- From: Graham Klyne <GK@ninebynine.org>
- Date: Tue, 24 May 2011 21:29:11 +0100
- To: Carl Reed <creed@opengeospatial.org>
- CC: martin <martin@ics.forth.gr>, public-prov-wg@w3.org
Carl, Martin, and all, I think we're all broadly agreed in principle. So it comes down to what we actually have to say about location? Some particular topics I pick out of the discussion: - a location is an extent in space - location may be expressed with respect to any frame of reference, which may be terrestrial (or other planet based), or based (ultimately) on some arbitrary object - a frame of reference may occur at scales ranging from atomic to galactic and beyond - location may be expressed within its frame of reference by a metric scheme (coordinates, etc.) or by qualitative relation to characteristic features of the reference object. There's one thing in Martin's description I'd like to question: "Typically a location is a physically fixed point"; i.e. the reference to a "point". I suspect this was not meant to imply a location can be a point, though it is common to see an extent implied by some (unspecified) proximity to a given point (e.g. saying one's home lies at a given map reference). While this may be a common usage, I don't think it should form part of our definition of location. And if we do need to express point locations as well as extents, I think that needs careful handling. #g -- Carl Reed wrote: > Martin - > > All you state is correct. Since then, the OGC definition work in the has > gone much more "relative" :-) This because we now have folks > implementing OGC standards for brain scan applications, blood > circulatory systems, the moon, Mars, inside buildings (local engineering > CRS) and so forth. > > However, please note that a CRS does not mean earth centric! A CRS can > be an engineering coordinate system for a building design, local such as > in surveying, dynamic such as for moving satellite platforms, and so forth. > > There is a very interesting ISO standards that I have been involved in > on ubiquitous location and spatial reference systems. The are looking at > a model that allows for easy transition say from the usual earth centric > reference system (such as WGS 84-2d) into a shipboard reference and so > forth. > > Cheers > > Carl > > ----- Original Message ----- From: "martin" <martin@ics.forth.gr> > To: "Graham Klyne" <GK@ninebynine.org> > Cc: "Carl Reed" <creed@opengeospatial.org>; <public-prov-wg@w3.org> > Sent: Tuesday, May 24, 2011 11:18 AM > Subject: Re: PROV-ISSUE-6 (define-location): Definition for Concept > 'Location' [Provenance Terminology] > > >> I agree with the points given by Graham, with minor exceptions. >> The ISO21127 elaboration is not a specialization of the OGC definition >> for >> a community, just the opposite. When we discussed in the CRM working >> Group adopting the OGC definition, >> we found it too narrow because it seems to be restricted to locations >> that can >> be expressed in coordinate reference systems and geographic-scale, >> but ISO21127 explicitly intended to comprise >> OPENGIS at that time, in particular for dealing with relative >> coordinate systems. >> >> We found that references to locations in terms of characteristic >> features of an object, such as >> "bow of a ship", "inner side of a wedding ring" "room G161" "front of >> a house" are not only culturally but also technically >> important. They are referred to in ontological literature as segments, >> sections, portions or parts. >> There are elaborate ontologies of such kind. In the proceedings of the >> ER Conference series, >> many of these are published. >> >> This is exactly example (2) by Graham below, and I strongly support it. . >> >> I'd suggest something like that: >> >> "A location is an identifiable extent in space, in particular on the >> surface of the earth, in the sense of physics. >> Typically a location is a physically fixed point, typically on the >> surface of the >> Earth, though locations can be relative to other, local or global >> non-earth centric coordinate reference systems >> or be relative to persistent features on material objects other than >> the earth. Non-earth centric coordinate reference systems may be >> fixed on persistent mobile material objects." >> >> cheers, >> >> martin >> >> >> On 5/24/2011 1:33 PM, Graham Klyne wrote: >>> I think the notion of location should be