible</wcseo:dataSemantics>
            <wcseo:dataType>http://www.opengis.net/def/dataType/OGC/0/unsignedShort</wcseo:dataType>
            <wcseo:dataType2dataSemantics>
              <wcseo:intervalFrom>1 4095</wcseo:intervalFrom>
              <wcseo:intervalTo>390.0000 780.0000</wcseo:intervalTo>
              <wcseo:type>http://sweet.jpl.nasa.gov/2.3/reprMathFunction.owl#Linear</wcseo:type>
            </wcseo:dataType2dataSemantics>
          </wcseo:rangeTypeExtension>
        </swe:extension>
        <swe:identifier>gray%20band</swe:identifier>
        <swe:label>Gray Channel/Band</swe:label>
        <swe:description>Gray Channel/Band</swe:description>
        <swe:nilValues>
          <swe:NilValues>
            <swe:nilValue reason="http://www.opengis.net/def/nil/OGC/0/unknown">0</swe:nilValue>
          </swe:NilValues>
        </swe:nilValues>
        <swe:uom code="W.m-2.sr-1.nm-1"/>
        <swe:constraint>
          <swe:AllowedValues>
            <swe:interval>0 4095</swe:interval>
            <swe:significantFigures>4</swe:significantFigures>
          </swe:AllowedValues>
        </swe:constraint>
      </swe:Quantity>
    </swe:field>
  </swe:DataRecord>
</gmlcov:rangeType>

6.3.5. Range set

Cells outside the footprint hold only nil values.

Requirement 12

/req/eowcs/range-set-of-eo-coverage

In EOWCS::ReferenceableEOCoverage and EOWCS::RectifiedEOCoverage instances, all cells whose locations are outside the EO Metadata footprint when both are evaluated in WGS84, shall contain nil values as defined in the bounding EO Coverage’s range type.

6.4. Dataset

A Dataset is an EO Coverage as symbolized in Figure 4. A Dataset is either a Referenceable Dataset or a Rectified Dataset, derived from EOWCS::ReferenceableEOCoverage or EOWCS::RectifiedEOCoverage, respectively.

Note
 Typically, a Dataset represents a (single- or multi-band) satellite/aerial image scene.

Requirement 13

/req/eowcs/dataset-structure

A EOWCS::ReferenceableDataset and a EOWCS::RectifiedDataset shall conform to Figure 2, Figure 3, and the XML Schema being part of this standard.

Dataset Conceptual View
Figure 4. Conceptual view of a Dataset: in referenced (left) and unreferenced coordinates (right)
Note
 This definition includes the "field-of-View" of a sensor, or "cut", according to sensor specific data specification at the resolution of the sensor (also referred to as Level-0 or Level-1 data).

6.5. Stitched Mosaic

6.5.1. Overview

A Stitched Mosaic is an identifiable, queryable, referenced EO Coverage as symbolized in Figure 5. A Stitched Mosaic is either a Referenceable Stitched Mosaic or a Rectified Stitched Mosaic, derived from EOWCS::ReferenceableEOCoverage or EOWCS::RectifiedEOCoverage, respectively.

Stitched Mosaics refer to one or more Datasets. All cells within a Stitched Mosaic which are not located inside any contributingFootprint of any of the contained Datasets carry nil values.

Stitched Mosaic Conceptual View
Figure 5. Conceptual view of a Stitched Mosaic: composed from Datasets (Stitched Mosaic bounding box dashed)

Requirement 14

/req/eowcs/referenceableStitchedMosaic-structure

EOWCS::ReferenceableStitchedMosaic instances shall conform to Figure 2, Figure 3, Table 3, Table 5, and the XML Schema being part of this standard.

Table 3. Components of EOWCS::ReferenceableStitchedMosaic structure
Name Definition Data type Multiplicity

dataset

Reference to a Referenceable Dataset referred to by the Stitched Mosaic on hand

EOWCS::DatasetReference

one or more (mandatory)

Requirement 15

/req/eowcs/rectifiedStitchedMosaic-structure

EOWCS::RectifiedStitchedMosaic instances shall conform to Figure 2, Figure 3, Table 4, Table 5, and the XML Schema being part of this standard.

Table 4. Components of EOWCS::RectifiedStitchedMosaic structure
Name Definition Data type Multiplicity

dataset

Reference to a Rectified Dataset referred to by the Stitched Mosaic on hand

EOWCS::DatasetReference

one or more (mandatory)
Table 5. Components of EOWCS::DatasetReference structure
Name Definition Data type Multiplicity

datasetId

Dataset referred to by the Stitched Mosaic on hand

WCS::CoverageId

one (mandatory)

contributingFootprint

Horizontal bounding polygon enclosing data areas of the Dataset contributing to the Stitched Mosaic on hand

EOP::Footprint

zero or one (optional)

The Dataset references of an EO Coverage shall be consistent with the coverage’s EO Metadata references.

