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[IDV #KWE-346293]: degrees_east > 180 plots off map!

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  • Subject: [IDV #KWE-346293]: degrees_east > 180 plots off map!
  • Date: Sun, 08 Feb 2009 13:25:38 -0700
Hi Rich-

I've finally gotten back to this (only taken a year).  If I
load in the test.nc file that the peru.ncml points to, it
looks like the lat/lons have been changed.  Is that true?
If so, do you have a file that exhibits the initial behavior?

Thanks.

Don
> > On Tue, Apr 15, 2008 at 5:30 PM, Unidata IDV Support
> > <address@hidden> wrote:
> >
> > >  It's really that the map lines go from -180 to 180 and the data
> > >  goes from 0-360.  Depending on the projection, one will not
> > >  line up.
> >
> > Ah, okay.
> 
> Let me explain that a bit more.  The map projection from the
> data is based on the range of the longitude values in the data.
> In your case, you have values > 180.  The  map lines are in
> -180 to 180.  So, the map projection is going to be to the
> right of the map lines:
> 
> -180       180  200+(your area)
> 
> map        data
> 
> However, when you change the data to be in the -180 to 180 range,
> then both are within the same bounds.
> 
> (not sure if that clears it up or makes it more  confusing).
> 
> > >
> > >  > If would be nice if IDV did this so I didn't have to!
> > >
> > >  That would be nice. ;-)
> > >
> > >  > http://stellwagen.er.usgs.gov/models/share/peru.ncml
> > >
> > >  That dataset only goes to about -160.  Is that the correct
> > >  link?  I'm not sure I'm understanding the problem you are seeing
> > >  with this example.
> >
> > If you delete the line in the NcML where I overwrote the Longitude
> > values you will see the problem.
> 
> I've put a check in there to see if the bounds of the map
> projection fall within 0-360 or -180 to 180.  Based on that
> I normalize all longitudes to fit in that range.  I've got
> a lot of testing to do, but this might just work.  Thanks
> for the suggestion.
> 
> Don
> 


Ticket Details
===================
Ticket ID: KWE-346293
Department: Support IDV
Priority: Normal
Status: Open