gmtinfo(1) GMT gmtinfo(1)
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[/dza|] ] [ -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 warn-
ings 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 granular-
ity 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[/dza|]
Report the min/max of the first n columns to the nearest multi-
ple 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 sec-
ond 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-registra-
tion. 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 pro-
grams using FFTs. Use -Isdx[/dy] to report an extended region
optimized to give grid dimensions for fastest results in pro-
grams 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 hori-
zontal 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[+ccol]
Report the min/max of the first (0ath) column to the nearest
multiple of dz and output this as the string -Tzmin/zmax/dz. To
use another column, append +ccol. Only works when -I is
selected.
-V[level] (more a|)
Select verbosity level [c].
-bi[ncols][t] (more a|)
Select native binary input. [Default is 2 input columns].
-dinodata (more a|)
Replace input columns that equal nodata with NaN.
-e[~]^<i>apattern^<i>a | -e[~]/regexp/[i] (more a|)
Only accept data records that match the given pattern.
-f[i|o]colinfo (more a|)
Specify data types of input and/or output columns.
-g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u] (more a|)
Determine data gaps and line breaks.
-h[i|o][n][+c][+d][+rremark][+rtitle] (more a|)
Skip or produce header record(s).
-icols[+l][+sscale][+ooffset][,^<i>a|] (more a|)
Select input columns and transformations (0 is first column).
-ocols[,a|] (more a|)
Select output columns (0 is first column).
-r (more a|)
Set pixel node registration [gridline].
-:[i|o] (more a|)
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 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.
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 FOR-
MAT_DATE_OUT and FORMAT_CLOCK_OUT, whereas general floating point val-
ues are formatted according to FORMAT_FLOAT_OUT. Be aware that the for-
mat 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 set-
ting.
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 calcu-
lated. Instead, specify your interval in the same units as the current
setting of TIME_UNIT.
SEE ALSO
gmt(1), gmtconvert(1), psxy(1)
COPYRIGHT
2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
5.4.2 Jun 24, 2017 gmtinfo(1)
gmt5 5.4.2 - Generated Wed Jun 28 16:27:24 CDT 2017