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[GEMPAK #KTU-213331]: Radar NTP/BRET threshold values
- Subject: [GEMPAK #KTU-213331]: Radar NTP/BRET threshold values
- Date: Thu, 27 Jun 2013 09:46:12 -0600
Hi Jim,
The program NEX2GINI uses a file nex2gini.tbl which is viewable here:
https://github.com/Unidata/gempak/blob/master/gempak/tables/unidata/nex2gini.tbl
It contains a line for NTP with three groups of precip <=> pixel equivalence:
!Prod band ncal units,Calval_1;....;calval_n Prod_header
NTP 31 3 inches,10,110,0,4;110,220,4,12;210,255,12,24 TICZ99 CHIZ
this entry translates to:
* three calibration ranges
* units in inches
* 0-4 inches = 10-110
* 4-12 inches = 110-220
* 12-24 inches = 210-255
So precipitation values can be determined by linearly interpolating values
between the min/max of these three ranges.
-Michael
> Michael,
>
> I can understand the way individual sites report may vary and you use a
> floating scale to standardize the colors for a given amount of precipitation,
> but in the composite BRET file aren't the standardized values sent in the
> composite. My thinking was that the BRET composite file was built into
> something like a satellite IR image file, which has brightness values
> corresponding to certain temperatures and that for NTP, the image
> "brightness" values correspond to certain values, which are reflected in the
> color bar that I see on the McIDAS display of the BRET files (e.g. the color
> bar is always the same and always corresponds to the listed values). Am I
> incorrect to assume that the BRET values should correspond to certain
> precipitation values. Otherwise, I don't see how McIDAS could always use the
> same color bar/values.
>
> Jim
Ticket Details
===================
Ticket ID: KTU-213331
Department: Support GEMPAK
Priority: Normal
Status: Open