October 10, 2007 10:34
I do take your point about interpolation not being as accurate as the properly modelled tidal charts available from the official HOs. However the fact remains that a significant number of PC-based marine charting applications are able to provide tidal vectors. This means that..
(a) they're using a dataset similar to Mr Tides and interpolating it or
(b) they're plotting vectors from more detailed data than is available in the Xtide harmonics database.
Some cartography (certainly Maptech's BSB charts, and I believe some S57 charts) include additional information about the tidal vectors in the area that they cover.
So maybe this is a question that needs to be addressed by the charting software...
(a) they're using a dataset similar to Mr Tides and interpolating it or
(b) they're plotting vectors from more detailed data than is available in the Xtide harmonics database.
Some cartography (certainly Maptech's BSB charts, and I believe some S57 charts) include additional information about the tidal vectors in the area that they cover.
So maybe this is a question that needs to be addressed by the charting software...
Never knowingly overcanvassed!