gmtinfo - Return information about data tables
] [ -Aa
] [ -D
]] ] [
] ] [
...] ] [
] [ -S
] ] [
] ] [ -V
] ] [
binary ] [ -di
nodata ] [ -e
regexp ] [ -f
gaps ] [ -h
headers ] [ -i
flags ] [ -o
flags ] [
] [ -:
No space is allowed between the option flag and the associated
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
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
string for makecpt.
- 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
- 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].
- 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].
- 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].
- 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.
- 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
-Is dx[/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.
- 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.
- 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.
- 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. 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
- -dinodata (more ...)
- Replace input columns that equal nodata with
- -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.
- Determine data gaps and line breaks.
- Skip or produce header record(s).
- Select input columns and transformations (0 is first
- -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.
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.
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.
gmt info profile_.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
option does not yet work properly with time series data (e.g.,
0T). 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.
gmt, gmtconvert, psxy
2017, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe