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

5.2.1                                           January 28, 2016                                   GMTINFO(1gmt)