Provided by: gmt-common_5.4.3+dfsg-1_all 
NAME
gmtinfo - Return information about data tables
SYNOPSIS
gmtinfo [ table ] [ -Aa|f|s ] [ -C ] [ -D[dx[/dy]] ] [ -EL|l|H|hcol ] [ -F[i|d|t] ] [
-I[p|f|s]dx[/dy[/dz…] ] [ -L ] [ -S[x][y] ] [ -Tdz[+ccol] ] [ -V[level] ] [ -bibinary ] [ -dinodata ]
[ -eregexp ] [ -fflags ] [ -ggaps ] [ -hheaders ] [ -iflags ] [ -oflags ] [ -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.
-F[i|d|t] ]
Returns the counts of various records depending on the appended mode: i returns a single record
with the total number of tables, segments, data records, header records, and overall records. In
contrast, d returns information for each segment in the virtual data set: tbl_number, seg_number,
n_rows, start_rec, stop_rec. t does the same but honors the input table organization and thus
resets seg_number, start_rec, stop_rec at the start of each new table.
-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.
-L Determines common limits across tables (-Af) or segments (-As). If used with -I it will round
inwards so that the resulting bounds lie within the actual data domain.
-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 fourth (3) column. -S or -Sxy leaves space for
both error bars using the values in third and fourth (2 and 3) columns.
-Tdz[+ccol]
Report the min/max of the first (0’th) column to the nearest multiple of dz and output this as the
string -Tzmin/zmax/dz. To use another column, append +ccol. Cannot be used together with -I.
-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.
-e[~]”pattern” | -e[~]/regexp/[i] (more …)
Only accept data records that match the given pattern.
-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 and transformations (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 just use -).
-+ 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 all options, then exits.
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, absolute time is under the control of
FORMAT_DATE_OUT and FORMAT_CLOCK_OUT, whereas general floating point values are formatted according to
FORMAT_FLOAT_OUT. Be aware that the format in effect can lead to loss of precision in ASCII 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
Given seven profiles with different start and stop positions, we want to find a range of positions, with
increment of 5, that are common to all the profiles. We use
gmt info profile_[123567].txt -L -I5
The file magprofs.txt contains a number of magnetic profiles stored as separate data segments. We need
to know how many segments there are and use
gmt info magprofs.txt -Fi
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, psxy
COPYRIGHT
2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
5.4.3 Jan 03, 2018 GMTINFO(1gmt)