NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
Current content can be found at unidata.ucar.edu.

To learn about what's going on, see About the Archive Site.

Re: [netcdf-java] Common Data Model plans

Hi John,
While presenting our Time Series Data Server poster (http://sourceforge.net/projects/tsds/files/TSDS_poster_nobg.pdf/download) at AGU, for example, I talked with some people who live in a CDF centric environment. They have their tools that are likewise tightly coupled to the CDF APIs. It is not realistic for them to refactor their system and retool their clients to use the NetCDF libraries, but it may be reasonable for them to abstract out a CDM interface and break the coupling between "client" code and "server" code. Once that happens, any code that writes to the CDM interface can interoperate.
I agree that providing the ideal CDM API is a grand idea and bound to be fraught with pesky reality. So, I guess my question is, is such an API part of the vision for the CDM? I take it the answer is that it is desirable but not immediately practical, or funded. 

Thanks,
Doug

On 3/27/10 12:03 PM, John Caron wrote:

Hi Doug:

While there are some simple UML descriptions of the CDM, the real
work and thought is in the netcdf-Java library and API. It evolves
from the ground up, as we deal with more datasets and data types.

In an ideal world, we probably would develop an interface that
corresponds to a "pure" CDM description. In the real world, theres
not enough resources or motivation to do so. Also, its still evolves,
esp at the feature type APIs, and i dont think its time yet to cast
that in stone.

Can you describe some use-case in some detail? Why would a group
"never adopt NetCDF-Java" ? What is the issue there that could be
solved by a lightweight API ?

John



Doug Lindholm wrote:

I still intend to focus on Java, but I want to be able to plug in
a light-weight alternative to NetCDF-Java. I have a system with a
data model implementation that is consistent with the CDM. Instead
of writing an IOSP or subclassing NetcdfFile and taking on all of
NetCDF's dependencies, I'd like to have a Java Interface that my
data model could implement. All "client" code would then write to
that interface. NetCDF and other implementations of that same
interface would then be usable by that same client.

I work with groups that will never adopt NetCDF-Java but they
might implement a simple set of Java Interfaces with their data
model. This would lower a lot of barriers to interoperability. Is
the CDM moving in this direction or is the plan to expose all other
data via the NetCDF-Java API?

Thanks, Doug

On 3/26/10 2:15 PM, Richard Signell wrote:

Doug,


What is the state of the Common Data Model
(http://www.unidata.ucar.edu/software/netcdf-java/CDM/)? Is
there a complete definition of the model. The UML on that page
communicates the idea well, but I'd like to see an interface
that I could program to. Right now, I am uncomfortably tightly
coupled to the NetCDF Java implementation.


What other language are you planning to be coupled to?

Just thought others in the community might be curious besides
me.

-Rich



_______________________________________________ netcdf-java mailing
list netcdf-java@xxxxxxxxxxxxxxxx For list information or to
unsubscribe, visit: http://www.unidata.ucar.edu/mailing_lists/
  • 2010 messages navigation, sorted by:
    1. Thread
    2. Subject
    3. Author
    4. Date
    5. ↑ Table Of Contents
  • Search the netcdf-java archives: