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Cool. Yes, the values I'm getting from the bit of code I just wrote to decode this correspond exactly to those in the table. Thanks again for making these composites. They're great! ----- Original Message ----- From: "Unidata Support" <address@hidden> To: "David Wojtowicz" <address@hidden> Cc: "Unidata Support" <address@hidden> Sent: Wednesday, October 23, 2002 6:03 PM Subject: 20021023: 20021023: converting GINI composite radar image values to dbZ > > > David, > > Correct. Forgot to mention the units bytes and the scaling by 10000. > > The $NAWIPS/unidata/programs/nex2gini program I created uses the > data blocks in the $GEMTBL/unidata/nex2gini.tbl file for > the varous "stretch" sections. In the case of N0R, there is only 1 > calibrated range. For, N1P there are 3 (because the LevelIII > bins for the data range are much larger at the high end and the > difference between ND and "0.00"). > > The table I'm using currently looks like: > ! > ! > !Prod band ncal units,Calval_1;....;calval_n Prod_header > N0Z 25 1 dBZ,0,255,0,75 TICZ99 CHIZ > NET 26 1 KFt,0,255,0,85 TICZ99 CHIZ > N0R 27 1 dBZ,0,105,-30,75 TICZ99 CHIZ > NCR 28 1 dBZ,0,105,-30,75 TICZ99 CHIZ > NVL 29 1 Kg/m**2,0,255,0,85 TICZ99 CHIZ > N1P 30 3 inches,10,110,0,2;110,210,2,6;210,255,6,12 TICZ99 CHIZ > NTP 31 3 inches,10,110,0,4;110,220,4,12;210,255,12,24 TICZ99 CHIZ > > Steve Chiswell > Unidata User SUpport > > > >From: "David Wojtowicz" <address@hidden> > >Organization: UCAR/Unidata > >Keywords: 200210232255.g9NMtTp06497 > > > > >----- Original Message ----- > >From: "Unidata Support" <address@hidden> > >To: <address@hidden> > >Cc: <address@hidden> > >Sent: Wednesday, October 23, 2002 4:58 PM > >Subject: 20021023: converting GINI composite radar image values to dbZ > > > > > >> > >> David, > >> > >> I provide a calibration block in the image (in the unused portion > >> of the GINI header) that is used to obtain the image calibration bar > >> values. > >> > >> I created a section of code in $GEMPAK/source/gemlib/im/imgi2gm.f > >> with: > >> C > >> C* Get calibration Block if it exists. > >> C* Currently, only Unidata calibrations exist, using > >> C* Word 47 = 128 > >> C* to signal that a calibration block is present. > >> C > >> At present the format is the number of calibration ranges N, followed by > >> N * 4 values where each set of 4 represents the pixel min, max and > >> data value min max they corespond to. > >> > >Steve thanks for the info. > > > >I was a bit confused at first, but it looks like starting at Octet 48, there > >is: > > > > 1) a space padded 8 byte character array with the name of the units > > 2) followed by a 1 byte size, N > > 3) followed by N*4 4-byte values (words) that correspond to the values you > >mention above that are multiplied by 10000 > > > >Is this the correct interpretation of the Unidata calibration section? > > > >Thanks! > > > > **************************************************************************** < > Unidata User Support UCAR Unidata Program < > (303)497-8643 P.O. Box 3000 < > address@hidden Boulder, CO 80307 < > -------------------------------------------------------------------------- -- < > Unidata WWW Service http://www.unidata.ucar.edu/ < > **************************************************************************** < >