- From: Jeremy Tandy <jeremy.tandy@gmail.com>
- Date: Sat, 11 Mar 2017 10:05:02 +0000
- To: Bill Roberts <bill@swirrl.com>
- Cc: Andrea Perego <andrea.perego@ec.europa.eu>, Linda van den Brink <l.vandenbrink@geonovum.nl>, SDW WG Public List <public-sdw-wg@w3.org>
- Message-ID: <CADtUq_3G+N4_hXyM73wRHJ+uOoBOKT9mKbAEqtriOx5=2-E+Fw@mail.gmail.com>
Hi Bill - just one more thing (again!) ... I was talking to a colleague of mine earlier this week about how he's publishing spatial data on the Web; making use of GeoJSON, elastic-search, open layers etc. All good "modern" webby stuff. One of the bits of advice he gave was: "keep your data structures FLAT (avoid nesting/embedded objects; as per OGC GML Simple Features Profile) - this makes it easier for users to work with in existing tools (e.g. ElasticSearch)" He refers to the structures in GeoJSON [1] "properties" object (see 3.2 Feature Object [2]) and (I would assume) any "foreign members" [3]. This makes it easier to import the GeoJSON documents into elastic search etc. (I think that's what he said) The OGC's GML Simple Features Profile [4] defines three levels of compliance: SF-0, SF-1 and SF-2 - each of which become progressively less restrictive profiles from 0 to 2. Above 2 you're using everything that GML has; kitchen sink and all! I wonder if these notions of profiling for interoperability might be a useful inclusion in BP10? section "2.1 Introduction" provides a good starting point (but then I suppose that's the point). Jeremy [1]: https://tools.ietf.org/html/rfc7946 [2]: https://tools.ietf.org/html/rfc7946#section-3.2 [3]: https://tools.ietf.org/html/rfc7946#section-6.1 [4]: http://portal.opengeospatial.org/files/?artifact_id=42729 On Sat, 11 Mar 2017 at 09:29 Jeremy Tandy <jeremy.tandy@gmail.com> wrote: > Thanks Bill. > > On Sat, 11 Mar 2017 at 09:18 Bill Roberts <bill@swirrl.com> wrote: > > Hi Jeremy > > Good idea - I think it would be good to include something about addresses > and geocodes as a way of encoding location. I'll try to incorporate > something on that. > > > > On 11 March 2017 at 09:08, Jeremy Tandy <jeremy.tandy@gmail.com> wrote: > > Hi Bill. > > > Given that Andrea is talking about _geometries_ in BP8, we seem to have a > gap with regard to _other_ mechanisms to describe location; e.g. addresses > and geocodes (postal codes etc., geohashes [1] and, I think worth > mentioning explicitly, W3W [2]). > > > In you discussion of “how to encode spatial data” I think it is worth > calling these mechanisms out specifically, and referring to Andrea’s work > on geometries in BP8. > > > Given Andrea's involvement with the ISA Programme Location Core Vocabulary > [3] (which defines locn:Address), he may have some useful contributions > here too. > > > Addresses are mentioned in the following use cases: > > - 4.5 Harvesting of Local Search Content > - 4.9 Enabling publication, discovery and analysis of spatiotemporal > data in the humanities > - 4.13 Publication of air quality data aggregations > > > Strangely, we don’t have any requirements that mention addresses. > > > I’m also reminded of the Discrete Global Grid System (DGGS) standard being > prepared by OGC [4] which will … For example, HEALPix (“Hierarchical Equal > Area isoLatitude Pixelization”) grids, an indexing system used for DGGS, > are useful for EO data because each cell is uniquely identified and has > equal-area (at that level in the grid) so that you don’t need to re-sample > when comparing cell properties; the value of each cell is directly > comparable. DGGS and HEALPix are (were?) referenced in the EO-QB work of > our group. > > > That said, I don’t think the DGGS is formally approved as a standard, so > it may only warrant a note - or no mention at all. I doubt it meets our > criteria for “best practice in the wild”. It also looks a little complex > from my quick scan of the OGC doc. > > > There are also clearly a large number of other coding systems for > geographical and administrative areas & places. I’ll try to cover referring > to these types of things in BP14 concerning linking. > > > Given the short amount of time available before our intended “freeze” (on > Wed 15-Mar) of the BP doc for next WD release, I’d be content to push these > changes into the work plan for the next sprint. > > > Jeremy > > > > [1]: https://en.wikipedia.org/wiki/Geohash > > [2]: http://what3words.com > > [3]: https://www.w3.org/ns/locn# > > [4]: public draft: OGC #15-104r3 > https://portal.opengeospatial.org/files/66643 > > > > >
Received on Saturday, 11 March 2017 10:05:46 UTC