Provided by: gmt-common_5.4.3+dfsg-1_all 
NAME
gmtconvert - Convert, Paste, and/or Extract columns from data tables
SYNOPSIS
gmtconvert [ table ] [ -A ] [ -C[+lmin][+umax][+i]] [ -D[template[+oorig]] ] [ -E[f|l|mstride] ] [
-L ] [ -F[c|n|r|v][refpoint] ] [ -I[tsr] ] [ -Q[~]selection] [ -S[~]”search string” |
-S[~]/regexp/[i] ] [ -T ] [ -V[level] ] [ -aflags ] [ -bbinary ] [ -dnodata ] [ -eregexp ] [ -fflags ]
[ -ggaps ] [ -hheaders ] [ -iflags ] [ -oflags ] [ -sflags ] [ -:[i|o] ]
Note: No space is allowed between the option flag and the associated arguments.
DESCRIPTION
gmtconvert reads its standard input [or input files] and writes out the desired information to standard
output. It can do a combination of nine tasks: (1) convert between binary and ASCII data tables, (2)
paste corresponding records from multiple files horizontally into a single file, (3) extract a subset of
the available columns, (4) only extract segments whose header record matches a text pattern search, (5)
only list segment headers and no data records, (6) extract first and/or last data record for each
segment, (7) reverse the order of items on output, (8) output only ranges of segment numbers, and (9)
output only segments whose record count matches criteria. Input (and hence output) may have multiple
sub-headers, and ASCII tables may have regular headers as well.
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.
-A The records from the input files should be pasted horizontally, not appended vertically [Default].
All files must have the same number of segments and number of rows per segment. Note for binary
input, all the files you want to paste must have the same number of columns (as set with -bi);
ASCII tables can have different number of columns.
-C[+lmin][+umax][+i]
Only output segments whose number of records matches your given criteria: Append +lmin to ensure
all segment must have at least min records to be written to output [0], and append +umax to
ensure all segments must have at most max records to be written [inf]. You may append +i to
invert the selection, i.e., only segments with record counts outside the given range will be
output.
-D[template[+oorig]]
For multiple segment data, dump each segment to a separate output file [Default writes a multiple
segment file to stdout]. Append a format template for the individual file names; this template
must contain a C format specifier that can format an integer argument (the running segment number
across all tables); this is usually %d but could be %08d which gives leading zeros, etc. [Default
is gmtconvert_segment_%d.{txt|bin}, depending on -bo]. Append +oorig to start the numbering from
orig instead of zero. Alternatively, give a template with two C format specifiers and we will
supply the table number and the segment number within the table to build the file name. Append
+otorig/sorig to start the numbering of tables from torig and numbering of segments within a table
from sorig instead of zero. The +o modifier will be stripped off before the template is used.
-E[f|l|mstride]
Only extract the first and last record for each segment of interest [Default extracts all
records]. Optionally, append f or l to only extract the first or last record of each segment,
respectively. Alternatively, append mstride to extract only one out of stride records.
-F[c|n|r|v][refpoint]
Alter the way points are connected (by specifying a scheme) and data are grouped (by specifying a
method). Append one of four line connection schemes: c: Form continuous line segments for each
group [Default]. r: Form line segments from a reference point reset for each group. n: Form
networks of line segments between all points in each group. v: Form vector line segments suitable
for psxy -Sv+s. Optionally, append the one of four segmentation methods to define the group: a:
Ignore all segment headers, i.e., let all points belong to a single group, and set group reference
point to the very first point of the first file. f: Consider all data in each file to be a single
separate group and reset the group reference point to the first point of each group. s: Segment
headers are honored so each segment is a group; the group reference point is reset to the first
point of each incoming segment [Default]. r: Same as s, but the group reference point is reset
after each record to the previous point (this method is only available with the -Fr scheme).
Instead of the codes a|f|s|r you may append the coordinates of a refpoint which will serve as a
fixed external reference point for all groups.
-I[tsr]
Invert the order of items, i.e., output the items in reverse order, starting with the last and
ending up with the first item [Default keeps original order]. Append up to three items that should
be reversed: t will reverse the order of tables, s will reverse the order of segments within each
table, and r will reverse the order of records within each segment [Default].
-L Only output a listing of all segment header records and no data records (requires ASCII data).
-Q[~]selection
Only write segments whose number is included in selection and skip all others. Cannot be used with
-S. The selection syntax is range[,range,…] where each range of items is either a single segment
number or a range with stepped increments given via start[:step:]:stop (step is optional and
defaults to 1). A leading ~ will invert the selection and write all segments but the ones listed.
Instead of a list of ranges, use +ffile to supply a file list with one range per line.
-S[~]”search string” or -S[~]/regexp/[i]
Only output those segments whose header record contains the specified text string. To reverse the
search, i.e., to output segments whose headers do not contain the specified pattern, use -S~.
Should your pattern happen to start with ~ you need to escape this character with a backslash
[Default output all segments]. Cannot be used with -Q. For matching segments based on aspatial
values (via OGR/GMT format), give the search string as varname=value and we will compare value
against the value of varname for each segment. Note: If the features are polygons then a match of
a particular polygon perimeter also means that any associated polygon holes will also be matched.
For matching segment headers against extended regular expressions enclose the expression in
slashes. Append i for case-insensitive matching. For a list of such patterns, give +ffile with
one pattern per line. To give a single pattern starting with +f, escape it with a backslash.
-T Suppress the writing of segment headers on output.
-V[level] (more …)
Select verbosity level [c].
-acol=name[…] (more …)
Set aspatial column associations col=name.
-bi[ncols][t] (more …)
Select native binary input.
-bo[ncols][type] (more …)
Select native binary output. [Default is same as input].
-d[i|o]nodata (more …)
Replace input columns that equal nodata with NaN and do the reverse on output.
-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).
-s[cols][a|r] (more …)
Set handling of NaN records.
-:[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 convert the binary file test.b (single precision) with 4 columns to ASCII:
gmt convert test.b -bi4f > test.dat
To convert the multiple segment ASCII table test.d to a double precision binary file:
gmt convert test.d -bo > test.b
You have an ASCII table with 6 columns and you want to plot column 5 versus column 0. Try
gmt convert table.d -o5,0 | psxy ...
If the file instead is the binary file results.b which has 9 single-precision values per record, we
extract the last column and columns 4-6 and write ASCII with the command
gmt convert results.b -o8,4-6 -bi9s | psxy ...
You want to plot the 2nd column of a 2-column file left.d versus the first column of a file right.d:
gmt convert left.d right.d -A -o1,2 | psxy ...
To extract all segments in the file big_file.d whose headers contain the string “RIDGE AXIS”, try
gmt convert big_file.d -S"RIDGE AXIS" > subset.d
To invert the selection of segments whose headers begin with “profile ” followed by an integer number and
any letter between “g” and “l”, try
gmt convert -S~"/^profile [0-9]+[g-l]$/"
To reverse the order of segments in a file without reversing the order of records within each segment,
try
gmt convert lots_of_segments.txt -Is > last_segment_first.txt
To extract segments 20 to 40 in steps of 2, plus segment 0 in a file, try
gmt convert lots_of_segments.txt -Q0,20:2:40 > my_segments.txt
To extract the attribute ELEVATION from an ogr gmt file like this
# @VGMT1.0 @GPOINT
...
# @NELEVATION|DISPX|DISPY
# @Tdouble|double|double
# FEATURE_DATA
# @D4.945000|-106500.00000000|-32700.00000000
-9.36890245902635 39.367156766570389
do
gmt convert file.gmt -a2=ELEVATION > xyz.dat
or just
gmt convert file.gmt -aELEVATION > xyz.dat
To connect all points in the file sensors.txt with the specified origin at 23.5/19, try
gmt convert sensors.txt -F23.5/19 > lines.txt
To write all segments in the two files A.txt and B.txt to individual files named profile_005000.txt,
profile_005001.txt, etc., where we reset the origin of the sequential numbering from 0 to 5000, try
gmt convert A.txt B.txt -Dprofile_%6.6d.txt+o5000
SEE ALSO
gmt, gmtinfo, gmtselect
COPYRIGHT
2018, P. Wessel, W. H. F. Smith, R. Scharroo, J. Luis, and F. Wobbe
5.4.3 Jan 03, 2018 GMTCONVERT(1gmt)