Re: netCDF coordinate system question

Steve Hankin (hankin@rogue.pmel.noaa.gov)
Fri, 16 Jun 1995 12:03:56 -0700 (PDT) 

Hi Jason,

We frequently use netCDF for data sets of this descriptiuon.  There are no 
netCDF structures (that I am aware of) to explicitly encode the grid you 
describe.  However, it is straightforward to include your vertical 
coordinate information in a separate netCDF variable -- either as the actual 
vertical positions or the vertical layer thickness, whichever suits your 
applications better.  Then it becomes the responsibility of the 
application to use the vertical coordinate information appropriately.
 
(Commonly that means using the vertical coordinate information to 
pull iso-surfaces (constant depth or height) from your data.  If you 
don't have a tool that does this one possibility is the Ferret program.  
email me off-line if you'd like further description.)

	cheers - steve


On Thu, 15 Jun 1995, Jason Levit wrote:

>   Hi everyone,
> 
>   I'm trying to define a coordinate system in a netCDF data file
> which includes a stretched vertical grid **with terrain**.  This
> means that the vertical coordinate is not uniform over the entire
> domain *or* in a 2-D x-y plane.  In other words, a point at 
> 3,5,18 will have a physical height of 4.0, but a point at
> 6,12,18 will have a physical height of 12.0.  If I can use the
> physical height to define the 3-D coordinate system, that would
> be great, but I have yet to find a way to define this coordinate
> system in netCDF.  Does anyone have experience in defining a
> stretched vertical grid w/terrain in a netCDF file?  If you do,
> please let me know!  Thanks very much for your help!!
> 
>   Jason Levit
> 
> --------------------------------------------------------------------------------
> Jason John Levit, N9MLA                    Undergraduate Research,             
> University of Oklahoma          Center for Analysis and Prediction of Storms  
> School of Meteorology                  jlevit@tornado.gcn.uoknor.edu          
> PH:405/325-5366                      www: http://tornado.gcn.uoknor.edu/
>