[thredds] coordinates = "time lat lon lat lon"

• To: thredds@xxxxxxxxxxxxxxxx
• Subject: [thredds] coordinates = "time lat lon lat lon"
• From: Jay Alder <jay.alder@xxxxxxxxxxxxxxxxxxx>
• Date: Thu, 4 Oct 2012 14:38:42 -0700

Hello all, I recently noticed some strange behavior with the "Add Lat/Lon 
variables" in the NCSS if the data is already in lat/long space. We have a web 
application that calls the NCSS service from a mapping interface and a while 
back I forced the REST call to include addLatLon=true. Most of our data is 
projected so it was handy to have the lat/lons written into the netcdf file. 
However, one of our users noticed that datasets which were already in lat/lon 
have variable metadata with coordinates = "time lat lon lat lon" rather than 
the expected coordinates = "time lat lon". It seems a bit redundant to include 
addLatLon=true when the coordinates are already in lat/lon, but its hard coded 
into our web application. I did some testing with the thredds html interface 
and found if I include addLatLon=true variables will have coordinates = "time 
lat lon lat lon", whereas if I omit addLatLon=true you get the expected 
coordinates = "time lat lon".

So the question is why does including the lat/lon variables change the 
coordinate metadata on a variable and does it matter to netcdf viewing 
applications? The data appears to load into ArcMap either way. For reference, 
I'm using TDS 4.2.6 so this quirk may already have been fixed.

Thanks


Jay Alder
US Geological Survey
Oregon State University
104 COAS Admin Building
Office Burt Hall 166
http://ceoas.oregonstate.edu/profile/alder/