[Requests] WCS 2.0 comments

Clemens Portele portele at interactive-instruments.de
Mon Apr 12 13:43:32 EDT 2010


PART A


1. Evaluator: 

Clemens Portele, portele at interactive-instruments.de

2. Submission: 

09-110r2 (WCS_2.0_Core_Interface_Standard)
09-146 (GML_3.2.1_Application_Schema_for_WCS_2.0)


PART B.1


1. Requirement: 09-110r2, #1 / General; 09-146, #4


2. Implementation Specification Section number: 6 / general


3. Criticality: Major


4. Comments/justifications for changes: Requirement #1 does not seem to be aligned with the XML Schema. No XML element CoverageOffering could be found, i.e. the use of an Xpath expression in requirement #1 seems to be meaningless. Verify correctness of all Xpath expressions in 09-110r2 with respect to the normative XML Schema using sample XML files before submitting WCS 2.0 for vote.

The same applies to 09-146 (req #4).


PART B.2


1. Requirement: General


2. Implementation Specification Section number: General


3. Criticality: Major


4. Comments/justifications for changes: The standardisation target for the different requirement classes are not clear. 

The standardisation target type of the single conformance/requirements class in 09-110r2 seems to be an OGC Web Service (OWS). However, req 34/35 include clients. Consider to explicitly state the standardisation target type per requirements class as well as the direct and indirect dependencies. Remove clients from req 34/35 (create another requirements class if necessary).

For 09-146, Clause 2 implies that "implementations" are the standardisation target type, from the wording of the requirements this seems to imply that XML documents are the standardisation target type, i.e. "implementations" refers to XML instances, not to software components. This should be clarified. Again, consider to explicitly state the standardisation target type per requirements class as well as the direct and indirect dependencies. A consequence is that a software product cannot be compliant to the standard (09-146); it may claim however that it will only write compliant coverage instances in XML.  


PART B.3


1. Requirement: 09-146


2. Implementation Specification Section number: 4.1


3. Criticality: Minor


4. Comments/justifications for changes: The definition of coverage differs from the definiton in other OGC standards, e.g. GML, which uses the definition from ISO 19123: "feature that acts as a function to return values from its range for any direct position within its spatiotemporal domain". Change definition to the ISO 19123 definition.


PART B.4


1. Requirement: 09-146


2. Implementation Specification Section number: Figure 1


3. Criticality: Minor


4. Comments/justifications for changes: In GML 3.2, DomainSet and RangeSet are <<Union>>s, not <<Data Type>>s. Change stereotype to <<Union>>. Also, AbstractCoverage should be without a stereotype.


PART B.5


1. Requirement: 09-146


2. Implementation Specification Section number: Figure 1


3. Criticality: Minor


4. Comments/justifications for changes: The aggregation relationship between AbstractFeature and AbstractCoverage is unclear. This relationship is not discussed in the text and not part of the GML Schema (at least not as shown). Remove relationship from figure.


PART B.6


1. Requirement: 09-146


2. Implementation Specification Section number: Clause 6, in particular 6.2


3. Criticality: Major


4. Comments/justifications for changes: Align range structure encoding with SWE Common 2.0 (swe:DataRecord). Consistency and harmonisation between WCS and SWE Common is important, also with regard to future revisions of the coverage encoding of GML.

Also, ISO 19123 uses "rangeType" not rangeStructure as used in 09-146. Unless there is a good reason to deviate, use rangeType for consistency with the abstract specifications. 


PART B.7


1. Requirement: 09-146


2. Implementation Specification Section number: Examples


3. Criticality: Editorial


4. Comments/justifications for changes: uom-value "W/cm^2" should be "W/cm2"


PART B.8


1. Requirement: 09-146


2. Implementation Specification Section number: General


3. Criticality: Major


4. Comments/justifications for changes: Is there any reason to link the GML application schema to WCS 2.0 and use a namespace that starts with "http://www.opengis.net/wcs/2.0/"? Could this be a general GML application schema for grid coverages? This might make reuse of the application schema in other non-WCS-2.0-contexts more likely. 


-- 
Clemens Portele
portele at interactive-instruments.de
+49 228 9141073 (office)
+49 151 15298497 (mobile)

interactive instruments Gesellschaft für Software-Entwicklung mbH
Trierer Str. 70-72, 53115 Bonn, Germany
Geschäftsführer: Reinhard Erstling, Karla Hinzer, Clemens Portele, Bernd Weidner
Amtsgericht Bonn, HRB 3872



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