Hi, Independently of our recent discussion of netCDF coordinate conventions and the merits of "multidimensional coordinate variables" vs. "referential attributes", Jonathan Gregory, Bob Drach and Simon Tett have just published a draft of "Proposed netCDF conventions for climate data", available for review at http://www-pcmdi.llnl.gov/drach/netCDF.html or in PostScript form from http://www-pcmdi.llnl.gov/drach/netCDF.ps.Z This document extends the COARDS conventions, and in particular provides a good specification for the meaning and use of multidimensional coordinate variables. I've created a link to the document from the netCDF Conventions page at http://www.unidata.ucar.edu/software/netcdf/conventions.html The authors have asked for feedback: Our principal interest in proposing this convention is to facilitate the exchange of data among climate centres. NetCDF offers an appropriate format for this purpose, and these conventions aim to standardise the representation of metadata sufficiently that data from different sources can be easily compared. We recognise that there are limits to what a standard can practically cover; we restrict ourselves to issues which we believe to be of common and frequent concern in the design of climate metadata. Our convention is mostly compatible with the existing COARDS convention, but we have extended the scope and detail. We are aware that some climate centres are already using netCDF as their archive format. We would be very interested to have comments from them, for instance on how our suggestions differ from what they do, and on what lessons they have learned from experience. We would welcome feedback from anyone on these conventions, such as on what has been omitted, what could be improved, and how we should carry this proposal forward. The exercise will only be useful if it has the support of a number of climate centres, of course. One application which will adopt this standard is the LATS software distributed by the Program for Climate Model Diagnosis and Intercomparison (PCMDI), sponsor of AMIP II. LATS will have an option to generate netCDF files which conform to this standard. Our second interest in developing this standard is its relation to a logical model of the data and metadata. Describing how the data should be stored in netCDF inevitably involves considering how it is organised logically. We hope to be make a proposal for a language-independent data model, which could be implemented in various programming languages as a method of handling data either in memory or in files. If this were done, it would offer a way of making analysis programs more easily portable. Please send any comments you may have on the proposed standard or any of the above to any of us. Feel free to circulate it further if you know others who would be interested. Thank you. Jonathan Gregory jmgregory@meto.gov.uk Bob Drach drach@llnl.gov Simon Tett sfbtett@meto.gov.uk --Russ _____________________________________________________________________ Russ Rew UCAR Unidata Program russ@unidata.ucar.edu http://www.unidata.ucar.edu