GRDINFO -- Lists, modifies, or statistically analyzes grid point values
   GRDINFO sdataset operator ddatset <keywords>
Parameters:
   sdataset | source ADDE dataset name and absolute position; specify as
              group/descriptor.position or alias.position; only positive
              integers or ALL (all positions) are valid for position
              (no def for group/descriptor or alias; def=ALL for position)
   operator | EDIT, HIST, LIST, or STAT (def)
   ddataset | destination of edited data, if EDIT selected; ignored
              otherwise; must include position
Keywords:
***************************  Search Keywords  ****************************
   DAY=d1..dn | search for grids with these days
   DRAnge=bday eday inc | search for grids in the range of days from
                          bday through eday incrementing by inc days;
                          (no def for bday, eday def=bday, inc def=1)
   FDAy= | search for grids with this forecast day; calculated by adding
           the grid's fhour to its day and time, e.g., a grid with
           day=96300, time=12 and fhour=72 has fday=95303; you cannot use
           FDAY with FHOUR or FRANGE keywords
   FHOur=h1..hn | search for grids with these forecast hours; you cannot
                  use FHOUR with FRANGE, FDAY or FTIME keywords
   FRANGe=bhr ehr inc | search for grids in the range of forecast hours
                        from bhr through ehr incrementing by inc hours (no
                        def for bhr; ehr def=bhr; inc def=1); you cannot
                        use FRANGE with FHOUR, FDAY or FTIME keywords
   FTIme= | search for grids with this forecast time; calculated by
            adding the grid's fhour to its time, e.g., a grid with
            time=12 and fhour=18 has ftime=6; you cannot use FTIME with
            FHOUR or FRANGE keywords
   GPRo= | search for grids with this projection; valid entries include
           MERC, PS, LAMB and EQUI
   GRId=bgrid egrid | operate on grids bgrid through egrid; use a number
                      or LAST (last grid) for bgrid and egrid (no def for
                      bgrid, egrid def=bgrid); see the Remarks
   LEV=l1[u1]..ln[un] | search for grids with the specified levels and
                        units, e.g., SFC, 1000[MB], 5000[M]; units are
                        optional but must be in square brackets if
                        specified
   PARam=p1..pn | search for grids with these parameters, e.g., T, Z, RH
   SRC=s1..sn | search for grids from these sources, e.g., MDX, MRF, ETA
   TIMe=t1..tn | search for grids with these times
   TRAnge=btim etim inc | search for grids in the range of times from btim
                          through etim incrementing by inc hours (no def
                          for btim, etim def=btim, inc def=one hour)
************************  Derived Grid Keywords    ***********************
   DERive= | search for the specified derived parameter by searching for
             the necessary component grids, e.g., VOR, DVG, TD, DIR, etc;
             you cannot specify both DERIVE and PARAM; see the Remarks
   MERidional=YES | add correction term to account for convergence of
                    the meridians at the poles
             =NO  | does not add a correction term (def); only valid with
                    DERIVE=ABV, DSH, DST, DVG, or VOR; see User's Guide
   PLAnet= | planet on which the derive calculations are done; valid
             options are MERCURY, VENUS, EARTH, MARS, JUPITER, SATURN,
             NEPTUNE, URANUS (def=EARTH)
********************  Mathematical Operations Keywords *******************
   Gn='clause1; clause2; ..; clausen' |
      grids to use with the MATH keyword; use a number between 1 and 99 in
      the keyword name (G1,G2,..,G99); each keyword specifies a single grid
      determined by its select clauses; separate clauses with semicolons
      and enclose the entire string of clauses with single quotes; specify
      clauses using the following format:
           searchkeyword value
      valid options for searchkeyword are DAY,FHOUR,GPRO,GRID,LEV,PARAM,
      SRC,TIME; by default, subsequent Gn keywords inherit the select
      clauses of the previous Gn keyword; e.g., to request 850 and 1000 mb
      height grids from the 0 UTC MRF run, specify:
         G1='LEV 850;PARAM Z;TIME 0;SRC MRF'  G2='LEV 1000'
   MATh='expression' | mathematical operation to perform on the grids
                       specified with the Gn keywords; single quotes are
                       required; see the Remarks
   NEWpar=param punit level lunit | parameter and level values to assign
              to the grid header of the grid created with the MATH
              keyword, where:
              param - grid parameter; 4 character max (def=MATH)
              punit - units of grid parameter; 4 character max (def=NONE)
              level - grid level (def=from grid)
              lunit - units of grid level; 2 character max (def=from grid)
   INFo='text' | string placed in the header of the copied grid when the
                 MATH keyword is used; maximum of 48 characters
********************  Grid Point Selection Keywords  *********************
   ROW=brow erow | range of rows to list or edit; you can specify MAX for
                   the last row in the grid (def=1 MAX   for STAT and HIST
                   options; def=1 brow   for LIST and EDIT options)
   COL=bcol ecol | range of columns to list or edit; you can specify MAX
                   for the last column in the grid (def=1 MAX   for STAT
                   and HIST options; def=1 bcol   for LIST and EDIT optns)
   LAT=slat nlat | latitude range to list or edit, where 'slat' and 'nlat'
                   are southern and northern latitude limits, respectively
                   (def=grid latitude extents)
   LON=elon wlon | longitude range to list or edit, where 'elon' & 'wlon'
                   are eastern and western longitude limits, respectively
                   (def=grid longitude extents)
   RANge=bval eval | grid point values to list or edit; specify bval-eval
                     range or MISS for missing values (def=all values)
*************************  EDIT Option Keywords  *************************
   DEL=YES | delete the destination grid file before writing (def=NO); see
             the Remarks
   DGRid= | beginning grid number to place grids in destination grid file;
            may overwrite existing grids (def=append after last grid in
            the grid file); see the Remarks
   MAXgrd= | maximum number of grids the newly created destination grid
             file can store (def=1000); see the Remarks
   TITLE='text' | title of the newly created destination grid file; 32
                  characters maximum; see the Remarks
   VALue= | numeric value (or MISS) to assign to grid points specified
            with grid point selection keywords
************************* Output Keywords  *******************************
   BINsize= | size of each bin in the histogram; valid with the HIST
              option only (def=data dependant)
   BYTecount=YES | lists the number of bytes received from the server
            =NO  | does not list the number of bytes (def)
   FORmat= | format specification for listing output; if multiple PARAMs
             are requested, FORMAT can not be used; see the User's Guide
   NUM=    | number of grids matching the criteria defined with the search
             keywords to examine; e.g., if you specify NUM=50, the first
             50 grids matching the search keywords are used (def=1)
      =ALL | examine all grids matching the search keywords
   UNIt= | units of data, default is native units; if multiple PARAMs
           are requested, UNIT can not be specified
Remarks:
   More than 1 grid can be altered using the EDIT operator; however, only
   one specific value can be used to modify all the grids to be edited.

