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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.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.
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 *************************************************************
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