RE: [emergency] RE: Notes form last GIS SC meeting

[David Danko <DDanko@esri.com>]

There are three ways of doing this - from the very beginning we've followed
the KISS principle - simple and unambiguous communication.

1. allow people to use any coordinate reference system and make them
identify the one they used. The problem is not everyone receiving the
message will be using a GIS and may not be able to handle that particular
CRS. If they knew ahead of time what CRS will always be used they will be
prepared for it.
 
Or
2. (as Carl mentions below -Recommended XML Encoding of
CRS Definitions) have the people use whatever they want and include the
whole description of the CRS - Then there is no miscommunication about the
definition of all the parameters in the CRS, trouble is, half the people
wouldn't know what to do with them.

Or

3.  Make everyone use the same coordinate reference system - so there is no
mis-communication - users would know what to expect, that's what we've done
in this version of CAP. That's what the US military does/is trying to do -
after learning the hard way.


Dave




 

-----Original Message-----
From: Carl Reed
To: R. Allen Wyke
Cc: emergency TC lists Oasis
Sent: 3/23/04 11:47 AM
Subject: Re: [emergency] RE: Notes form last GIS SC meeting

Allen -
 
The key point is that the GIS SC recommends that the use of WGS 84 is
fine for CAP 1.0.
 
Moving forward, it is my personal feeling - and I know that others share
the same feeling - that CAP version 1.x will need to be enhanced to use
what you termed a coding identifier. One possible route (and the one I
would favor) would be to use the work of the OGC on Coordinate Reference
Systems (CRS). The OGC CRS abstract and encoding specifications are
fully grounded in and supplements the ISO TC 211 document ISO 19111:
Geographic Information - Spatial Referencing by Coordinates. The basic
premise is that we use a standard "model" for expressing a CRS and that
this model is "well known".