This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.
Massoud, GDLIST will output all data values of a parameter at a grid point. As GDINFO shows, there are 2 different CAPE grids in the broadcast. One based on surface conditions (eg GDVCORD=NONE, GLEVEL=0), and the other based on the boundary layer (0 to 180mb above the ground, GVCORD=PDLY, GLEVEL=180:0), eg: GDFILE = nam80 LSTALL = yes OUTPUT = t GDATTIM = all GLEVEL = all GVCORD = all GFUNC = cape GEMPAK-GDINFO>r GRID FILE: /data/ldm/gempak/model/nam/2007071012_nam211.gem GRID NAVIGATION: PROJECTION: LCC ANGLES: 25.0 -95.0 25.0 GRID SIZE: 93 65 LL CORNER: 12.19 -133.46 UR CORNER: 57.29 -49.38 GRID ANALYSIS BLOCK: UNKNOWN ANALYSIS TYPE Number of grids in file: 1847 Maximum number of grids in file: 5000 NUM TIME1 TIME2 LEVL1 LEVL2 VCORD PARM 5 070710/1200F000 180 0 PDLY CAPE 160 070710/1200F000 0 NONE CAPE 171 070710/1200F006 180 0 PDLY CAPE 325 070710/1200F006 0 NONE CAPE 340 070710/1200F012 180 0 PDLY CAPE 493 070710/1200F012 0 NONE CAPE 509 070710/1200F018 180 0 PDLY CAPE 659 070710/1200F018 0 NONE CAPE 675 070710/1200F024 180 0 PDLY CAPE 825 070710/1200F024 0 NONE CAPE 843 070710/1200F030 180 0 PDLY CAPE 996 070710/1200F030 0 NONE CAPE 1011 070710/1200F036 180 0 PDLY CAPE 1164 070710/1200F036 0 NONE CAPE 1180 070710/1200F042 180 0 PDLY CAPE 1332 070710/1200F042 0 NONE CAPE 1347 070710/1200F048 180 0 PDLY CAPE 1500 070710/1200F048 0 NONE CAPE 1517 070710/1200F054 180 0 PDLY CAPE 1672 070710/1200F054 0 NONE CAPE 1685 070710/1200F060 180 0 PDLY CAPE 1840 070710/1200F060 0 NONE CAPE Parameters requested: GDFILE,LSTALL,OUTPUT,GDATTIM,GLEVEL,GVCORD,GFUNC. GEMPAK-GDINFO> Sample output from GDLIST would look like: GDATTIM = f000 GLEVEL = 0 GVCORD = none GFUNC = cape GDFILE = nam80 GAREA = dset PROJ = def SCALE = 0 OUTPUT = t GEMPAK-GDLIST>r Creating process: gn for queue 28155 GDLIST PARAMETERS: Grid file: nam80 GRID IDENTIFIER: TIME1 TIME2 LEVL1 LEVL2 VCORD PARM 070710/1200F000 0 NONE CAPE GAREA: dset SCALE FACTOR : 10** 0 OUTPUT: TERM/ MINIMUM AND MAXIMUM VALUES 0.00 4860.00 Enter <cr> to accept parameters or type EXIT: Grid file: nam80 GRID IDENTIFIER: TIME1 TIME2 LEVL1 LEVL2 VCORD PARM 070710/1200F000 0 NONE CAPE AREA: dset GRID SIZE: 93 65 COLUMNS: 1 93 ROWS: 1 65 Scale factor: 10** 0 COLUMN: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 ROW 65 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.00 60.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 80.00 120.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.00 20.00 0.00 0.00 20.00 0.00 0.00 0.00 0.00 0.00 20.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.00 20.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 20.00 40.00 40.00 (etc). It is up to you to determine the ROW/COLUMN locations of the points for your matlab display. Alternatively, in GDCSV, similar input can be used, and output looks like: 93, 65, 57.2895, -49.3846, 40.00000 where the "comma separated values" (ie the name CSV) are column, row, lat, lon, and the value of the GFUNC. The tutorial explains the concepts of a vertical coordinate, a level, and grid navigation. These should be familiar concepts for looking at the gridded data. Steve Chiswell Unidata User Support > Hi Steve, > > Thanks for getting back with me again. You brought up a > good point in your email this afternoon regarding about > GDLIST or GDCSV. It turns out that I'm not particularly > interested in outputting an entire model run, but rather > to output a grid of a desired product of my choosing. If > possible, I would like to use either program and convert > the 12-hr precip analysis, LI, and CAPE, from NAM 211 > and/or GFS 211 to ASCII text. I have already displayed > these data products on GEMPAK for analysis and what I hope > to accomplish as part my research is to convert these > products to ASCII, examine their text file, and display > them again except this time on MATLAB. Therefore, will > GDLIST or GDCSV help me accomplish this task or will I > have to resort to a grib decoder (i.e., wgrib) instead? > > If GDLIST or GDCSV were to work, I'm still not sure what > appropriate parameters will be needed for GFUNC, GAREA, > PROJ, SCALE, and etc. I have looked through the tutorial > today, but I may need some guidance for these particular > products. Any suggestions? > > Thanks so much for your time. > > Massoud Fazal > UARC Systems Teaching Institute > NASA Ames Research Center > Moffett Field, CA 94035 > (650)-604-0225 > > Ticket Details =================== Ticket ID: RUX-727661 Department: Support GEMPAK Priority: High Status: Closed