20040929: NTP plot question

Dana,

I'm assuming you are gridding the NTP with gdradr.

The Level III NTP product provides data at 16 discrete
data bins. The data bins used by the radar depend on the 
range of data.

The lowest data bin is ND (no data), and the second lowest is
generally >0.0. Above that, the bins are range dependent,
some example scale are (using TLX and AMX today):
ND              ND
>0.0            >0.0
.3              .5
.6              1.0
1.0             1.5
1.5             2.0
2.0             2.5
2.5             4.0
3.0             6.0
4.0             8.0
5.0             10.0
6.0             12.0
8.0             14.0
10.0            16.0
12.0            18.0
15.0            20.0

In this first case above you whould see data values of .3 explicitly
(eg less than your .5), but in the second case, you won'tn'
have any contours between 0 and .5. Also in the second case, you
loase the distinction between 2.5 and 3.0 as the first .

Note that the grid created by gdradr will be floating point values
from possibly multiple radars (in different ranges) using the greatest
value reported at a grid point (where the bins ranges  may not be the same).

One thing you may want to use in gdradr is the NDVAL field to explicitly
set the ND=-9999 so that if you want to see the >0.0
values as zero, you can fill starting at 0, instead of your .01.

If you have the NTP level III files that were used to create the
grid displayed in your gif, look at the data scale/ranges and see
if that provides your answer. If still a mystery, can you provide
the source GDRADR settings and your level III files so that I
can reproduce your grid?

Steve Chiswell
Unidata User Support




>From: Dana Price <address@hidden>
>Organization: UCAR/Unidata
>Keywords: 200409291429.i8TET6HP023574

>Hi,
>
>I'm plotting storm precip with gdplot2, but some of the colors that I 
>define for certain intervals are never used.  Example is at
>http://www.wx.rutgers.edu/rad/data/nexrad/DIX/NXTP/0409291333_NXTP.gif
>
>We're not seeing either of the colors that define precip < .5 inches, 
>save for when they outline an area upwards of .5.  The same goes for the 
>green between .75-1.0, the yellow between 2.5-3, and the purple between 
>7-8.  Am I doing something wrong?  The gdplot2 and gdradr scripts follow:
>
>gdplot2 <<EOF
>device   = gif|/data/wx/rad/gifs/nexrad/DIX/NXTP/$fdesc$fext|600;600
>gdfile   = nj-dix-ntp.gem
>!proj     = lcc/25;-103;60/3;3;0;0
>proj     = mer
>!garea    = 37.85;-76.80;41.8;-72.0
>garea    = 37.85;-77.2;41.8;-72.2
>map      = 2
>clear    = n
>gdattim  = LAST
>text     = 1/1/1
>TITLE    = 1/-1/~ Rutgers Weather Center 1km Storm Total Precip
>GDPFUN   = ntp
>GLEVEL   = 0
>GVCORD   = none
>TYPE     = F
>!FINT     = 10;15;20;25;30;35;40;45;50;55;60;65;70;75
>!FINT     = 0;.25;.5;.75;1;1.25;1.5;1.75;2;3;4;5;6;10
>FINT     = .01;.1;.5;.75;1;1.5;2;2.5;3;4;5;6;7;8;9
>!FLINE   = 0;21-23;20;18;17;15-7
>FLINE    = 00;27;25;24;21;22;23;20;19;17;02;15;14;07;28;31
>CLRBAR   = 1/V/LL/0.001;0.15/0.82;0.010/1|1/1/1
>PANEL    = 0
>SKIP     = 0
>SCALE    = 0
>CONTUR   = 0
>HILO     = 
>LATLON   = 0
>STNPLT   = 
>SATFIL   = 
>RADFIL   =
>LUTFIL   = 
>STREAM   = 
>POSN     = 0
>COLORS   = 1
>MARKER   = 0
>GRDLBL   = 0
>FILTER   = YES
>
>r
>
>CLEAR = n
>TITLE = 0
>\$mapfil = hicnus.nws+hipone.cia
>map = 2/1/1+1/1/2
>r
>
>e
>
>EOF
>
>gpend
>--------------------
>--------------------
>gdradr <<EOF
>PROJ     = lcc/25;-103;60
>!PROJ     = mer
>!GRDAREA  = 38.85;-75.64;41.35;-73.00
>!GRDAREA  = 33.85;-79.80;41.8;-72.0
>!GRDAREA  = 37.85;-76.80;41.8;-72.0
>GRDAREA  =  33.85;-79.80;41.8;-71.0
>KXKY     = 630;634
>!GDPFUN   = n0r ! net
>GDPFUN   = ntp
>!GDFILE   = YYYYMMDD_radr.gem
>GFUNC    = ntp
>GDFILE   = nj-dix-ntp.gem
>RADTIM   = current
>RADDUR   = 600
>RADFRQ   =
>CPYFIL   = 
>STNFIL   = /home/dana/nnexrad/nexrad_dix.tbl
>MAXGRD   = 200
>RADMODE  = PC
>
>r
>  
>e
>EOF
>
>gpend
>
>
>Thanks!
>Dana
>
>-- 
>-----------------------------------------------------------
>Dana Price                        <address@hidden>
>Systems Administrator                   Voice: 732-932-5833
>Rutgers, The State University           Fax:   732-932-8644
>Department of Environmental Sciences
>Center for Environmental Prediction
>----------------------------------------------------------- 
>
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