XTide is a package that provides tide and current predictions in a wide
variety of formats. Graphs, text listings, and calendars can be generated,
or a tide clock can be provided on your desktop.
XTide can work with X-windows, plain text terminals, or the web. This is
accomplished with three separate programs: the interactive interface
(xtide), the non-interactive or command line interface
(tide), and the web interface (xttpd).
is an XTide web server. It provides web-based access to XTide's tide
predictions by allowing a web browser to speak directly to the XTide
program in HTTP.
or it can co-exist with one.
If you run
with no command line arguments, it will assume that it is
and try to bind port 80. If you want it to co-exist with an
existing server, or if you do not have privilege to get port 80, give it
the port number as the first command line argument:
If you need to specify both address and port number, separate the two
with a slash, like this:
% xttpd 127.0.0.2/8080
Once the port is established,
will try to set its UID and GID to values that were specified at
compile time. If it is unable to do this, it will log failure
messages to syslog and then exit. Consequently, if it is to be
started by someone other than root, that user's UID and GID must be
configured at compile time. Instructions for doing this are available
For a complete
discussion of the command line options and a detailed explanation of the
XTide package, please see the verbose documentation at
Unless a configuration file
is supplied, you must set the environment variable
to point to the harmonics
files that should have been installed along with the
If a configuration file is used, the first line should consist of the
colon-separated list of harmonics files (e.g. the
line above without the "export HFILE_PATH=" part).
The environment variable takes precedence over the configuration file.
CONFIGURATION ON DEBIAN SYSTEMS
systems the web server
may optionally be started at boot time by editing
variable and uncommenting out the line). Set the environment variable
to change the mail feedback address.
Also, note that on Debian systems the tidal harmonics data file are stored in
as used above.
Daytime background color in tide graphs (default SkyBlue).
Color of datum line in tide graphs (default white).
style format string for printing dates (default %Y-%m-%d).
Foreground in tide graphs during outgoing tide (default SeaGreen).
Select whether or not to draw datum and middle-level lines in tide graphs
Events to suppress (p = phase of moon, S = sunrise, s = sunset, M = moonrise, m
= moonset), or x to suppress none. E.g, to suppress all sun and moon events,
set eventmask to the value pSsMm.
Foreground in tide graphs during incoming tide (default Blue).
Color of text and other notations (default black).
Aspect for tide graphs (default 1.0). This
controls not the width or height of the window but rather the relative scaling
of the X and Y axes in the plot of the tide curve.
Height for tide graphs (default 312 pixels).
Select whether or not to label tenths of units in tide graphs
Width for tide graphs (default 960 pixels).
style format string for printing hour labels on time axis (default %l).
Select whether or not to use inferred values for some constituents (default n).
For expert use only.
Width for lines in tide graphs with
(default 2.5 pixels).
Color of mark line in graphs (default red).
Color of middle-level line in tide graphs (default yellow).
Nighttime background color in tide graphs (default DeepSkyBlue).
Select whether or not to draw tide graphs as line graphs
style format string for printing times (default %l:%M %p %Z).
Select whether or not to draw depth lines on top of the tide graph
Preferred units of length (default no preference).
Print version string and exit.
Select whether or not to coerce all time zones to UTC (default n).