Requirement 16

/req/eowcs/composedOf-in-stitched-mosaic

In EOWCS::ReferenceableStitchedMosaic and EOWCS::RectifiedStitchedMosaic instances with at least one eop:EarthObservation/eop:metaDataProperty/eop:Earth ObservationMetaData/eop:composedOf, the set of these elements shall be equal to the set of dataset identifiers of the Stitched Mosaic.

6.5.2. Spatio-temporal extent

A Stitched Mosaic is defined through a collection of spatially non-overlapping subsets of Datasets it refers to.

Requirement 17

/req/eowcs/contributingFootprint-inside-footprint

For all Stitched Mosaics sm referring to some Datasets d with an associated contributingFootprint, this contributingFootprint shall be geographically contained in the footprint of d.

Requirement 18

/req/eowcs/contributingFootprint-pairwise-disjoint

For all Stitched Mosaics sm referring to Datasets d1 and d2, with an associated contributingFootprint, the contributingFootprints of the d1 and d2 references shall be pair-wise disjoint.

Requirement 19

/req/eowcs/contributingFootprint-union-of-footprints

The footprint of a Stitched Mosaic shall be given by the union of the contributingFootprints of the Datasets this Stitched Mosaic refers to.

Requirement 20

/req/eowcs/dataset-domain-set-in-stitched-mosaic-domain-set

For all Datasets d referred to by some Stitched Mosaics sm, all cells of d as defined by the domain set of d shall be contained in the set of cells of sm as defined by the domain set of sm.

Datasets referred to by a Stitched Mosaic shall have aligned cell locations:

  • In case of Rectified EO Coverages, the grids of Datasets of a Stitched Mosaics shall have the same resolution.

    Requirement 21

    /req/eowcs/datasets-in-rectifiedStitcheMosaic-same-offsetVector

    All Datasets referred to by a Rectified Stitched Mosaic shall have identical values in the gml:offsetVector elements of their domain sets.

    Requirement 22

    /req/eowcs/rectifiedStitchedMosaic-offsetVector

    In a Rectified Stitched Mosaic instance, the value of the gml:offsetVector elements of the domain set shall be given by the corresponding values of the Rectified Datasets the Rectified Stitched Mosaic refers to.

  • In case of Referenceable EO Coverages, Datasets of Stitched Mosaics shall have aligned cell locations in overlapping areas.

    Requirement 23

    /req/eowcs/referenceableStitchedMosaic-domain-set

    For any pair d1 and d2 of Datasets referred to by a given Stitched Mosaic, the set of point locations in the geographic overlap of the d1 and d2 domain set shall be identical.

The temporal validity of Stitched Mosaics is defined by the temporal validities of the Datasets to which the Stitched Mosaic refers.

Requirement 24

/req/eowcs/temporal-validity-stitched-mosaic

For any given Stitched Mosaic, its temporal validity given by its eop:EarthObservation/om:phenomenonTime/gml:TimePeriod/gml:beginPosition and eop:EarthObservation/om:phenomenonTime/gml:TimePeriod/gml:endPosition elements in wcseo:EOMetadata shall be defined as the minimal time interval containing the temporal validities of all Datasets the Stitched Mosaic refers to.

6.5.3. Range type

Stitched Mosaics and their Datasets share the same range type.

Requirement 25

/req/eowcs/datasets-in-stitched-mosaic-same-range-type

For all Datasets d some Stitched Mosaic sm refers to the following shall hold: The range type of d is identical to the range type of sm.

6.5.4. Range set

The content of a Stitched Mosaic is given by the Datasets to which it refers; cells of a Stitched Mosaic with domain coordinates outside of any embedded Dataset’s contributingFootprint carry nil values (cf. Figure 6).

Requirement 26

/req/eowcs/nil-values-in-stitched-mosaic

If the domain set of a Stitched Mosaic contains locations which are not inside any contributingFootprint of any Dataset the Stitched Mosaic refers to then the nil value set of that Stitched Mosaic shall not be empty.

Requirement 27

/req/eowcs/range-values-of-stitched-mosaic

For a Stitched Mosaic sm its range values of cells with location p, expressed in any of the CRSs supported by sm, shall be given as follows:
- if p is located within the contributingFootprint of some Dataset d referred to by sm then it is the range value of d at p;
- if p is not located within the contributingFootprint of any Dataset d referred to by sm then it is one of the range values contained in the nil value set of sm.

