sfmap, FILTER, and station priority

Hello,

It appears that a station's priority, ispri in GEMPAK-5.6 sf_qstn and
the like, is not used in the FILTER algorithm for sfmap and other
programs.  Am I right?  If so, I would like to tackle the problem of
making them use it so a station with a lower ispri (higher priority)
gets chosen before a station with a bigger ispri (lower priority).
This is the way we use WXP to effectively filter a very dense network
of observations in our area.  Can you point me to the appropriate
GEMPAK routines?

Ideally, a single use of sfmap with AREA=dset and FILTER=1 would do
what I want; however, for my chosen area, stations that we really want
to see, such as KSEA, get omitted in favor of lower priority ones, such
as KBFI when FILTER is used exclusively.  Currently, I have to go
through several iterations of sfmap in order to get it to do what I
want, as you can see from this script (note that I use the country
field to specify observation type in our files):

#!/bin/csh
sfmap <<EOF > /dev/null
# DEVICE   = gf | testsfmap.gif | 1024;768
 GAREA    = 44.75;-125;50.8;-116.75
 SATFIL   = $GARPHOME/map/areas/nw_namerica
 LUTFIL   = topo_ltgray2.tbl
 RADFIL   =  
 DATTIM   = 0
 SFFILE   = $GEMDATA/surface/latest/uw.gem
 MAP      = 1/1/1
 LATLON   = 0
 TITLE    = 4/-2/0Z Standard Obs
 PANEL    = 0
 PROJ     = SAT
 FILTER   = no
 STNPLT   =  
 CLRBAR   = 

 CLEAR    = y
 AREA     = @sa:c/@bf:c/@cm:c
 SFPARM   = skyc:.75;tmpf;wsym:.75;smsl;blnk;dwpf;spri<4;brbk:1:1;mark:2
 COLORS   = 32;2;7;0;4;0;32
 TEXT     = small/3//hw
run

 CLEAR = no
 MAP = 0
 title    = 0

 SFPARM   = ;;;;;;stid;spri<4
 colors   = 32;0
 text     = tiny/1//hw
 run

 area = @uw:c
 SFPARM   = ;;;;brbk:1:1;mark:2
 COLORS   = 29;19
 text     = 1/3//hw
 run

 area = @rw:c/@av:c/@ap:c/@am:c/@dt:c/@br:c/@gs:c
 SFPARM   = skyc:.75;blnk;wsym:.75;blnk;blnk;blnk;stid;brbk:1:1;mark:2:.7
 COLORS   = 8;8;32;8
 text     = tiny/1//hw
 filter   = 1
 run

 area=@sa:c
 SFPARM   = skyc:.75;blnk;wsym:.75;blnk;blnk;blnk;spri>5;brbk:1:1;mark:2
 COLORS   = 32;7;0;32
 text     = small/3//hw
 filter   = 1
 run

exit
EOF
gpcolor <<EOF
 colors = 101=white
 run

exit
EOF
# gpend


Thanks for any help.


David
-- 

David Ovens             e-mail: address@hidden
(206) 685-8108          plan: Real-time MM5 forecasting for Pacific Northwest
Research Meteorologist
Dept of Atmospheric Sciences, Box 351640
University of Washington 
Seattle, WA  98195