[apps-discuss] Appsdir review of draft-ietf-geopriv-relative-location
ht@inf.ed.ac.uk (Henry S. Thompson) Wed, 17 April 2013 15:02 UTC
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Date: Wed, 17 Apr 2013 16:02:44 +0100
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Cc: appsdir@ietf.org, iesg@ietf.org
Subject: [apps-discuss] Appsdir review of draft-ietf-geopriv-relative-location
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I have been selected as the Applications Area Review Team reviewer for this draft (for background on apps-review, please see http://www.apps.ietf.org/content/applications-area-review-team). Please resolve these comments along with any other Last Call comments you may receive. Please wait for direction from your document shepherd or AD before posting a new version of the draft. Document: draft-ietf-geopriv-relative-location Title: Relative Location Representation Reviewer: Henry S. Thompson Review Date: 2013-04-16 Summary: This draft is almost ready for publication as a Proposed Standard but has a few issues that should be fixed before publication Minor Issues: 3 The use of the phrases '"baseline" location' and '"reference" location' to mean the same thing (?) is confusing in the extreme (as is the fact that sometimes the phrase includes scare-quotes, but sometimes not). For example, in the following, what is meant to be the difference between the two highlighted phrases? "In particular, while it is possible to put all location information into the 'reference' location (leaving an ^^^^^^^^^ universally broad 'baseline'), location objects SHOULD NOT have all location information in the baseline location. Doing this ^^^^^^^^ would cause clients that do not understand relative location to incorrectly interpret the baseline location (i.e., the reference point) as the actual, precise location of the client." Furthermore wrt this passage, either I'm confused, or there's a mistake at the second highlighted point. I was expecting "relative", not "baseline" (or "reference"). After all, if all the information is in the baseline, then there is no information in the relative part, and so not processing it misses nothing??? Ah, repeated re-readings have uncovered the origin of the problem, further back: "A client that does understand this extension will interpret the location within the relative element as a refinement of the baseline location, which gives the reference location for the relative offset." I read that the first five times as if it were bracketed like this: [a refinement of [the baseline location, which gives the reference location for the relative offset]]. But you mean it as if it were bracketed like this: [a refinement of the baseline location], [which gives the reference location for the relative offset]. So, I suggest you rephrase the whole sentence along the following lines: "A client that does understand this extension will interpret the location within the relative element as a refinement of the baseline location. The resulting refined location then gives the reference location for the relative offset." With that change, the paragraph containing the first quote above (the para beginning "The baseline location SHOULD be general enough") is comprehensible, but still very dense. I know illustrations are hard when one is restricted to ASCII-art, but a pair of examples would be a great help here, where one obeys the rules, and is not understood wrongly by a non-extension-supporting app, but the other breaks the rules, and therefore liable to be interpreted wrongly by such an app. And, finally, perhaps just _after_ the example now at the end of this section, just a brief gloss along the lines of The baseline location, given by the first ca:civicAddress element, the first child of the gp:location-info, is a street address, to the level of detail of the house number (123). The reference location is [now the front door, something else if you fix the 5.1 issue below]. The actual location, which is still within the baseline building, is a point 100m east and 50m north [?] of the front door. 4.11.1 "An 'http:' or 'https:' URL MUST be used unless . . ." Wouldn't it be more in the spirit of 2119 to say "A URI with scheme other than 'http:' or 'https:' SHOULD NOT be used unless" ? 5.1 Civic PIDF with Polygon Offset [also at end of section 3] This example uses the ca:INT element, which as far as I can tell is only defined in the expired draft-rosen-geopriv-pidf-interior [1]. It would be better to adjust the example so that it uses elements and validates with schema documents all of which can be found in current RFCs. 5.2 Geo PIDF with Circle Offset Once the cut-and-paste error identified below in the 'Nits' section is fixed, the result has 4 schema-validity errors, all of which I presume should be straightforward to correct: ex5.xml:14:4: Invalid per cvc-complex-type.1.2.4 : element {http://www.opengis.net/gml}:radius not allowed here (5) in element {http://www.opengis.net/pidflo/1.0}:Circle, expecting {http://www.opengis.net/pidflo/1.0}:radius ex5.xml:25:6: Invalid per cvc-complex-type.1.2.4 : element {http://www.opengis.net/gml}:Circle not allowed here (1) in element {urn:ietf:params:xml:ns:pidf:geopriv10:relative}:offset, expecting {http://www.opengis.net/gml}:OrientableCurve,..., {http://www.opengis.net/gml}:LineString ex5.xml:25:6: Invalid per cvc-complex-type.1.3 : undeclared attribute {None}:srsName ex5.xml:28:3: Invalid per cvc-complex-type.1.2.4 : element {http://www.opengis.net/gml}:radius not allowed here (4) in element {http://www.opengis.net/gml}:Circle, expecting {http://www.opengis.net/gml}:pos, {http://www.opengis.net/gml}:pointProperty, {http://www.opengis.net/gml}:pointRep,$ Nits: 5.1, 5.2 [examples] These examples rely on schema documents which require moderately tedious indirection via the XML registry [2] to find -- it would be helpful if the references section at least included the relevant RFCs, at least 3863, 4479 and 5139. 5.2 <rel:urltype="image/png"> --> <rel:url type="image/png"> There are a number of spurious lines at the end of the example, which don't match anything at the beginning and render the whole thing non-well-formed: </gp:geopriv> </status> <timestamp>2003-06-22T20:57:29Z</timestamp> </tuple> ??? 6. Schema Definition The repeated pattern used for complex type definition in this schema doc is as follows: <xs:complexType name="relativeType"> <xs:complexContent> <xs:restriction base="xs:anyType"> <xs:sequence> ... </xs:sequence> <xs:anyAttribute namespace="##other" processContents="lax"/> </xs:restriction> </xs:complexContent> </xs:complexType> This is overly . . . complex and invites confusion, as it is strictly equivalent to the much simpler <xs:complexType name="relativeType"> <xs:sequence> ... </xs:sequence> <xs:anyAttribute namespace="##other" processContents="lax"/> </xs:complexType> Please simplify all your complex type definitions along these lines. [1] https://datatracker.ietf.org/doc/draft-rosen-geopriv-pidf-interior/ [2] http://www.iana.org/assignments/xml-registry/xml-registry.xml -- Henry S. Thompson, School of Informatics, University of Edinburgh 10 Crichton Street, Edinburgh EH8 9AB, SCOTLAND -- (44) 131 650-4440 Fax: (44) 131 650-4587, e-mail: ht@inf.ed.ac.uk URL: http://www.ltg.ed.ac.uk/~ht/ [mail from me _always_ has a .sig like this -- mail without it is forged spam]
- [apps-discuss] Appsdir review of draft-ietf-geopr… Henry S. Thompson
- Re: [apps-discuss] Appsdir review of draft-ietf-g… Martin Thomson
- Re: [apps-discuss] Appsdir review of draft-ietf-g… Henry S. Thompson