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XTide 2.12.1
XTide 2.12.1 fixes a bug that caused some SVG outputs to fail. Get
the final release from http://www.flaterco.com/xtide/files.html#xtide.
tideEditor 1.4.2
tideEditor has finally been migrated from Qt 3 to Qt 4. Available
from http://www.flaterco.com/xtide/files.html#extras.
Mailing list
There is a manually-maintained, announce-only mailing list to which
I send notices of each update to XTide or the harmonics data.
You can request to join by e-mailing me at dave@flaterco.com.
Please note: If an announcement to you gets bounced by your
mail server, you fall off the list. Some long-time contributors
have fallen off because, unbeknownst to them, their ISPs subscribed to
a spam blackholing service that blackholed all pair.com-hosted domains
after one of them sent out spam.
Roadmap to future development
Things worth fixing / TO-DO list
Data maintenance
I refresh the data for the U.S. once a year from the National Ocean
Service web site. This is a lot of work and takes up basically all
of the time and energy that I can devote to data maintenance.
The coverage of other countries suffered a major blow in 2001 when the UKHO claimed to own the copyright on tons of old tide
data that I had painstakingly processed for XTide. With the help of
some diligent volunteers, I eventually managed to source new data for the
U.K., Germany [*], Netherlands, and Canada.
Since then, a slowly growing group of countries has made harmonic constants
or water level records available on the web. However, the legal terms
attached to those data seldom address distribution of derivative works though
commercial channels such as packaged Linux distributions, and scraping data
off of web sites is inherently laborious.
I encourage those tide authorities that are now making harmonic constants
publicly available on their web sites to package those data using the open
source tools available from http://www.flaterco.com/xtide/files.html and distribute
those data in TCD files. Failing that, any qualified volunteers who
wish to maintain a harmonics database for their own countries may begin by
clarifying the terms of use for the relevant data with their local tide
authorities and then download the tools and go do it. Following is a
list of the data sources that have been brought to my attention. If you
succeed, let me know and I'll link to your download site. [**]
- Canada (I only processed the active stations; there are hundreds of old, inactive ones)
- Italy
- Norway
- Spain
- U.K. (I processed these data once but would gladly hand off the maintenance task to someone local.)
- Miscellaneous
* The German data were supplied as a rather short
time series of water level observations from which I derived harmonic
constants. The agreement with official predictions was never
that hot. Further investigation by Jan Deepen in 2009 revealed
significant, uncorrectable differences with authoritative predictions,
so the German data were retired from the database at the end of
2009.
** Since a large part of the issue here is legal ambiguities, it would be preferable for you to retain control over your files on a server in your own country, where any copyright disputes might be resolved in a civilized fashion.
xtide
- Test patch for using Xaw3dxft
- Renovate to use the latest fad widget toolkit, use scalable graphics
everywhere, play nice with modern desktop environments.
- Unbundle Dstr?
harmgen
libtcd
- Things not to do unless/until a major revision is needed.
- Get rid of internal state; fix inability to have more than one database
open
- Remove gratuitous complexity in the encoding of speeds, equilibrium
arguments, and node factors; make speeds 32-bit unsigned with no
offset
- Possibly permit node factors to be specified for intervals shorter than
1 year and/or support apps that use libcongen to generate the
node factors themselves
Suggested XTide features and other etceteras
The following features have been suggested or thought about but did
not make the cut. They could be added in future revisions if
there were sufficient demand.
- There ought to be a way to specify relative dates and times in the
–b and –e fields. Need an applicable standard; ISO
8601 doesn't support it. Simon Bridger requested –b and
–e to recognize relative specifications like yesterday, today,
tomorrow, mon–sun, sat+7 for next Saturday, "tomorrow 23:59" or
"sat 00:00". Others want to specify a small relative offset
from the current time for –b to change the position of the +
mark in graphs.
- Factor out a standalone component library as a favor to developers
who want to reuse XTide's engine but reinvent its wheels.
- Generate maps for xttpd navigation and general
illustration, include in LaTeX form.
- Graeme Rae suggested a line for the current time in text
listings, like "2001-03-19 11:50 AM PST 0.10 feet Falling." This
is doable now that the tide events code has been refactored, but it's
not clear what the settings and behaviors should be to handle the
"now" event consistently across all modes. Graphs and clocks
have their own ways of showing the "now," and it would be
inappropriate to include "now" in a calendar.
- Simon Bridger requested support for multiple –b and –e
specifications.
- Tim Cera notes that Options might be more user-friendly if it was
split into separate menus for "Create new windows" versus "Change settings."
- Add a real color chooser in control panel. This would come
free with Qt or similar if we ever migrated from Athena widgets.
- Constituent inference was patched in via libtcd and maybe could have
been integrated better. In theory, you might want to control it
on a station-by-station basis like preferred units.
But, maybe it's a non-issue. Nobody has complained yet.
- Generate node factors and equilibrium arguments more than once a
year. Most tide prediction software does it monthly or at least
does it for the middle of your prediction interval. But the
legacy of SP98 is to do it yearly.
- Add support for Doodson style tide prediction as used by
Foreman's IOS package. At this time there seems to be little benefit
to be gained by doing this:
- No new Doodson data appear to be forthcoming.
- Most Doodson constituents are approximated fairly well by Congen now.
- The ones that aren't approximated well are those that are
drastically affected by latitude. To support latitude-dependent
constituents, node factors and equilibrium arguments would have to be
generated internally to XTide, which would be a significant
architectural change.
- Casement opined that the
latitude-dependent method is bogus anyway because tides are generated some
place in mid-ocean with a different latitude.
- If you want IOS, you can find it at http://www.pac.dfo-mpo.gc.ca/sci/osap/projects/tidpack/tidpack_e.htm.
- Simon Bridger requested a "weekend warrior" option that
lists today, tomorrow, Saturday, Sunday, and next Saturday.
- Jef Poskanzer long ago asked for a global plot of tide
levels to show how the tides move around. This could be done by
color-coding the
dots on the globe, but it would (1) require a true-color display and
(2) be too slow to be the default behavior of the globe. Hans Bot has
seconded this request.
- David Mendez suggests plotting the derivative of the tide as well as the tide—this is useful for predicting swells.
- Diane Grant wants to be able
to execute a query like 'find all days in this year having a
flood greater than 3.0 between 8 AM and 9 AM.'
- xttpd: Change mapping of locations to URLs so that links won't break when
harmonics files are changed. Thought about this but could not find
a better solution than putting the entire location name in the URL, which
is already semi-supported by the exact query feature.
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