---
name: "x_update"
section: "1gmt"
platform: "linux"
package: "gmt"
version: "4.5.12-1"
release: "Debian 8 (Jessie)"
platforms: ["linux"]
url: "https://new.carta.tech/x_update"
---

# x\_update(1gmt)

Archiving of Cross-Over Information

## NAME

**x\_update** - Archiving of Cross-Over Information

## SYNOPSIS

**x\_update** *cross-overfile* \[ **-X***xbase* \] \[ **-L***legbase* \]  \[ **-V** \] \[ **-W***max* \]

## DESCRIPTION

**x\_update** reads the ASCII file produced by **x\_over** and writes the information to the database files *xx\_base.b* and *xx\_legs.b* (unless other filenames are specified on the command line) using a compact, binary format. The options recognized are:

- **-X**

  Indicate alternate *xx\_base.b* file.

- **-L**

  Indicate alternate *xx\_legs.b* file.

- **-V**

  Selects verbose mode, which will send progress reports to stderr \[Default runs "silently"\]. Reports the pair currently being processed.

- **-W**

  Prints a warning if the number of COEs generated by any pair of legs exceed *max*.

## BEWARE

For security reasons the *xx\_legs.b* are first renamed to *xx\_legs.b\_old*, to prevent loss of information if a black-out or system crash should occur during writing of the new *xx\_legs.b* file. It is recommended that the old file is left on the disk in case of other disasters. Note that **x\_update** does not check if a pair of legs already exist in the *xx\_base.b* file. It is the user's responsibility to ensure that duplication of information does not occur. Should some pairs already in the database need to be re-examined, then run **x\_remove** which will wipe out all traces of the specified cruises from the x\_system data base files. Now we can pass the pairs that need to be redone through **x\_over/x\_update** again.

## SEE ALSO

[*GMT*(1)](/GMT/1.md), *x\_system*(1)

## REFERENCES

Wessel, P. XOVER: A Cross-over Error Detector for Track Data, *Computers & Geosciences, 15*, 333-346.