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Greg, The GINI National Mosaic in the IDD stream with feedtype FNEXRAD are the following: 1km: N0R product composite rad/NEXRCOMP/1km/n0r_20040408_2111 2km: N1P product composite rad/NEXRCOMP/2km/n1p_20040408_2112 4km: NTP product composite rad/NEXRCOMP/4km/ntp_20040408_2114 YYYYMMDD HHNN The format of the GINI header is described in the NESDIS ICD: http://www.nws.noaa.gov/noaaport/document/icd_ch4.pdf The products are created in lamber conformal, eg table 4.4A in the above PDF. The Actual GINI header is preceeded by a 21 byte WMO format header. That plus the 512 bytes of GINI header give 533 bytes, followed by the PNG format product. We have a program which will unpack the PNG into the raster if you desire: pngg2gini in the ldm-mcidas.tar.Z package you can obtain from the pub/binary directory of ftp.unidata.ucar.edu. Or, our GEMPAK distribution will read the PNG directly, or as uncompressed into the standard raster (byte 43 in the GINI header signals compression....I am using a value of 128 to signal that PNG is used for the raster). You can also just pull out the PNG and display it directly from the 522 byte offset. You will find the following information from the GINI header: Nx = 4736 Ny = 3000 Proj = LCC with stdlon = -100 and tangent lat = 40. For the products, I have the band values defined as: !Prod band ncal units,Calval_1;....;calval_n N0Z 25 1 dBZ,0,255,0,75 NET 26 1 KFt,0,255,0,85 N0R 27 1 dBZ,0,105,-30,75 NCR 28 1 dBZ,0,105,-30,75 NVL 29 1 Kg/m**2,0,255,0,85 N1P 30 3 inches,10,110,0,2;110,210,2,6;210,255,6,12 NTP 31 3 inches,10,110,0,4;110,220,4,12;210,255,12,24 The calibration information is signaled with byte 47 of the header=128 and I described the format: http://www.unidata.ucar.edu/projects/coohl/mhonarc/MailArchives/gempak/msg04994.html For the n0r, the calibration is simply byte values 0 to 105 represent dbz values of -30 to 75. In the case of N1P, there are 3 segments of the calibration: values 10 to 110 scale to 0 to 2 inches values 110 to 210 scale to 2 to 6 inches values 210 to 255 scale to 6 to 12 inches The non linear calibration (eg 3 linear segments) is based on the fact that the NIDS products have discrete values, and the bin values are not linearly spaced. The GRIB products currently are 6km national and 1km regional in the FNEXRAD feed using product IDs: radar_mosaic_national !grib/unidata/1/#255/200404082126/F000/N0R/sfc! 000000 radar_mosaic_regional_ilx !grib/unidata/2/#255/200404082126/F000/N0R/sfc! 000000 The #255 is the GDS defined grid number. These use a model center id 60 (eg NCAR/UCAR) with a subcenter id of 1 (my self defined unidata subcenter). The regional product is centered on the station id in the product name (and is relocatable by one of our universities). The reason for the 6km grib for national was a limitation on the user end to handle the number of grid points in a 1km product. I have a web page set up that describes the products: my.unidata.ucar.edu/content/software/gempak/examples/gdradr http://motherlode.ucar.edu/unidata/images/nids/gdradr.html Steve Chiswell Unidata User Support On Mon, 2004-04-05 at 20:44, Greg Thompson wrote: > Steve, > > a number of months ago you mentioned the existence of a national > radar mosaic product you created. Can you tell me the header > to pick it up over LDM? I recall that the product is 533 bytes of > header data followed by a PNG image. Can you tell me more about the > projection information and anything I can glean from the header? > Also is it little-endian or big? > > I'm working to replace Peter Neilley's software that creates NIDS > single-site images as well as his display of the WSI-Nowrad product > since that has restrictions placed upon it. RAP can no longer support > his software and I've replaced all his single-site stuff with > improved images. Now, I'm looking to re-map sectors of your hi-res > mosaic into regions around the country (probably the same sectors > as seen on my satellite and surface data pages). > > Also, you mentioned you were planning to GRIB a radar mosaic product. > That item had 6-km spacing whereas the PNG file was 1-km from what > I recall. I'd truly love to get the 1-km data as a GRIB file so I > could manipulate any way I desire but I'll take what's available now > if you can point me in the right places. > > Thanks!