Two Magical Things

Thing One:       GPSU
Without this splendid program and the excellent personal back-up from Alan Murphy this project could never have got under way. If you need to convert one or two  of your own tracks to another format I will happily do it for you but if you have a larger amount of file conversion/editing to do please go to Alan's site

Thing Two:  Google Earth 
When I started planning this Library I intended only to include GPX and PTF file formats for download. Then, because GPSU offered the possibility I tried a few of Bluesipp's tracks on GE.
In almost all cases this gives a quite wonderful aerial view of the anchorages and a record of just how we managed to get in and out.  (Plus, if you want them, plenty of pictures of what had seemed a remote and seldom visited spot!) So even if you don't want the tracks for your navigation program the views of  the anchorages and harbours could be very helpful.

But a MAJOR added advantage revealed itself as I checked  anchorages and reef passages before including them in the Library.  Very occasionally a track seemed to go over a hazard - or even over solid ground. I thought perhaps Google had got it wrong. I checked one of  the puzzling tracks on an electronic chart and all appeared to be well. So indeed Google seemed to be wrong.
Then I checked the track itself rather more carefully and found a sudden half mile sideways jump. (and later a jump the other way)
The navigator had discovered that his local chart (the same as mine) was "wrong", i.e. did not agree with his GPS set to WGS84 .  This made the chart useless if he was to use it with his GPS for inshore pilotage. One solution was to shift his GPS datum until his vessel was shown sitting in the right place on the electronic chart. Then he could use his chart within the local cruising area and fix his position on it with his GPS.  Entirely sensible.   But for navigators planning an approach to those anchorages the track that he laid down with his re-set GPS is misleading or even dangerous unless they know the offset he used.
So now I include a KMZ  (Google Earth) version of every track.   I have devised a way of detecting these shifts and try very hard to avoid including shifted tracks in the Library but cannot of course offer any guarantee.

Thing Two and a half
And actually Google Maps is pretty amazing too but I wish it got on a little better with its          cousin/brother/sister/uncle/no-connection-with-the-firm-next-door (GE). However, with that reservation, the facilities Google Maps offer free to the world at large are quite remarkable and this site is built around them.
I spoke far far too soon - having based the indexing system on Google Maps and put in rather a lot of work over the last four years Google has now scuppered the entire project by removing virtually all the tools I need and will shortly remove my existing sketched maps as well.

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