[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

20050204: extracting dBZ values from a point in space from NIDS files



Leigh,

I wrote $NAWIPS/unidata/programs/gdradr (and nex2gini/nex2img) to
composite radar images, so the routines there would be the easiest
location to make a program that gets a radar, navigates it, and then
outputs the single pixel value. Gdradr just happens to do it for
a number or radars, and all the pixels. You could have a single
radar in STNFIL though. I haven't tested a single point GRDAREA.

Garp's method of loading in the raster and keeping that
in memory for display on mouse over isn't that different, but the
combination of the GN device driver is built in to gdradr.

Steve Chiswell
Unidata User Support




>From: Leigh Orf <address@hidden>
>Organization: Department of Tesselating Kumquats
>Keywords: 200502050315.j153FFv2013751

>
>Hello,
>
>I am involved in a research project where the values of reflectivity
>at a single point (pixel) in space are to be tracked over time (we
>are trying to correlate measured lake effect snow amounts with
>reflectivity). What I would like to do, if there is not already
>a way to do it with GEMPAK, is write a program (C preferably, or
>FORTRAN) which uses the existing gempak libraries to open a NIDS file
>(e.g. N0R_20050203_2320) and, given lat/lon (or any navigation) data,
>spit back a dBZ value.
>
>I have downloaded the latest gempak source code and looked around for
>a couple hours, found some promising areas, but have pretty much come
>up blank - there is a lot of code in there. I spent a lot of time
>in GEMPAK5.7.4/gempak/source/driver/active/gn/crnids.c which seemed
>promising but didn't get very far.
>
>Seeing as GARP brings up radar data and tracks lat/lon and pixel dBZ
>values with the mouse, I figure the capability is in there. Since I will
>be operating at a single point in space on tens or even hundreds of
>NIDS files a simple program called in a script where it's looping over
>NIDS filenames seems to me to be the way to go. Any pointers for which
>subroutines to call and the right way to link with the libraries to
>compile something useful?
>
>Thanks,
>
>Leigh
>
>--
>Leigh Orf
>KG4ULP
>Assistant Professor of Atmospheric Sciences
>Department of Geography
>Central Michigan University
>Mount Pleasant, MI 48859
>(989)774-1923
>
--
NOTE: All email exchanges with Unidata User Support are recorded in the
Unidata inquiry tracking system and then made publicly available
through the web.  If you do not want to have your interactions made
available in this way, you must let us know in each email you send to us.