[georss] multiple locations and time
Mikel Maron
mikel_maron at yahoo.com
Thu Mar 1 15:21:13 EST 2007
Brian,
Couldn't Takeoff and Landing be represented as two items, which can be associated together by sharing the same <link>?
<rss ...>
<channel>
<title>Today's
Flights</title>
<item>
<title>Flight
2202 Takeoff</title>
<description>non-stop flight from
Boston to San Jose</description>
http://airlines/flightdetails/2202
<xCal:dtstart>2007-03-07T11:00:00Z</xCal:dtstart>
<xCal:dtend>2007-03-07T11:05:00Z</xCal:dtend>
<georss:where>
<gml:Envelope>
<gml:lowerCorner>42.367157
-71.010054</gml:lowerCorner>
<gml:upperCorner>42.367157
-71.010054</gml:upperCorner>
</gml:Envelope>
</georss:where>
<georss:relationshiptag>Takeoff</georss:relationshiptag>
</item>
<item>
<title>Flight 2202 Landing</title>
<description>non-stop flight from Boston to San Jose</description>
http://airlines/flightdetails/2202
<xCal:dtstart>2007-03-07T16:45:00Z</xCal:dtstart>
<xCal:dtend>2007-03-07T17:15:00Z</xCal:dtendt>
<georss:where>
<gml:Envelope>
<gml:lowerCorner>37.361400
-121.928031</gml:lowerCorner>
<gml:upperCorner>37.361400
-121.928031</gml:upperCorner>
</gml:Envelope>
</georss:where>
<georss:relationshiptag>Landing</georss:relationshiptag>
</item>
</channel>
</rss>
-Mikel
----- Original Message ----
From: "Knoth, Brian D." <bknoth at mitre.org>
To: Mikel Maron <mikel_maron at yahoo.com>; Joshua Lieberman <josh at oklieb.net>; georss at lists.eogeo.org
Sent: Thursday, March 1, 2007 7:59:34 PM
Subject: RE: [georss] multiple locations and time
Mikel:
I've taken a look at the RSS source behind the temporal
mapping that you sent. As much as I agree with the philosophy of trying to use
what's available as much as possible, I just can't figure out how to use that
approach for the case I'm trying to develop. The example that you have provided
is simple enough that the single position and single time are both related
directly to the item, so they can be easily correlated. In other words, the time
says that the item is valid between begin and end. The W3C georss then gives the
position of that item. So, ok, while the item is valid, here is where it
is.
The problem I am addressing is a bit different.
The item has a lifetime (which can be expressed by xCal extensions),
and within that lifetime the item has a history, a current and a projected
collection of locations with their own time slices. I'm of the position (no pun
intended) that the location time slices must be associated directly with the
location and not loosely linked with the item.
Josh provided to me an excellent example of this using
<gml:history> to capture time with location, but it was defined within a
proprietary namespace and definition, and that's most likely the path we will
have to take. All I'm wondering is couldn't the geoRSS GML profile be
easily extended to also support this concept and provide foundational data
support for temporal mapping applications (such as what you've done with
worldkit)?
I think I've given something like this before, and I know
it is not currently supported, but it's kind of what I am looking
for:
<rss ...>
<channel>
<title>Today's
Flights</title>
<item>
<title>Flight
2202</title>
<description>non-stop flight from
Boston to San Jose</description>
http://airlines/flightdetails/2202
<xCal:dtstart>2007-03-07T11:00:00Z</xCal:dtstart>
<xCal:dtend>2007-03-07T17:00:00Z</xCal:dtstart>
<georss:where>
<gml:EnvelopeWithTimePeriod>
<gml:description>Takeoff</gml:description>
<gml:lowerCorner>42.367157
-71.010054</gml:lowerCorner>
<gml:upperCorner>42.367157
-71.010054</gml:upperCorner>
<gml:timePosition
indeterminatePosition="before">2007-03-07T11:00:00Z</gml:timePosition>
<gml:timePosition
indeterminatePosition="after">2007-03-07T11:05:00Z</gml:timePosition>
</gml:EnvelopeWithTimePeriod>
</georss:where>
<georss:where>
<gml:EnvelopeWithTimePeriod>
<gml:description>Landing</gml:description>
<gml:lowerCorner>37.361400
-121.928031</gml:lowerCorner>
<gml:upperCorner>37.361400
-121.928031</gml:upperCorner>
<gml:timePosition
indeterminatePosition="before">2007-03-07T16:45:00Z</gml:timePosition>
<gml:timePosition
indeterminatePosition="after">2007-03-07T17:15:00Z</gml:timePosition>
</gml:EnvelopeWithTimePeriod>
</georss:where>
</item>
</channel>
</rss>
I just don't see a clean way of representing this type of
information by decoupling the time periods from the locations and somehow
associating them at the <item> level.
brian
From: Mikel Maron
[mailto:mikel_maron at yahoo.com]
Sent: Wednesday, February 28, 2007
8:41 AM
To: Knoth, Brian D.; Joshua Lieberman;
georss at lists.eogeo.org
Subject: Re: [georss] WAS: GeoRSS Validation
Service? RETURNING TO: multiple locations and time
Hi
Brian
Don't want to belabor the issue, but I very much share your
interest in representing time and space,
and my inkling on the best way to
go is leveraging RSS time/event namespaces already in use.
Small pieces,
loosely joined, of simple targeted vocabularies. I sent some links in the
thread a few
weeks back, here's another demo of using the Upcoming.org
GeoRSS/Event feeds
http://worldkit.org/upcoming/
If you 'd like
to pursue this course, well, let's do it!
Mikel
-----
Original Message ----
From: "Knoth, Brian D."
<bknoth at mitre.org>
To: Joshua Lieberman <josh at oklieb.net>;
georss at lists.eogeo.org
Sent: Wednesday, February 28, 2007 12:28:06
PM
Subject: Re: [georss] WAS: GeoRSS Validation Service? RETURNING TO:
multiple locations and time
Josh,
If by Give-and-Take, you mean that I should go off and
implement my own
extension(s) or utilize some combination of existing
extensions for
time windows and locations (while providing a loose
referential linking
between them) to support what I need, then I feel I
have been very
accommodating this. These are the suggestions that I've
received and
I'm being forced to accept them because my original
recommendation to
this mailing list of simply allowing the GML
representation of space
with time in the geoRSS profile has been
discarded.
I just don't understand how an extension whose main purpose
which is to
represent location (ie, geoRSS:where) can ignore the fact that
stuff is
at a place at a specific time, usually for a period of time, and
then
at some other place for other period of time. This fact just seems
so
basic that to ignore it seriously limits the applicability of geoRSS
to
anything more than possibly just the world of blogging. GE does a
great
job of activating and deactivating things that are outside of
their
time windows when TimePeriods are specified in KML. I've heard
some
unsubstantiated rumors that GE may support geoRSS in the future -
if
that is the case, shouldn't the hooks at least be inserted into
geoRSS
now to begin preparing for that usage?
So you are absolutely
correct...I can build proprietary extensions and
mechanisms for supporting
this in our RSS feeds. I have felt, and still
strongly do feel, that the
proper place for this is within a maturing
RSS extension such as geoRSS
which, hopefully for its own adoption
sake, can provide the building blocks
necessary to support
functionality required by not only the Flikrs and
blogs, but also
Enterprise RSS as
well.
VR
brian
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