Re: Deployed: Bug fixes to NetCDF Java API 4.1.20100227.0121

On 3/29/2010 11:48 AM, Tom Margolis wrote:
> Hi John,
>
> I did indeed think about the fact that a monotonic CoordinateAxis1D is
> assumed throughout your code, but I'm not familiar enough with the code
> to uncover all the tangential effects of supporting non-monotonic
> longitude axes, nor do I have unit tests that test all your code.   I
> ran all the tests I could from my side.  My assumption was that you
> would run your test suites using the new CoordinateAxis1D to uncover
> these tangential effects.  If you don't have unit tests that would do
> so, maybe that's something we could work on.
>    

we never have enough unit tests, so we just try to add them when we can.

>    
> > Its possible that a better strategy is to have CoordinateAxis1D
> >      
> monoticize its values
> I think this would simply shift the problem.  The goal is to support
> both [0 to 360] *and* [-180 to 180] longitude scales; in other words,
> the CoordinateAxis1D should be able to interpret -20 and 340 as the same
> longitude value.  If CoordinateAxis1D monoticizes its values (i.e.
> converts them to a [0 to 360] scale), then it won't support [-180 to
> 180] values, and we're back to square one.
>    

i think you misunderstand. the idea is not to support normalized values, 
only monotic coordinates. so a lon range that goes from 160 to -160 
would be changed to go from 160 to 200.

the reason this can work is there is a distinction between Lat/Lon 
Points and coordinates. there is always a transformation: latlon <--> 
coord. In this case, the coords would be longitudes between 160 and 200, 
so a lat/lon value of -170 would get converted to coordinate of 190. If 
you look at LatlonProjection, you may get the idea better.

>    
> > These appear to be the same as what you previously sent?
> >      
> Acutally, the compareToLonRange(..) method called in the latest
> GridCoordSys class is different than the one I had previously sent, so
> it's probably safest just to adopt the new GridCoordSys class.
>
>    
> > It would be helpful to me in reviewing your fixes if you would
> >      
> summarize the problem, as well as the fix
> Sorry - I thought I had summarized the problem in previous emails, but
> it's probably best if I summarize the summaries (!) in one email.  And I
> can certainly send you unit tests; do you need them for these fixes or
> just for subsequent fixes?
>    

well, maybe we should try it for these problems and see how it works 
out, it may clarify how to do this in the future.