6.6. Dataset Series

A Dataset Series is an identifiable, queryable collection of EO Coverages and Dataset Series.

Note
 Although named Dataset Series technically speaking it is a heterogeneous grouping of coverages and/or Dataset Series and can thus be used for any other concept like an EO Product containing multiple coverages with different resolutions as well.
Note
 A Dataset referred to by a Stitched Mosaic referred to by a Dataset Series is not per se referred to by that Dataset Series. However, it is allowed that such a Dataset is also referred to by the enclosing Dataset Series.
Dataset Series Conceptual View 2
Figure 6. Conceptual view of a Dataset Series referring to Datasets and Stitched Mosaics (Dataset Series domain boundary dashed)

Requirement 28

/req/eowcs/datasetSeries-structure

A EOWCS::DatasetSeries shall conform to Figure 2, Figure 3, Table 6, and the XML Schema being part of this standard.

Table 6. Components of EOWCS::DatasetSeries structure
Name Definition Data type Multiplicity

datasetSeriesId

Identifier of the Dataset Series on hand

NCName

one (mandatory)

footprint

Horizontal bounding polygon enclosing valid data areas of the Dataset Series

EOP::Footprint

one (mandatory)

timePeriod

Temporal period of validity of all data in the Dataset Series

GML::TimePeriod

one (mandatory)

metadata

EO Metadata of the Dataset Series on hand

ows:Metadata

zero or more (optional)

referenceableStitchedMosaic

Referenceable Stitched Mosaic to which the Dataset Series on hand refers

WCS::CoverageId

zero or more (optional)

rectifiedStitchedMosaic

Rectified Stitched Mosaic to which the Dataset Series on hand refers

WCS::CoverageId

zero or more (optional)

referenceableDataset

Referenceable Dataset to which the Dataset Series on hand refers

WCS::CoverageId

zero or more (optional)

rectifiedDataset

Rectified Dataset to which the Dataset Series on hand refers

WCS::CoverageId

zero or more (optional)

datasetSeries

Dataset Series to which the Dataset Series on hand refers

EOWCS::datasetSeriesId

zero or more (optional)
Note
 A Dataset Series and a Stitched Mosaic contained therein may both refer to the same Dataset.

The spatial extent of a Dataset Series shall enclose the spatial extents of all Stitched Mosaics, Datasets, and Dataset Series the Dataset Series refers to.

Requirement 29

/req/eowcs/footprint-in-datasetSeries

The footprint of a Dataset Series instance shall enclose the union of the footprints of all Stitched Mosaics, Datasets, and Dataset Series the Dataset Series refers to, expressed in WGS84.

Note
 As opposed to Stitched Mosaics, Dataset Series do not require disjointness of the EO Coverages to which they refer.

The temporal validity of a Dataset Series is defined by the union of the temporal validities of all Stitched Mosaics, Datasets, and Dataset Series to which the Dataset Series refers.

Requirement 30

/req/eowcs/timePeriod-in-datasetSeries

For any given Dataset Series, the timePeriod element shall enclose the temporal validities of all Stitched Mosaics, Datasets, and Dataset Series the Dataset Series refers to, expressed in ISO 8601 [2].

A Dataset Series has an EO Metadata record associated.

Requirement 31

/req/eowcs/metadata-in-datasetSeries

A Dataset Series instance shall contain one metadata element of type EOWCS::EOMetadata.

Note
 A Dataset Series may contain multiple metadata elements holding the metadata in different formats. Explicitly supported metadata elements are eop:EarthObservation, gmd:MD_Metadata, gmi:MI_Metadata, mdb:MD_Metadata, or ows:Reference or any element in the substitutionGroup of any of these.

A Dataset Series shall not refer to any Dataset Series that refers to it either directly or via other Dataset Series i.e. there shall be no circular references.

Requirement 32

/req/eowcs/nocircularreference-of-datasetSeries

A Dataset Series shall only refer to Dataset Series that do not refer to the Dataset Series at hand either directly or via other Dataset Series.

Example: The following XML fragment shows a DatasetSeries instance.

<?xml version="1.0" encoding="UTF-8"?>
<wcseo:DatasetSeries xmlns:ows="http://www.opengis.net/ows/2.0" xmlns:gml="http://www.opengis.net/gml/3.2" xmlns:wcs="http://www.opengis.net/wcs/2.0" xmlns:wcseo="http://www.opengis.net/wcs/wcseo/1.1" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.opengis.net/wcs/wcseo/1.1 http://schemas.opengis.net/wcs/wcseo/1.1/wcsEOAll.xsd">
  <wcseo:DatasetSeriesId>someDatasetSeries1</wcseo:DatasetSeriesId>
  <eop:Footprint gml:id="footprint_someDatasetSeries1">
    <eop:multiExtentOf>
      <gml:MultiSurface gml:id="multisurface_someDatasetSeries1" srsName="EPSG:4326">
        <gml:surfaceMembers>
          <gml:Polygon gml:id="polygon_someDatasetSeries1">
            <gml:exterior>
              <gml:LinearRing>
                <gml:posList>43.516667 2.1025 43.381667 2.861667 42.862778 2.65 42.996389 1.896944 43.516667 2.1025</gml:posList>
              </gml:LinearRing>
            </gml:exterior>
          </gml:Polygon>
        </gml:surfaceMembers>
      </gml:MultiSurface>
    </eop:multiExtentOf>
  </eop:Footprint>
  <gml:TimePeriod gml:id="someDatasetSeries1_timeperiod">
    <gml:beginPosition>2008-03-13T00:00:00.000</gml:beginPosition>
    <gml:endPosition>2008-03-13T23:59:59.999</gml:endPosition>
  </gml:TimePeriod>
  <ows:Metadata>
    <wcseo:EOMetadata>
      <ows:Reference xlink:href="http://www.someCatalogue.org/eop-metadata-from-someDatasetSeries1" xlink:role="http://standards.iso.org/iso/19115/-3/mdb/1.0" xlink:title="ISO 19115-3 Metadata" />
    </wcseo:EOMetadata>
  </ows:Metadata>
  <wcseo:rectifiedDataset>
    <wcs:CoverageId>someEOCoverage1</wcs:CoverageId>
  </wcseo:rectifiedDataset>
</wcseo:DatasetSeries>

7. EO service model

7.1. Overview

This Clause defines request types and their responses for operations on EO Coverages. EO Coverages can be offered by a WCS server alongside with any other type of coverage. Behavior of the service on non-EO Coverages remains unchanged.

7.2. GetCapabilities operation

7.2.1. GetCapabilities request

The GetCapabilities request is extended over WCS Core [OGC 09-110r4] as follows:

  • In the sections request parameter, values "DatasetSeriesSummary" and "CoverageSummary" are allowed in addition to those defined in OWS Common [06-121r9].

Requirement 33

/req/eowcs/getCapabilities-request-sections

If a GetCapabilities request contains an ows:Sections element then this element shall contain ows:Section elements with the values defined in OWS Common, or "DatasetSeriesSummary", or "CoverageSummary".
Dependency: [OGC 06-121r9] clause 7.3.3

7.2.2. GetCapabilities response

The GetCapabilities response is extended over WCS Core [OGC 09-110r4] as follows:

  • There is an additional DatasetSeriesSummary section reporting identifiers of Dataset Series offered by the service on hand;

  • There is an optional constraint CountDefault specifying the maximum number of CoverageDescription and DatasetSeriesDescription elements reported in a DescribeEOCoverageSet response; and

  • For the eowcs_geteocoverageset conformance class there is an additional <wcseo:wcseoMetadata element inside the wcs:Extension element of the wcs:ServiceMetadata element to specify default and supported package formats for the GetEOCoverageSet operation.

Note
 An EO-WCS server may choose to not report, in the CoverageSummary section of a GetCapabilities response, the identifiers of Stitched Mosaic coverages referred to by some Dataset Series and the identifiers of Dataset coverages referred to by some Stitched Mosaic or Dataset Series.

In a GetCapabilities response, a server announces availability of this EO-WCS like an extension.

Requirement 34

/req/eowcs/getCapabilities-response-conformance-class-in-profile

A WCS service implementing this extension shall include the following URI in a Profile element in the ServiceIdentification in a GetCapabilities response: http://www.opengis.net/spec/WCS_application-profile_earth-observation/1.1/conf/eowcs

Requirement 35

/req/eowcs_geteocoverageset/getCapabilities-response-conformance-class-in-profile

A WCS service implementing the eowcs_geteocoverageset conformance class of this extension shall include the following URI in a Profile element in the ServiceIdentification in a GetCapabilities response: http://www.opengis.net/spec/WCS_application-profile_earth-observation/1.1/conf/eowcs_geteocoverageset

Requirement 36

/req/eowcs/getCapabilities-response-structure

The response to a successful GetCapabilities request shall consist of a data structure as defined in Figure 7, Table 7, and the XML Schema being part of this standard.
Dependency: [OGC 09-110r4] Clause 8 (http://www.opengis.net/doc/IS/wcs-core-2.0.1/clause/8)