Meeting: 13 May 2003

[Eliot Christian <echristi@usgs.gov>]

GIS SC Meeting Notes of 13 May 2003

The meeting was conducted via conference call. The Group discussed the 
document "GML/XML schema for select GML geometry".

It was agreed that at this time GML was much more than would be required 
for simple CAP messages. The GIS SC recommends refining what is presently 
in the CAP schema. We will develop/refine the CAP data dictionary and 
develop elements that are compatible with common practice in the GIS community.

Further: That we would require that geographic positions in the message 
would be in WGS 84 (equivalent to EPSG codes 4326 (2 dimensions) in decimal 
degrees (un-projected) "http://164.214.2.59/GandG/tr8350_2.html" The US DoD 
and NATO have standardized using WGS 84 in exchanging geographic position 
information to avoid miscommunication.

We would use local Mean Sea Level as the vertical datum with values in 
feet. (Elevation in feet is the standard UOM for aeronautical navigation)

CAP users would convert to WGS 84 (if not already using it) to produce the 
message and message recipients would convert to coordinate 
system/projections as needed.