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Re: ISSUE-19 (point-encoding): How should we represent points? [Core FPWD]

From: Raj Singh <rsingh@opengeospatial.org>
Date: Mon, 13 Jun 2011 16:50:19 -0400
Cc: Jens de Smit <jens@layar.com>, public-poiwg@w3.org
Message-Id: <45EBBAE8-42E4-49A5-B725-FE179D67CBC0@opengeospatial.org>
To: Thomas Wrobel <darkflame@gmail.com>
I think we still do have the requirement that each POI specifies its own CRS with a default of WGS84.

Some of your points refer to moving objects, which I think we have agreed are a slightly different type of POI than we will fully describe in the Core. So that we do a better job of sticking to Core discussion and finishing that -- while not losing the voices around the extensions of interest -- I've created a wiki page to capture this information:
http://www.w3.org/2010/POI/wiki/Extensions

---
Raj
The OGC: Making location count...
http://www.opengeospatial.org/contact


On Jun 12, at 2:03 PM, Thomas Wrobel wrote:

> Depending on accuracy, calculating between lat/lon and meters can be
> massively, massively, complex. You get into such factors as the real
> shape of the earth - its not a simple bit of trig sadly.
> Of course these are all "solved problems", but if possible its nice if
> a client doesn't have to do them. (or, rather, as little as possible -
> working out a position in meters for lat/long, then displacements from
> that is less cpu then working out a large batch of conversions).
> Neither is insurmountable, however.
> 
> From my perspective the most usefull scenario for relative
> co-ordinates is simply with stuff that can move - it would be nice if
> only one gps location change has to be passed to the client, rather
> then everything attached as well.
> 
> I'm also still favouring the idea that each POI should specify its own
> reference system ( WGS84 default), and if it links to another POI
> ("relative too" or something), then it positions its own reference
> system (if not WGS84) relative to that one. This should make any
> inter-POI positioning no more verbose then anything else.
> This wouldn't solve multiple co-ordinate systems within the same
> POI....but I'm not sure how much that will be used in the AR Field.
> 
> -Thomas
> 
> On 10 June 2011 17:26, Raj Singh <rsingh@opengeospatial.org> wrote:
>> Jens, I think you probably mean to support both point formats, and only use the GeoRSS GML format (more brevity) for lines and polygons? I can live with that.
>> 
>> ---
>> Raj
>> The OGC: Making location count...
>> http://www.opengeospatial.org/contact
>> 
>> 
>> On Jun 10, at 9:58 AM, Jens de Smit wrote:
>> 
>>> I've heard (on the list and on the call yesterday) arguments for both
>>> the short, space separated form and the long, individual key form.
>>> Brevity and conformance to GML/GeoRSS are arguments for the short
>>> form, ease of lookups/XSLT and explicit naming of lat/lon/alt for the
>>> latter.
>>> 
>>> Saying "let's use both" obviously places the burden on the
>>> implementors... but I think this is still manageable, so I'd like to
>>> see both.
>> 
>> 
>> 
Received on Monday, 13 June 2011 20:50:54 UTC

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