This, below, is an intentional cross-posting of a classic geowankers'
sytle dialog on related semweb lists
For simplicity sake, I suppose we should post any substantive comments
on one of the lists below, not necessarily here - unless we want to fork
off some kind of local tangential threads.
Read the original post at the bottom first.
fwiw:
~mike
------- Original Message --------
Subject: Re: GeoSpatial vocabularies
Resent-Date: Tue, 07 Aug 2012 19:09:04 +0000
Resent-From: [email protected]
Date: Tue, 7 Aug 2012 12:08:34 -0700 (PDT)
From: Gannon Dick <[email protected]>
Reply-To: Gannon Dick <[email protected]>
To: Phil Archer <[email protected]>, Public GLD WG <[email protected]>,
"[email protected]" <[email protected]>
1. Couldn't find the proposal for this Group. How many imaginary
participants have signed up ?
2. "Paola's Razor" - with apologies to William of Occam/Law of Parsimony
- Paola Di Maio said: "... but as far as I know the democratic world
mandates
and promotes free speech in all its forms :-)". This is an important
entailment for geolocation systems. The (Statistical/RDF) Properties
(scalars) of a particular region must be integrated and
non-discriminatory. For example, the systemic location of the
University of Oxford cannot be broken down to the locations of the 38
Colleges and 6 PPH's. This is important because Mobile Devices are
points not regions. Forty-four Oxford University cell phones should
return the same location - an abstract rooftop called "Oxford
University" in something called Oxfordshire. This is real space, not
hyperspace.
3. The tiny little location range (ca. 4 inches for a satellite
photograph ) of Mobile Devices has be balanced with the radial metrics
of socio-political entities, otherwise the over magnification problem
leads to false conclusions. In any given region, (Population > Mobile
Devices) AND (Population > Households). The quantitative relation of
Mobile Devices and Households is unknowable. For personal privacy, back
up just a minute ... who told MS (Bing) and Google Earth they could map
my roof in 4" squares ?
4. The "picture" of locations as crystalline locations (close packing of
spheres) is also wrong, since there is a hyperspace distance between the
centers. As above, with two regions (Population[1] > Population[2]) OR
(Population[1] <= Population[2]).
5. The difficulty with writing RDF for locations is that the Classes
must all be scalars with units in a system (RDF) without scale. Regional
metrics cannot be fungible (like currency) because that type has
variable frequency. For example, suppose you knew the ratio of
Population to Housing Units for Oxfordshire and wanted to make a guess
at the food bill for an average household. So you tally the Meals Eaten
per Week (as a Household) ... you get a number of frequency spectra
depending on various "business" cases but vary the cost of food and you
get stock ticker looking noise. This uncertainty is the model's fault,
not the measurer's fault.
Is there a simpler way ? Yes, avoid the XKCD Trap by being only as
complex as you need to be and ("Paola's Razor", FEAR IT!) being
considerate of people not like you.
Have a look at this picture:
http://www.rustprivacy.org/2012/roadmap/gs-cell.png
The center of your Community [box] is the star in the middle. The
distance from the star to the box perimeter is how long it takes people
in your Community to get to work (point w). Other tasks (point t),
besides work (getting a haircut, shopping for groceries, etc.) are all
on the Society [circle]. Hyperspace permeates all - the outside box
being the boundary - or you can say Community is fixed in Society which
is floating around in Cyberspace. That's it. Now to put numbers on ...
FIPS (Federal Information Processing Standards) can be reduced to a Web
Domain Identifier.
For each County and County Subdivision, Population, Housing Units
(Occupied), Land Area, Water Area, Latitude, Longitude and Time Zone
(Some Counties are split - this is the Oxford University problem
above). The Census also provides an average commute to work, by
County. The uses for this take a little explanation ... In classical
Physics, Power = Work/Time and Speed = Distance/Time. In the real
world, The time required to get to the task "work" places an upper limit
on the power required to accomplish other tasks. This is a little hard
to wrap your head around, but remember you are talking about "local"
averages and indeed this "law" is locally true*. For every you with a
grocery store next door, there is someone else with the grocery store 10
feet past the office. The Census Bureau publishes the average commute
to work by County. As a practical matter multiply MTT by a speed 160
km/hr, 2 mph on foot, etc, and you get a relative estimate of the power
consumed which will not veer off into impossible to conceptualize
complex arithmetic.
An example "profile" for Rhode Island is here:
http://www.rustprivacy.org/2012/roadmap/profile-RI.txt
The "almost done" National Profile has almost 40,000 identifiers.
--Gannon
[*] This is how Lord Kelvin messed up the Age of the Earth. Hopefully
the University of Southampton has better engineers than the University
of Glasgow. Phil ? Any career ending thoughts for us ? :-)
----- Original Message -----
From: Phil Archer <[email protected]>
To: Public GLD WG <[email protected]>; "[email protected]"
<[email protected]>
Cc:
Sent: Monday, August 6, 2012 7:46 AM
Subject: GeoSpatial vocabularies
Having been involved with a number of conversations recently, and being
aware of many more, I am proposing a new Community Group around
vocabularies for describing locations.
