NAME

       gmtinfo - Return information about data tables

SYNOPSIS

       gmtinfo  [ table ] [ a|f|s ] [  ] [ [dx[/dy]] ] [ L|l|H|hcol ] [ [p|f|s]dx[/dy[/dz...] ] [
       [x][y] ] [ dz[/col] ] [ [level] ] [ -bi<binary> ] [ -di<nodata> ] [ -f<flags> ] [ -g<gaps>
       ] [ -h<headers> ] [ -i<flags> ] [ -o<flags> ] [ -r ] [ -:[i|o] ]

       Note: No space is allowed between the option flag and the associated arguments.

DESCRIPTION

       gmtinfo  reads  its standard input [or from files] and finds the extreme values in each of
       the columns. It recognizes NaNs and will print warnings if the number of columns vary from
       record  to  record.  As  an  option,  gmtinfo  will find the extent of the first n columns
       rounded up and down to the nearest multiple of the supplied increments. By  default,  this
       output  will  be  in the form -Rw/e/s/n which can be used directly in the command line for
       other programs (hence only dx and dy are needed), or the output will be in column form for
       as  many  columns  as  there are increments provided. A similar option (-T) will provide a
       -Tzmin/zmax/dz string for makecpt.

REQUIRED ARGUMENTS

       None.

OPTIONAL ARGUMENTS

       table  One or more ASCII (or binary, see -bi[ncols][type]) data table  file(s)  holding  a
              number of data columns. If no tables are given then we read from standard input.

       -Aa|f|s
              Specify  how  the  range  should be reported. Choose -Aa for the range of all files
              combined, -Af to report the range for each file separately, and -As to  report  the
              range for each segment (in multisegment files) separately. [Default is -Aa].

       -C     Report  the  min/max  values per column in separate columns [Default uses <min/max>
              format]. When used, users may also use -o to limit which output columns  should  be
              reported [all].

       -D     Modifies  results  obtained  by  -I by shifting the region to better align with the
              center of the  data.   Optionally,  append  granularity  for  this  shift  [Default
              performs an exact shift].

       -EL|l|H|hcol
              Returns  the record whose column col contains the minimum (l) or maximum (h) value.
              Upper case (L|H) works on absolute value of the data. In case of multiple  matches,
              only  the  first record is returned. If col is not specified we default to the last
              column in the data.

       -I[p|f|s]dx[/dy[/dz...]
              Report the min/max of the first n columns to the nearest multiple of  the  provided
              increments  (separate  the n increments by slashes), and output results in the form
              -Rw/e/s/n (unless -C is set). If only one increment is given we also use it for the
              second  column (for backwards compatibility). To override this behavior, use -Ipdx.
              If the input x- and y-coordinates all have the same phase shift relative to the  dx
              and dy increments then we use those phase shifts in determining the region, and you
              may use  -r  to  switch  from  gridline-registration  to  pixel-registration.   For
              irregular  data  both  phase  shifts  are  set  to  0  and  the -r is ignored.  Use
              -Ifdx[/dy] to report an extended region  optimized  to  give  grid  dimensions  for
              fastest  results  in  programs  using  FFTs.   Use -Isdx[/dy] to report an extended
              region optimized to give grid dimensions  for  fastest  results  in  programs  like
              surface.   If dx is given as - then the actual min/max of the input is given in the
              -R string.

       -S[x][y]
              Add extra space for error bars. Useful together  with  -I  option  and  when  later
              plotting  with psxy -E. -Sx leaves space for horizontal error bars using the values
              in third (2) column. -Sy leaves space for vertical error bars using the  values  in
              third  (2)  column. -S or -Sxy leaves space for both error bars using the values in
              third and fourth (2 and 3) columns.

       -Tdz[/col]
              Report the min/max of the first (0'th) column to the nearest  multiple  of  dz  and
              output  this  in the form -Tzmin/zmax/dz.  To use another column, append /col. Only
              works when -I is selected.

       -V[level] (more ...)
              Select verbosity level [c].

       -bi[ncols][t] (more ...)
              Select native binary input. [Default is 2 input columns].

       -dinodata (more ...)
              Replace input columns that equal nodata with NaN.

       -f[i|o]colinfo (more ...)
              Specify data types of input and/or output columns.

       -g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u] (more ...)
              Determine data gaps and line breaks.

       -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
              Skip or produce header record(s).

       -icols[l][sscale][ooffset][,...] (more ...)
              Select input columns (0 is first column).

       -ocols[,...] (more ...)
              Select output columns (0 is first column).

       -r (more ...)
              Set pixel node registration [gridline].

       -:[i|o] (more ...)
              Swap 1st and 2nd column on input and/or output.

       -^ or just -
              Print a short message about the syntax of the command, then exits (NOTE: on Windows
              use just -).

       -+ or just +
              Print  an  extensive  usage  (help)  message,  including  the  explanation  of  any
              module-specific option (but not the GMT common options), then exits.

       -? or no arguments
              Print a complete usage (help) message, including the explanation of  options,  then
              exits.

       --version
              Print GMT version and exit.

       --show-datadir
              Print full path to GMT share directory and exit.

ASCII FORMAT PRECISION

       The  ASCII  output formats of numerical data are controlled by parameters in your gmt.conf
       file. Longitude and latitude are formatted  according  to  FORMAT_GEO_OUT,  whereas  other
       values are formatted according to FORMAT_FLOAT_OUT. Be aware that the format in effect can
       lead to loss of precision in the output, which can lead to various problems downstream. If
       you  find  the  output  is not written with enough precision, consider switching to binary
       output (-bo if available) or specify more decimals using the FORMAT_FLOAT_OUT setting.

EXAMPLES

       To find the extreme values in the file ship_gravity.xygd:

              gmt info ship_gravity.xygd

       Output should look like

              ship_gravity.xygd: N = 6992 <326.125/334.684> <-28.0711/-8.6837> <-47.7/177.6> <0.6/3544.9>

       To find the extreme values in the file track.xy to the nearest  5  units  but  shifted  to
       within 1 unit of the data center, and use this region to draw a line using psxy, run

              gmt psxy `gmt info -I5 -D1 track.xy` track.xy -Jx1 -B5 -P > track.ps

       To  find  the min and max values for each of the first 4 columns, but rounded to integers,
       and return the result individually for each data file, use

              gmt info profile_*.txt -C -I1/1/1/1

BUGS

       The -I option does not yet work properly with time series data (e.g.,  -f0T).  Thus,  such
       variable  intervals as months and years are not calculated. Instead, specify your interval
       in the same units as the current setting of TIME_UNIT.

SEE ALSO

       gmt, gmtconvert

COPYRIGHT

       2015, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe