1GMTINFO(1) GMT GMTINFO(1)
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6 gmtinfo - Return information about data tables
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9 gmtinfo [ table ] [ -Aa|f|s ] [ -C ] [ -D[dx[/dy]] ] [ -EL|l|H|hcol
10 ] [ -F[i|d|t] ] [ -I[p|f|s]dx[/dy[/dz...] ] [ -L ] [ -S[x][y] ] [
11 -Tdz[+ccol] ] [ -V[level] ] [ -bibinary ] [ -dinodata ] [ -eregexp ] [
12 -fflags ] [ -ggaps ] [ -hheaders ] [ -iflags ] [ -oflags ] [ -r ] [
13 -:[i|o] ]
14 Note: No space is allowed between the option flag and the associated
16 arguments.
17
19 gmtinfo reads its standard input [or from files] and finds the extreme
20 values in each of the columns reported as slash-separated min/max
21 pairs. It recognizes NaNs and will print warnings if the number of col‐
22 umns vary from record to record. The pairs can be split into two sepa‐
23 rate columns by using the -C option. As another option, gmtinfo can
24 find the extent of data in the first two columns rounded up and down to
25 the nearest multiple of the supplied increments given by -I. Such out‐
26 put will be in the text form -Rw/e/s/n, which can be used directly on
27 the command line for other modules (hence only dx and dy are needed).
28 If -C is combined with -I then the output will be in column form and
29 rounded up/down for as many columns as there are increments provided in
30 -I. A similar option (-T) will provide a -Tzmin/zmax/dz string for
31 makecpt.
32
34 None.
35
37 table One or more ASCII (or binary, see -bi[ncols][type]) data table
38 file(s) holding a number of data columns. If no tables are given
39 then we read from standard input.
40 -Aa|f|s
42 Specify how the range should be reported. Choose -Aa for the
43 range of all files combined, -Af to report the range for each
44 file separately, and -As to report the range for each segment
45 (in multisegment files) separately. [Default is -Aa].
46 -C Report the min/max values per column in separate columns
48 [Default uses <min/max> format]. When used, users may also use
49 -o to limit which output columns should be reported [all].
50 -D Modifies results obtained by -I by shifting the region to better
52 align with the center of the data. Optionally, append granular‐
53 ity for this shift [Default performs an exact shift].
54 -EL|l|H|hcol
56 Returns the record whose column col contains the minimum (l) or
57 maximum (h) value. Upper case (L|H) works on absolute value of
58 the data. In case of multiple matches, only the first record is
59 returned. If col is not specified we default to the last column
60 in the data.
61 -F[i|d|t] ]
63 Returns the counts of various records depending on the appended
64 mode: i returns a single record with the total number of tables,
65 segments, data records, header records, and overall records. In
66 contrast, d returns information for each segment in the virtual
67 data set: tbl_number, seg_number, n_rows, start_rec, stop_rec. t
68 does the same but honors the input table organization and thus
69 resets seg_number, start_rec, stop_rec at the start of each new
70 table.
71 -I[p|f|s]dx[/dy[/dz...]
73 Report the min/max of the first n columns to the nearest multi‐
74 ple of the provided increments (separate the n increments by
75 slashes), and output results in the form -Rw/e/s/n (unless -C is
76 set). If only one increment is given we also use it for the sec‐
77 ond column (for backwards compatibility). To override this
78 behavior, use -Ipdx. If the input x- and y-coordinates all have
79 the same phase shift relative to the dx and dy increments then
80 we use those phase shifts in determining the region, and you may
81 use -r to switch from gridline-registration to pixel-registra‐
82 tion. For irregular data both phase shifts are set to 0 and the
83 -r is ignored. Use -Ifdx[/dy] to report an extended region
84 optimized to give grid dimensions for fastest results in pro‐
85 grams using FFTs. Use -Isdx[/dy] to report an extended region
86 optimized to give grid dimensions for fastest results in pro‐
87 grams like surface. If dx is given as - then the actual min/max
88 of the input is given in the -R string.
89 -L Determines common limits across tables (-Af) or segments (-As).
91 If used with -I it will round inwards so that the resulting
92 bounds lie within the actual data domain.
