x_init(1gmt) [debian man page]
X_INIT(1gmt) Generic Mapping Tools X_INIT(1gmt) NAME
x_init - Initialization of Cross-Over Data Bases. SYNOPSIS
x_init -I DESCRIPTION
The purpose of x_init is to create two key files that will be holding all the cross-over information for all the cruises tested. These files are called xx_base.b and xx_legs.b, and they will contain data for each cross-over and totals for each leg, respectively. x_init will create these two files in the current directory, and write out the fileheader with a 1 as the next record number in the case of xx_base.b. NB! Any previous files with the same names in the current directory will be erased, so use with caution. -I Must be present form initialization to take effect. BEWARE
Both files are binary and have fixed record lengths. The formats of the files are as follows: xx_base.b: Record length = 40 bytes. Rec # 1: fileheader Rec # 2: pairheader Next n recs: crossover-structure Rec # n+3: pairheader etc. The fileheader is a 40 byte character string where the last 10 bytes contains the record number of the last record in the file. The pairheader is a 40 byte character string which contains the names of the two legs in question and the number of COEs generated between them. The crossover-structure contains all the information for one COE, that is lat, lon, time along leg values of gravity, magnetics, and bathymetry at the cross-over point, the heading of track #1, and the heading of track #2. See program listing for more details on formats. The file is sequential in that new data are appended at the end of the file. xx_legs.b: Record length = 204 bytes. Each record contains the complete information for each leg that has been checked. The leg-structure contains fields like year of cruise, number of internal/external COEs for gravity, magnetics, and bathymetry, their means and standard deviations, and the best fitting regression lines, i.e. the dc-shifts and drift-rates computed from the time/error data points. See program listing for com- plete description of record format. SEE ALSO
GMT(1), x_system(1) REFERENCES
Wessel, P. XOVER: A Cross-over Error Detector for Track Data, Computers & Geosciences, 15, 333-346. GMT 4.5.7 15 Jul 2011 X_INIT(1gmt)
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X2SYS_BINLIST(1gmt) Generic Mapping Tools X2SYS_BINLIST(1gmt) NAME
x2sys_binlist - Create bin-index files from track data files SYNOPSIS
x2sys_binlist track(s) -TTAG [ -D ] [ -E ] [ -V ] DESCRIPTION
x2sys_binlist reads one or more track data files and produces a multi-segment ASCII track bin-index file (tbf) with the track name in the header and one data record per bin crossed; these records contain lon, lat, index, flags[, dist], where lon, lat are the coordinates of the center of the bin, the index is the 1-D number of the bin, and flags is a bitflag that describes which data fields were available in this bin. The optional dist requires -D. The input files can be of any format, which must be described and passed with the -T option. The bin-index listing is a crude representation of where the track goes and is used by the data archivist to build an x2sys track data base for miscellaneous track queries, such as when needing to determine which tracks should be compared in a crossover analysis. You must run x2ys_init to initialize the tag before you can run the indexing. tracks Can be one or more ASCII, native binary, or COARDS netCDF 1-D data files. To supply the data files via a text file with a list of tracks (one per record), specify the name of the track list after a leading equal-sign (e.g., =tracks.lis). If the names are miss- ing their file extension we will append the suffix specified for this TAG. Track files will be searched for first in the current directory and second in all directories listed in $X2SYS_HOME/TAG/TAG_paths.txt (if it exists). [If $X2SYS_HOME is not set it will default to $GMT_SHAREDIR/x2sys]. (Note: MGD77 files will also be looked for via MGD77_HOME/mgd77_paths.txt and *.gmt files will be searched for via $GMT_SHAREDIR/mgg/gmtfile_paths). -T Specify the x2sys TAG which tracks the attributes of this data type. OPTIONS
No space between the option flag and the associated arguments. -D Calculate the length of trackline segments per bin [Default skips this step]. The length fragments are given as the 5th output col- umn (after the flags). The length units are obtained via the TAB setting (see x2sys_init). -E Convert geographic data to a cylindrical equal-area projection prior to binning. Basically, we apply the projection -JYlon0/37:04:17.166076/360, where lon0 is the mid-longitude of the region. Requires -D, geographical data, and a global region (e.g., -Rg or -Rd). This option is useful for statistics related to trackline density but should not be used when preparing bin- index files for the x2sys track data bases. -V Selects verbose mode, which will send progress reports to stderr [Default runs "silently"]. EXAMPLES
To create a bin index file from the MGD77 file 01030061.mgd77 using the settings associated with the tag MGD77, do x2sys_binlist 01030061.mgd77 -TMGD77 > 01030061.tbf To create a track bin index file of all MGD77+ files residing in the current directory using the settings associated with the tag MGD77+ and calculate track distances, run x2sys_binlist *.nc -TMGD77+ -D > all.tbf SEE ALSO
x2sys_cross(1), x2sys_datalist(1), x2sys_get(1), x2sys_init(1), x2sys_put(1), x2sys_report(1), x2sys_solve(1) GMT 4.5.7 15 Jul 2011 X2SYS_BINLIST(1gmt)