[Requests] SOS 2.0 request: nested observedProperties

I-Lin Kuo ilinkuo at usgs.gov
Tue Nov 30 17:43:55 EST 2010

Part A to be completed once.  Iterate Part B as needed.


1. Evaluator:
        I-Lin Kuo                       <ilinkuo at usgs.gov>

2. Submission: OGC 10-037 SOS 2.0 Candidate standard


1. Requirement: Allow SOS GetCapabilities Offering to advertise large 
lists of observedProperties

        The USGS would like to use SOS 2.0 for water quality data. In 
reviewing the SOS 2.0 specification for its appropriateness for use, we've 
discovered a potential scaling issue when the specification is appllied to 
USGS data. For water quality data, the USGS currently has over 4400 
parameters. The USGS term "parameter" corresponds to the OGC 
"observedProperty" term. If in a USGS water quality SOS service, we were 
to list the entire set of 4400+ observed properties, that would make the 
GetCapabilities document too large to handle. 
        In order to avoid this problem, we would like to handle 
observedProperty in a way analogous to the way that has been suggested for 
handling large Feature collections via nested documents, and also to add 
this to the set of suggestions that constitute a Large Dataset Handling 
Extension to the SOS 2.0 specification. 

2. Implementation Specification Section number: [General, #]

        1) The existing <observedProperty> child element is unaltered 
        2) Add an <observedPropertyCollectionRef> child element to 
sos:Offering, satisfying: 
                        * observedPropertyCollection is empty 
                        * it has mandatory attributes xlink:href, 
xlink:title, xlink:role 
                        * xlink:href must be resolvable. 
                        * xlink:title is informative and may be used for 
display purposes on the client 
                        * the value of xlink:role is 
        3) The document pointed to by 
observedPropertyCollection/@xlink:href must satisfy the following 
                        * the mimetype of the document is "text/xml" or 
any of the xml variants 
                        * the content of the document is an xml document 
with root element ObservedPropertyCollection satisfying: 
                                * the child elements of 
<ObservedPropertyCollection> are either <observedProperty> or 
<observedPropertyCollectionRef> obeying the rules above. Any document 
linked to by observedPropertyCollectionRef/@xlink:href must also obey the 
conditions of 3 

3. Criticality: [Major, Minor, Editorial, etc.]


4. Comments/justifications for changes: [Comments]

        Some means of advertising large lists of observed properties is 
necessary for water quality.

I-Lin Kuo
IT Specialist, Center for Data Analytics (CIDA)
USGS WI Water Science Center
Phone: 608-821-3895
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