[georss] Time and Space

[Knoth, Brian D.]

Raj,

I guess I should have specified our more general problem first, and
then you might see why we extended our use of GML geoRSS to handle it
the way we did.

Ok, so the first problem: We need to be able to specify multiple
time/space parameters for any particular RSS item. Imagine an RSS feed
of flight information, where each item represents a particular flight.
That flight will be on different stations at different times that we
may want to represent in this RSS feed. In this case, capturing the
time information separate from the spatial information is not adequate.
Here is an example feed:

<rss version="2.0">
	<channel>
		<title>Flight Information RSS</title>
		<description>Today's Flights</description>
		<link>http://somelink...</link>
		<item>
			<title>Flight 1995</title>
			<link>http://..flightdetails</link>
			<description>some desc</description>
			<guid
isPermaLink="false">id:flight-0A05000760l02yz</guid>
			<pubDate>2006-03-02T20:36:12Z</pubDate>
			<georss:where
xmlns:georss="http://www.georss.org/georss">
				<gml:TimePeriod
xmlns:gml="http://www.opengis.net/gml">
	
<gml:begin>2006-06-12T05:00:00Z</gml:begin>
	
<gml:end>2006-06-12T05:30:00Z</gml:end>
				</gml:TimePeriod>
				<gml:Envelope
xmlns:gml="http://www.opengis.net/gml">
					<gml:lowerCorner>43.8944
-123.5270</gml:lowerCorner>
					<gml:upperCorner>44.3444
-122.9002</gml:upperCorner>
				</gml:Envelope>			
			</georss:where>
			<georss:where
xmlns:georss="http://www.georss.org/georss">
				<gml:TimePeriod
xmlns:gml="http://www.opengis.net/gml">
	
<gml:begin>2006-06-12T08:00:00Z</gml:begin>
	
<gml:end>2006-06-12T09:00:00Z</gml:end>
				</gml:TimePeriod>
				<gml:Envelope
xmlns:gml="http://www.opengis.net/gml">
					<gml:lowerCorner>47.3900
-117.9881</gml:lowerCorner>
					<gml:upperCorner>47.8399
-117.3206</gml:upperCorner>
				</gml:Envelope>			
			</georss:where>
		</item>
		<item>
			<title>Flight 2099</title>
			<link>http://..flightdetails</link>
			.
			.
			.
		</item>
		.
		.
		.
	</channel>
</rss>

So, as you can see, keeping time defined as close to space as possible
is very important to us (and I would imagine anyone who is going to
want to similar types of things with RSS). I would think that extending
the GML geoRSS definition to include time would solve both the multiple
spatial problem and time/space problem at once. Do you agree?

Thanks,
brian


-----Original Message-----
From: georss-bounces at lists.eogeo.org
[mailto:georss-bounces at lists.eogeo.org] On Behalf Of Raj Singh
Sent: Monday, February 12, 2007 1:36 PM
To: georss at lists.eogeo.org
Subject: Re: [georss] Time and Space

One of the major concepts of GeoRSS is to be less geo-centric, so my  
initial reaction is to advise attaching the time period to your more  
general information nugget instead of the geometry, but I'm not sure  
if you are working with an RSS feed in the first place.

Your requirement gets at the specification of start time and  
expiration of information. Most flavors of RSS have some sort of  
'publication' date, but even that doesn't have the semantics of what  
you're talking about, so I agree your requirement isn't fulfilled  
somewhere else.

So if you're working with Atom+GeoRSS, the most universal approach  
would be to extend the Atom item with more specifics about time.
---
Raj


On Feb 12, 2007, at 8:40 AM, Knoth, Brian D. wrote:

> Hi,
>
> I'm new to this mailing list, yet have been advocate of RSS and
geoRSS
> on some internal projects for a while. I do have a few concerns with
> regard to real practical acceptance of geoRSS, yet, I understand the
> need to try and balance simplicity and expressiveness. As such, we
are
> attempting to utilize GML geoRSS, however, we have needed to extend  
> the
> GML geoRSS with the ability identify time as well as space.
>
> I wanted to just send out our approach to doing this to get comments
> from anyone else who might be interested in this on the mailing list.
> Simply put, we have added a GML TimePeriod to each of the geoRSS
nodes
> along with the spatial representation. Here is an example:
>
> <georss:where>
> 	<gml:TimePeriod>
>    		<gml:begin>2006-06-17T09:55:00Z</gml:begin>
> 		<gml:end>2006-06-17T10:30:00Z</gml:end>
> 	</gml:TimePeriod>
> 	<gml:Point>
> 		<gml:pos>37.65356495497155 -114.5048399056895</gml:pos>
> 	</gml:Point>
> </georss:where>
>
> All comments would be appreciated.
>
> Regards,
> brian
> _______________________________________________
> georss mailing list
> georss at lists.eogeo.org
> http://lists.eogeo.org/mailman/listinfo/georss

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