93 -S[x][y]
95 Add extra space for error bars. Useful together with -I option
96 and when later plotting with psxy -E. -Sx leaves space for hori‐
97 zontal error bars using the values in third (2) column. -Sy
98 leaves space for vertical error bars using the values in fourth
99 (3) column. -S or -Sxy leaves space for both error bars using
100 the values in third and fourth (2 and 3) columns.
101 -Tdz[+ccol]
103 Report the min/max of the first (0'th) column to the nearest
104 multiple of dz and output this as the string -Tzmin/zmax/dz. To
105 use another column, append +ccol. Cannot be used together with
106 -I.
107 -V[level] (more ...)
109 Select verbosity level [c].
110 -bi[ncols][t] (more ...)
112 Select native binary input. [Default is 2 input columns].
113 -dinodata (more ...)
115 Replace input columns that equal nodata with NaN.
116 -e[~]"pattern" | -e[~]/regexp/[i] (more ...)
118 Only accept data records that match the given pattern.
119 -f[i|o]colinfo (more ...)
121 Specify data types of input and/or output columns.
122 -g[a]x|y|d|X|Y|D|[col]z[+|-]gap[u] (more ...)
124 Determine data gaps and line breaks.
125 -h[i|o][n][+c][+d][+rremark][+rtitle] (more ...)
127 Skip or produce header record(s).
128 -icols[+l][+sscale][+ooffset][,...] (more ...)
130 Select input columns and transformations (0 is first column).
131 -ocols[,...] (more ...)
133 Select output columns (0 is first column).
134 -r (more ...)
136 Set pixel node registration [gridline].
137 -:[i|o] (more ...)
139 Swap 1st and 2nd column on input and/or output.
140 -^ or just -
142 Print a short message about the syntax of the command, then
143 exits (NOTE: on Windows just use -).
144 -+ or just +
146 Print an extensive usage (help) message, including the explana‐
147 tion of any module-specific option (but not the GMT common
148 options), then exits.
149 -? or no arguments
151 Print a complete usage (help) message, including the explanation
152 of all options, then exits.
153
155 The ASCII output formats of numerical data are controlled by parameters
156 in your gmt.conf file. Longitude and latitude are formatted according
157 to FORMAT_GEO_OUT, absolute time is under the control of FOR‐
158 MAT_DATE_OUT and FORMAT_CLOCK_OUT, whereas general floating point val‐
159 ues are formatted according to FORMAT_FLOAT_OUT. Be aware that the for‐
160 mat in effect can lead to loss of precision in ASCII output, which can
161 lead to various problems downstream. If you find the output is not
162 written with enough precision, consider switching to binary output (-bo
163 if available) or specify more decimals using the FORMAT_FLOAT_OUT set‐
164 ting.
165
167 To find the extreme values in the file ship_gravity.xygd:
168 gmt info ship_gravity.xygd
170 Output should look like
172 ship_gravity.xygd: N = 6992 <326.125/334.684> <-28.0711/-8.6837> <-47.7/177.6> <0.6/3544.9>
174 To find the extreme values in the file track.xy to the nearest 5 units
176 but shifted to within 1 unit of the data center, and use this region to
177 draw a line using psxy, run
178 gmt psxy `gmt info -I5 -D1 track.xy` track.xy -Jx1 -B5 -P > track.ps
180 To find the min and max values for each of the first 4 columns, but
182 rounded to integers, and return the result individually for each data
183 file, use
184 gmt info profile_*.txt -C -I1/1/1/1
186 Given seven profiles with different start and stop positions, we want
188 to find a range of positions, with increment of 5, that are common to
189 all the profiles. We use
190 gmt info profile_[123567].txt -L -I5
192 The file magprofs.txt contains a number of magnetic profiles stored as
194 separate data segments. We need to know how many segments there are
195 and use
196 gmt info magprofs.txt -Fi
198
200 The -I option does not yet work properly with time series data (e.g.,
201 -f0T). Thus, such variable intervals as months and years are not calcu‐
202 lated. Instead, specify your interval in the same units as the current
203 setting of TIME_UNIT.
204
206 gmt, gmtconvert, psxy
207
209 2019, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
2105.4.5 Feb 24, 2019 GMTINFO(1)