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x2sys_datalist(1)                     GMT                    x2sys_datalist(1)


       x2sys_datalist - Extract content of track data files


       x2sys_datalist  track(s)  -TTAG [  -A ] [  -E ] [  -Fname1,name2,a| ] [
       -I[list] ] [  -L[corrtable] ] [  -Rregion ] [  -S ] [ [  -V[level] ]  [
       -bobinary ] [ -donodata ] [ -hheaders ]

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


       x2sys_datalist reads one or more files and produces a single ASCII  [or
       binary]  table. The files can be of any format, which must be described
       and passed with the  -T option. You may limit  the  output  to  a  geo-
       graphic  region, and insist that the output from several files be sepa-
       rated by a multiple segment header. Only the named data fields will  be
       output [Default selects all columns].


       tracks Can  be  one  or more ASCII, native binary, or COARDS netCDF 1-D
              data files. To supply the data files via a text file with a list
              of  tracks  (one per record), specify the name of the track list
              after a leading equal-sign (e.g., =tracks.lis). If the names are
              missing their file extension we will append the suffix specified
              for this TAG. Track files will be searched for first in the cur-
              rent   directory   and  second  in  all  directories  listed  in
              $X2SYS_HOME/TAG/TAG_paths.txt (if it exists). [If $X2SYS_HOME is
              not  set  it  will default to $GMT_SHAREDIR/x2sys]. (Note: MGD77
              files will also be looked for via MGD77_HOME/mgd77_paths.txt and
              *.gmt  files  will  be  searched  for via $GMT_SHAREDIR/mgg/gmt-

       -TTAG  Specify the x2sys TAG which tracks the attributes of  this  data


       -A     Eliminate COEs by distributing the COE between the two tracks in
              proportion to track  weight.  These  (dist,  adjustment)  spline
              knots files for each track and data column are called track.col-
              umn.adj and are expected to be in the $X2SYS_HOME/TAG directory.
              The  adjustments  are  only  applied if the corresponding adjust
              file can be found [No residual adjustments]

       -E     Enhance ASCII output by writing GMT segment headers between data
              from each track [no segment headers].

              Give  a  comma-separated sub-set list of column names defined in
              the definition file. [Default selects all data columns].

              Name of ASCII file with a list of track names (one  per  record)
              that should be excluded from consideration [Default includes all

              Apply optimal corrections to columns where such corrections  are
              available.  Append the correction table to use [Default uses the
              correction table TAG_corrections.txt which is expected to reside
              in  the $X2SYS_HOME/TAG directory]. For the format of this file,
              see CORRECTIONS below.

              west, east, south, and north specify the region of interest, and
              you    may    specify    them   in   decimal   degrees   or   in
              [A+-]dd:mm[][W|E|S|N] format Append +r if lower left  and
              upper  right  map  coordinates are given instead of w/e/s/n. The
              two shorthands -Rg and -Rd stand for global  domain  (0/360  and
              -180/+180  in longitude respectively, with -90/+90 in latitude).
              Alternatively for grid creation, give Rcodelon/lat/nx/ny,  where
              code  is a 2-character combination of L, C, R (for left, center,
              or right) and T, M, B for top, middle, or bottom. e.g.,  BL  for
              lower  left.  This indicates which point on a rectangular region
              the lon/lat coordinate refers to, and the grid dimensions nx and
              ny with grid spacings via -I is used to create the corresponding
              region.  Alternatively, specify the name  of  an  existing  grid
              file  and  the -R settings (and grid spacing, if applicable) are
              copied from the grid. Appending +uunit expects projected (Carte-
              sian)  coordinates  compatible  with  chosen -J and we inversely
              project to determine actual rectangular geographic region.   For
              perspective view (-p), optionally append /zmin/zmax.  In case of
              perspective view (-p), a z-range (zmin, zmax) can be appended to
              indicate  the  third  dimension. This needs to be done only when
              using the -Jz option, not when using only the -p option. In  the
              latter  case a perspective view of the plane is plotted, with no
              third    dimension.    For    Cartesian    data    just     give
              xmin/xmax/ymin/ymax.  This  option limits the COEs to those that
              fall inside the specified domain.

       -S     Suppress output records where  all  the  data  columns  are  NaN
              [Default will output all records].

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

       -bo[ncols][type] (more a|)
              Select native binary output.

       -donodata (more a|)
              Replace output columns that equal NaN with nodata.

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

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

       -+ or just +
              Print an extensive usage (help) message, including the  explana-
              tion  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 all options, then exits.


       To  extract  all data from the old-style MGG supplement file c2104.gmt,
       recognized by the tag GMT:

              gmt x2sys_datalist c2104.gmt -TGMT > myfile

       To make lon,lat, and depth input for blockmean and  surface  using  all
       the  files listed in the file tracks.lis and define by the tag TRK, but
       only the data that are inside  the  specified  area,  and  make  output
       binary, run

              gmt x2sys_datalist =tracks.lis -TTRK -Fon,lat,depth -R40/-30/25/35 -bo >


       The  correction table is an ASCII file with coefficients and parameters
       needed to carry out corrections. This  table  is  usually  produced  by
       x2sys_solve.  Comment records beginning with # are allowed. All correc-
       tion records are of the form

       trackID observation correction

       where trackID is the track name, observation is one  of  the  abbrevia-
       tions for an observed field contained in files under this TAG, and cor-
       rection consists of one or more white-space-separated terms  that  will
       be  subtracted  from the observation before output. Each term must have
       this exact syntax:


       where terms in brackets are optional (the brackets themselves  are  not
       used  but  regular  parentheses  must be used exactly as indicated). No
       spaces are allowed except between terms. The factor is the amplitude of
       the basis function, while the optional function can be one of sin, cos,
       or exp. The optional scale and origin can  be  used  to  translate  the
       argument  (before  giving  it  to the optional function).  The argument
       abbrev is one of the abbreviations for columns known to this TAG.  How-
       ever,  it  can  also  be  one  of  the  three auxiliary terms dist (for
       along-track distances), azim for along-track  azimuths,  and  vel  (for
       along-track  speed);  these are all sensitive to the -C and -N settings
       used when defining the  TAB;  furthermore,  vel  requires  time  to  be
       present  in  the  data. If origin is given as T it means that we should
       replace it with the value of abbrev for the very first  record  in  the
       file  (this  is  usually  only done for time). If the first data record
       entry is NaN we revert origin to zero.  Optionally,  raise  the  entire
       expression  to  the given power, before multiplying by factor. The fol-
       lowing is an example of fictitious corrections to the track ABC, imply-
       ing  the  z  column  should  have a linear trend removed, the field obs
       should be corrected by a strange dependency on latitude,  weight  needs
       to  have  1 added (hence correction is given as -1), and fuel should be
       reduced by a linear distance term:

       ABC z 7.1 1e-4*((time-T))

       ABC obs 0.5*exp(-1e-3(lat))^1.5

       ABC weight -1

       ABC fuel 0.02*((dist))


       blockmean(1), gmt(1), surface(1), x2sys_init(1), x2sys_datalist(1),
       x2sys_get(1), x2sys_list(1), x2sys_put(1), x2sys_report(1),


       2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe

5.4.2                            Jun 24, 2017                x2sys_datalist(1)

gmt5 5.4.2 - Generated Thu Jun 29 18:05:33 CDT 2017
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