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Diffstat (limited to 'misc/xtide/DESCR')
| -rw-r--r-- | misc/xtide/DESCR | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/misc/xtide/DESCR b/misc/xtide/DESCR new file mode 100644 index 00000000000..eb0fa009b0b --- /dev/null +++ b/misc/xtide/DESCR @@ -0,0 +1,24 @@ +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). + +The algorithm that XTide uses to predict tides is the one used by the +National Ocean Service in the U.S. It is significantly more accurate +than the simple tide clocks that can be bought in novelty stores. +However, it takes more to predict tides accurately than just a spiffy +algorithm -- you also need some special data for each and every +location for which you want to predict tides. XTide reads this data +from harmonics files. Ultimately, XTide's predictions can only be as +good as the available harmonics data. Due to issues of data +availability and of compatibility with non-U.S. tide systems, the +predictions for U.S. locations tend to be a lot better on average +than those for locations outside of the U.S. +* Deviations of 1 minute from official predictions are typical for U.S. + locations having the latest data. +* Deviations of 20 minutes are typical for non-U.S. locations or U.S. + locations that are using obsolete data. +* Much longer deviations indicate a problem. |