as generic as possible. >>> >>> To this end, I'd like to pose an additional example, which comes from >>> a real scenario I've worked with, which suggests possible further uses >>> of location provenance. >>> >>> I raise this because I think it's important that whatever definition >>> we adopt for location does not rule out using the information suggested >>> by this use case as part of a record of provenance information. >>> >>> ... >>> >>> Researcher H is investigating genomics in Drosophila (fruit flies), >>> specifically genetic factors affecting spermatogenesis that may cause >>> sterility. To this end, she creates in situ hybridization >>> (http://en.wikipedia.org/wiki/In_situ_hybridization) images of >>> Drosophila testes. >>> Location information arises in a number of different ways: >>> >>> (1) starting from a microscopic image of testes treated to reveal >>> gene expression, the researcher looks for occurrences of interesting and >>> clearly exposed gene expression patterns. These occurrences are >>> recorded as a slide number and a coordinate location within the slide >>> image. >>> >>> (2) the spatial location of the gene expression within the testis >>> structure gives a direct visual indication of the sperm development >>> stage >>> at which a target gene is being expressed. This location is observed >>> and recorded as a keyword from a controlled vocabulary that relates the >>> gene expression to a developmental stage. >>> >>> As well as creating microscopic images, the tissue samples are >>> subjected to a real-time PCR process >>> (http://en.wikipedia.org/wiki/Polymerase_chain_reaction) that gives a >>> quantitative indication of the levels of a particular gene expression >>> product present in a sample. PCR is a batch process, where >>> preparations based on different samples (targetting different genes, >>> or different >>> Drosophila species) are placed into different wells in a tray. This >>> leads to: >>> >>> (3) The PCR analyzer presents by reference to the location of the >>> various wells (identified by label or row/column position). The well >>> locations are in turn linked to details of the sample that has been >>> placed in that well. >>> >>> Of these examples, I think that (1) and (3) are definitely part of >>> the provenance information for a result. (2) is less clear, and I'd >>> judge >>> it to be part of the data rather than provenance information. But >>> researcher H has also performed some follow-on research to analyzes >>> particular spatial patterns of gene expression, in which the >>> location-based developmental stage might conceivably be considered to be >>> provenance information, in the sense of where the phenomenon was >>> observed to occur. >>> >>> #g >>> -- >>> >>> >>> Carl Reed wrote: >>>> >>>> Martin - >>>> >>>> A shorter version as defined in ISO 19112 and used by the OGC (since >>>> this was a jointly developed definition) is: >>>> >>>> Location: Identifiable geographic place [ISO 19112]. Typically a >>>> location is a physically fixed point, typically on the surface of the >>>> Earth, though locations can be relative to other, non-earth centric >>>> coordinate reference systems. >>>> >>>> I also noticed that the the European INSPIRE community working on >>>> cultural heritage sites are using CIDOC/21127 as well as additional OGC >>>> references, such as the URN syntax for spatial reference systems. >>>> >>>> Suffice to say, the definition for location in 21127 is a community >>>> elaboration of the more general OGC/ISO definition. We may need some >>>> such additional clarification for the provenance work - such as >>>> dealing with data provenance for articles, maps, charts, etc for the >>>> moon, >>>> Mars, and so forth. >>>> >>>> Regards >>>> >>>> Carl >>> >>> >>> >> >> >> -- >> >> -------------------------------------------------------------- >> Dr. Martin Doerr | Vox:+30(2810)391625 | >> Research Director | Fax:+30(2810)391638 | >> | Email: martin@ics.forth.gr | >> | >> Center for Cultural Informatics | >> Information Systems Laboratory | >> Institute of Computer Science | >> Foundation for Research and Technology - Hellas (FORTH) | >> | >> Vassilika Vouton,P.O.Box1385,GR71110 Heraklion,Crete,Greece | >> | >> Web-site: http://www.ics.forth.gr/isl | >> -------------------------------------------------------------- >> >> > >
Received on Tuesday, 24 May 2011 20:30:01 UTC