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[GEMPAK #NIO-589154]: Pulling data from points

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  • Subject: [GEMPAK #NIO-589154]: Pulling data from points
  • Date: Wed, 25 Jan 2006 13:06:29 -0700
>I am interested in overlaying IR satellite imagery with lightning
>location points. I would then like to pull the cloud temperatures at
>those points to use in some statistical analysis. Is this possible in
>GEMPAK, if so could you point me to a link?

Phil,

NMAP2 and GARP have methods for reading out mouse values for images,
but for programatic use, you would simply need a program wrapper to
call $GEMPAK/source/gplt/satellite/gsatpx.f
(which is what the $GEMPAK/source/gemlib/im/imgpix.f routine is doing to
get a cloud height from an IR image as called by the cloud height routine
in NMAP2).

As an example, if you build the source distribution, you can build the testim 
program with:
cd $GEMPAK/source/gemlib/im
make tlink

Then the testim program would be a simple lat, lon readout program such as:
> testim
  1 = IM_SIMG                 2 = IM_ISUB 
  3 = IM_DROP                 4 = IM_LUTF 
  5 = IM_QSIZ                 6 = IM_GPIX 
  7 = IM_BTOT                 8 = IM_TTOB 
  9 = IM_GTMP                10 = GG_SDEV 
 11 = GG_MAP                 12 = GG_LTLN 
 13 = GG_STTL                14 =         
 15 = IM_QTIM                16 = IM_QLUT 
 17 =                        18 = IM_QCHN 
 20 = GSBRGB                 21 = GQCLRS  
 22 = GCLEAR 
 23 = GSROAM                 24 = GROAM  
 30 = DUMP COMMON 
Select a subroutine number or type EXIT:6
 Enter IMGFIL
$SAT/GOES-10/4km/IR/IR_20051004_2000
 Enter GAREA
dset
 Enter GEMPAK time
051004/2000
 Enter RLAT, RLON
20.00, -157.00
 Enter maximum search distance
1000000
 Enter stndard sounding flag
f
 Enter moist-adiabatic cloud flag
t
 Enter pixel area, 0 -> single pixel, 5 -> 11 x 11 area 
0
 Enter pixel mode
0
 [SN 5]  Stable sounding.
 IRET =            5
 [IM 5]
 IPIX =          107
 TMPK =    276.5000



Ultimately, it sounds like you need to take the lightning locations from a 
gempak
surface file (is your lightning source the NLDN data which is decoded into 
GEMPAK-
or a different source?), and specify an IR image , and then put the cloud 
temperature into
that surface file. Due to the proximaty of the AMS meeting next week and
other time commitments, if you would like some development/help it will be 
later in
February before I could put something together.

Steve Chiswell
Unidata user Support

Ticket Details
===================
Ticket ID: NIO-589154
Department: Support GEMPAK
Priority: High
Status: Closed