Hello Rich I think that using the WKT representation for vertical datum definitions is a good approach
As you have indicated, it is to be supported in CF 1.7 and provides a controlled terminology set for this purpose. There is an example using the OS Newlyn datum in the draft spec which fits quite nicely. I'd rather see us adopting WKT for complex issues like this than creating a syntax for encoding CF grid_mapping attributes, there's a lot of prior art we can benefit from. For example WKT enables me to specify more than just the EPSG code, which is useful as not all datum instances are provided by EPSG mark ________________________________________ From: CF-metadata [[email protected]] on behalf of Signell, Richard [[email protected]] Sent: 04 February 2014 11:47 To: CF metadata Subject: [CF-metadata] Vertical datums (again) CF folks, On a telecon yesterday with a coastal inundation modeling group, one of the PIs asked me how to handle vertical datums in NetCDF -- specifically where to specify that the model bathymetry and water levels were were relative to NAVD88. I wasn't sure how to reply. Was there any resolution to the 2nd half of this question asked back in 2011? http://mailman.cgd.ucar.edu/pipermail/cf-metadata/2011/054483.html I looked at the draft 1.7 spec, and the only vertical datum reference info I found was the ability to specify VERT_DATUM in the new CRS well-known-text (WKT) section: http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.7-draft1/ch05s06.html#idp5644304 Is this how we should specify the vertical datum in CF, using VERT_DATUM in WKT? Thanks, Rich -- Dr. Richard P. Signell (508) 457-2229 USGS, 384 Woods Hole Rd. Woods Hole, MA 02543-1598 _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