See http://www.w3.org/community/groups/proposed/#locadd
Background
==========
This is hardly a new idea and the last thing I want to do is to fall
into the XKCD trap [1]. Nevertheless, we have different organisations
having similar but separate conversations at the moment, mostly born of
different use cases and perspectives. This is normal but I think some
sort of coordination could be beneficial.
GeoSPARQL
=========
The OGC has completed work on GeoSPARQL [2]. This is favoured by the
likes of (UK mapping agency) Ordnance Survey and has been produced
primarily by geospatial experts with an interest in linked data.
NeoGeo
======
A community effort has produced NeoGeo [3]. This is favoured by the
likes of (French mapping agency) IGN and has been produced primarily by
linked data experts with an interest in geospatial data.
The primary difference between GeoSPARQL and NeoGeo is in the way they
handle point, line and polygon literals. Both enjoy significant support
and implementation experience.
INSPIRE
=======
Is a European Commission Directive that legally obliges the Member
States of the European Union to publish environmental and geospatial
data using a common set of standards which are under various stages of
development [4].
ISA Programme Location Core Vocabulary
======================================
Produced by a working group chaired by the team responsible for the
development of INSPIRE under the auspices of a different part of the
European Commission, this very lightweight vocabulary includes
properties and classes for describing locations and for recording
addresses in a manner conformant with INSPIRE - a feature not shared by
vCARD for example. Now a work item of the W3C Government Linked Data WG
[5], the vocabulary needs further community review and refinement [6].
schema.org <http://schema.org/>
==========
Includes basic classes and properties for locations including:
- addresses (a clone of vCard) http://schema.org/PostalAddress
- lat/long (a clone of WGS84) http://schema.org/GeoCoordinates
- geoShape (including boc, circle, line & polygon)
http://schema.org/GeoShape
It inherits things like name, URL and description from schema.org/Thing
<http://schema.org/Thing> which are at least analogous to things like
Geographic Names and Geographic Identifiers.
schema.org includes containedIn but not, AFAICT, borders etc. The
schema.org location properties seem closely linked with event
vocabulary. Classes include Mountain, Body of Water, Continent etc.
The current list of proposed extensions to schema.org [7] does not
include anything in this space and there is no (visibly active)
discussion associated with schema.org and location.
W3C Point of Interest
=====================
I'm sorry to say that the Points of Interest WG [8] seems to have hit
the buffers so that the March 2012 draft [9] looks like being as far as
it gets. This just at a time when more and more data is being published,
a lot of it related to locations and, well, points of interest. The
ideas behind the POI WG remain as important as ever but it seems that a
new focus is necessary if that work is to be leveraged effectively.
Standards bodies
================
OGC and W3C are both willing to help if required but what actually *is*
required? That's what the proposed community group is to find out. When
we know that, we can look at where any work should be done. Like any
membership organisation, both W3C and OGC put the wishes of their
members first. Both bodies are very willing to work together.
Possible outcomes
=================
One possible outcome is a standard that is backwards compatible with
GeoSPARQL and NeoGeo and that combines aspects of both. The danger there
is that this would lead to an over-complex standard that could never be
fully implemented - which is about as big a pointless waste of time as
can be imagined. However, the two are close and common ground shouldn't
be hard to find.
At the other extreme is that everyone carries on in in their own way
and, well, people can pick and choose. This seems less than ideal to me.
If interoperability between data sets is important then we need to make
some effort to coordinate.
The gaps seem to be around linked-data friendly INSPIRE standards,
particularly wrt addresses, and in handling geometry literals that can
be huge (no one is talking about yet another way to define points lines
and polygons btw!).
What I hope the proposed group could achieve is:
- consensus on the use cases/gaps that need be filled;
- at least a rough solution that takes full account of the existing work
highlighted here.
If that can be done, the GLD WG's charter would allow it to take this
through the W3C Recommendations Track, assuming the continued support
and interest of the community. The WG itself does not have the resources
and geospatial expertise to see this through on its own.
If this interests you, do please join the Community Group at
http://www.w3.org/community/groups/proposed/#locadd and post your ideas.
Thank you
Phil.
[1] http://xkcd.com/927/
[2] http://www.opengeospatial.org/standards/geosparql
[3] http://geovocab.org/doc/neogeo/
[4] http://inspire.ec.europa.eu/index.cfm/pageid/2
[5] http://www.w3.org/2011/gld/
[6] http://philarcher.org/isa/locn-v1.00.html although officially I
should point you to http://joinup.ec.europa.eu/asset/core_location/home
[7] http://www.w3.org/wiki/WebSchemas/SchemaDotOrgProposals
[8] http://www.w3.org/2010/POI/
[9] http://www.w3.org/2010/POI/documents/Core/core-20111216.html
--
Phil Archer
W3C eGovernment
http://www.w3.org/egov/
http://philarcher.org <http://philarcher.org/>
+44 (0)7887 767755
@philarcher1
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