Yep - the 2.3 release fixed the isosurfacing problems we were seeing.
Thanks!!
-kevin.
----- Original Message -----
From: Don Murray <dmurray@xxxxxxxxxxxxxxxx>
Date: Friday, August 17, 2007 2:05 pm
Subject: Re: [idvusers] Isosurface Interpolation
> Hi Kevin-
>
> Kevin Manross wrote:
> > Thanks for the reply, Don and Stu!
> >
> > Regarding the "discontinuities", I'll try to get an image for you
> - I'll
> > describe them in the meantime.
>
> That would be good.
>
> > There are several consistent areas in the vertical where we are
> seeing a
> > quasi-stair-step in the isosurface. Your explanation of
> normalizing the
> > radial azimuths may explain this. I'll install and test the 2.3
> release
> > and see if this helps any.
>
> This sounds like the bug we fixed in the 2.3 release. Let me know if
> you still see the problem.
>
> > Is the normalizing of azimuths required, or is it intended for
> better
> > efficiency? The reason I ask ties into my attempt to get the
> NSSL
> > netCDF output into the IDV and whether I need to do some of this
> > normalizing in the netCDF files or whether the IDV will take care
> of
> > that for me.
>
> If you write an netCDF IOSP (which the other support question referred
> to), the IDV will take care of that for you.
>
> > While on this subject of the NSSL netCDF output, the way we have
> out
> > data is Product/ElevationAngle/datafile.netcdf. So for
> Reflectivity, it
> > would look like:
> >
> > Reflectivity/00.50/20070620-040217.netcdf.gz
> > Reflectivity/01.45/20070620-040255.netcdf.gz
> > Reflectivity/02.40/20070620-040330.netcdf.gz
> > Reflectivity/03.35/20070620-040352.netcdf.gz
> > Reflectivity/04.30/20070620-040412.netcdf.gz
> > Reflectivity/05.25/20070620-040431.netcdf.gz
> > Reflectivity/06.20/20070620-040451.netcdf.gz
> > Reflectivity/07.50/20070620-040511.netcdf.gz
> > Reflectivity/08.70/20070620-040526.netcdf.gz
> > Reflectivity/10.00/20070620-040540.netcdf.gz
> > Reflectivity/12.00/20070620-040554.netcdf.gz
> > Reflectivity/14.00/20070620-040609.netcdf.gz
> > Reflectivity/16.70/20070620-040623.netcdf.gz
> > Reflectivity/19.50/20070620-040637.netcdf.gz
>
> We'd have to do some work to aggregate these.
>
> >
> > With regard to rendering a volume scan, can I give the IDV the
> top level
> > directory and have it construct the volume from the subdirectory
> > structure, or will I need to dump all the elevation angle data
> into one
> > file?
>
> Right now, you would have to dump them in one file, or we'd have
> to figure out how to aggregate them. The first issue to attack
> is how to get the NSSL format into the netCDF Radial Data structure
> that the IDV uses. I'll contact you off the list to discuss that
> further.
>
> Don
>
> > Don Murray wrote:
> >> Hi Kevin-
> >>
> >> Kevin L. Manross wrote:
> >>> I have a couple questions regarding isosurfacing in the IDV.
> We are
> >>> using it to look at isosurfaces of radar reflectivity and we're
> >>> noticing several discontinuities in the vertical when viewing
> Level
> >>> II data. Can anyone tell me what type of interpolation is
> being used
> >>> for the isosurfacing? Is this technique something that can be
> >>> modified via the IDV? If not, is it possible for a user (me)
> to
> >>> write some sort of plugin to change this interpolation?
> >>
> >> When you say discontinuities, what do you mean? We just fixed a
> bug>> in the 2.2 release where some of the levels were shifted and
> it made
> >> for some weird isosurfaces. Try out the 2.3 release and see if
> that>> works better for you.
> >>
> >> Since radar sweeps in a volume do not have a standard pattern
> for the
> >> scans (e.g. each sweep starts at a different azimuth and the
> number>> of azimuths may vary by sweep), we normalize the sweeps to
> a 0-360 set
> >> of azimuths, putting the closest radial to each azimuth in for
> the data.
> >> This gives us a "rectified" domain which makes the isosurface
> alogrithm>> work better (but maybe not perfect). As to the
> details, it uses the
> >> standard VisAD algorithm, the details of which I'm not sure of.
> But>> that could be answered by someone on the VisAD list.
> >>
> >>> Also, I've played around a little with the vertical scaling
> widget
> >>> and it doesn't seem to have any appreciable effect. (I changed
> my
> >>> vertical scale from 16000m to 20000m.) When viewing a radar
> domain,
> >>> it would be great to have the vertical scale of a storm more
> >>> proportional to its horizontal scale.
> >>
> >> Stu's response is how I do it - use the Range and Bearing tool to
> >> calculate the width of the box, set the vertical aspect to 1 and
> >> set the vertical range accordingly.
> >>
> >> Don
> >> *************************************************************
> >> Don Murray UCAR Unidata Program
> >> dmurray@xxxxxxxxxxxxxxxx P.O. Box 3000
> >> (303) 497-8628 Boulder, CO 80307
> >> http://www.unidata.ucar.edu/staff/donm
> >> *************************************************************
> >>
> >>
> >
>
> --
> *************************************************************
> Don Murray UCAR Unidata Program
> dmurray@xxxxxxxxxxxxxxxx P.O. Box 3000
> (303) 497-8628 Boulder, CO 80307
> http://www.unidata.ucar.edu/staff/donm
> *************************************************************
>
>
>