Copyright © 2011 Open Geospatial Consortium.
31 Some programmatic solution can certainly be designed, such as the validation tool being
aware of the data source of the data being validated and how to query it for missing information.
This would most likely take the form of a WFS service, and could be more easily facilitated by allowing for this content to be in-line in the document. An alternative is
some kind of WFS request inside the document to get the AIXM feature data via identifier would allow retrieval of the necessary information for validator
implementations that support this.
6.2 Validation Coverage
One goal of the validation work was to make the work on schematron rules for automated testing of DNES requirements more visible. This has been done by documenting which
requirements normative statements from the DNES have been covered through schematron rules created in OWS-8.
Due to resource constraints, primarily the statements from scenarios with high sponsor priority were considered. The following list shows the scenarios sorted in OWS-8
according to sponsor priority, in descending order:
1. Navaid unserviceable 2. Aerodrome closure
3. Runway closure 4. Other Event
5. Published special activity area – activation 6. Taxiway closure
7. Airport surface contamination 8. Published special activity area – creation
9. Ad-hoc ATS airspace – creation 10. Route portion closure
11. Route portion opening 12. New obstacle
13. Published ATS airspace - activation deactivation
Schematron rules cover general rules from the DNES as well as rules specific for the first four scenarios in the list. See the coverage tables in Annex A – Validation Coverage for
further details.
6.2.1 Gaps in Automatic Validation Rules
There are common situations where XML Schema and Schematron alone cannot provide automated validation for a given rule. This section lists these common situations.
Some normative statements require data that is not included in the document being validated, as discussed in the Handling External Information Needed to Test Rules
section above.
32
Copyright © 2011 Open Geospatial Consortium.
6.2.2 Status of the XML Schema Files
The validation tool also performs XML Schema validation, but the package had difficulty using the schema files as they were presented. This was circumvented by making local
manual changes to the schema files to allow Xerces the XML parser validation package used to use them:
●
Comments after the XML declaration
?xml version=1.0 encoding=UTF- 8?
but before the opening element caused a “Content is not allowed in prolog” validation error. This affected the following files which had comments moved to
below the schema element opening tag.
○
AIXM_Features.xsd
○
AIXM_DataTypes.xsd
○
AIXM_AbstractGML_ObjectTypes.xsd
●
ISO_19139_Schemas\gco\basicTypes.xsd caused the error “The targetNamespace of the referenced schema, currently http:www.opengis.netgml3.2, must be
identical to that of the including schema, currently http:www.isotc211.org2005gco”. This was due to a namespace clash with a
basicTypes.xsd file in the GML namespace. To resolve this locally the file name of the GCO XSD was changed to gco_basicTypes.xsd. This is likely indicative of
a problem in the validation software’s resolution of XSD resources, not in the XSD files themselves.