   If you specify DEL=YES or the position number of a nonexistent or empty
   grid file in the ddataset parameter, grids are written into a newly
   created grid file whose attributes are as in keywords MAXGRD and TITLE.

   Using the DGRID keyword may result in grids being overwritten in the
   destination grid file. For example, if the destination grid file has
   50 grids (in grids 1 to 50) and you specify NUM=10 DGRID=25, the new
   grids will overwrite grids 25 to 34 in the destination grid file.

   The GRID keyword locates grids from the grid file specified by the
   sdataset position number. The default value in sdataset, ALL, is
   ignored; therefore, you must specify a position. When using the GRID
   keyword, do not specify additional search keywords or NUM.

   Specifying both a RANGE and a LAT/LON or ROW/COL keywords results in
   the intersection of those parameters; further focusing in on the grid
   points to be examined.

   A variety of common meteorological parameters can be derived using
   the DERIVE keyword. These include VOR (vorticity), ABV (absolute
   vorticity), DSH (shear deformation), DST (stretching deformation),
   DVG (divergence), SPD (speed), DIR (direction), TD (dewpoint),
   COR (Coriolis parameter), and BETA (Beta parameter). Only one derived
   parameter can be specified at a time; however, multiple levels or
   times (for example) can be requested.

   The MATH keyword defines the operation to perform on the specified
   Gn grids. For example, if G1='PARAM Z;LEV 500;TIME 12;SRC MRF'
   G2='LEV 1000' MATH='G1-G2' is entered, a 1000 mb height grid will be
   subtracted from a 500 mb height grid, creating a 1000-500 mb thickness
   grid for the 12 UTC MRF model run. The math operators valid in the MATH
   keyword are +,-,/,*,**,SQRT,EXP,LOG,LOG10,SIN,COS,TAN,ASIN,ACOS,ATAN,
   ABS,MIN,MAX,DDX,DDY,DELSQ,COR,BETA,LAT, and LON. See the McIDAS User's
   Guide for definitions of the operators.
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