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    Updating of Electronic Charts
    From: Philip Ouvry
    Date: 2000 May 22, 5:08 PM

    There is a problem which has been bugging me for sometime now.   Paper charts
    have been developed into raster electronic charts and will ultimately become
    vector electronic charts.   With a vector chart there can be up to 40 layers of
    information.   The navigational information thereon can be presented and
    interpreted in a multitude of ways.
    However close examination of paper charts often shows large areas marked, for
    example,  or .   Essentially the
    data on which the chart is based is often sketchy or non-existent.
    Most national hydrographic authorities have few resources available to conduct
    surveys of non-essential areas.   In the United Kingdom the Royal Institute of
    Navigation encouraged Yacht Clubs and local groups to conduct  
    which were detailed surveys of local navigable creeks and anchorages for which
    no accurate charts existed.   However their results were not accepted for
    inclusion on nationally available charts.
    The same problem exists for sailing directions or pilots.
    With GPS and electronic charts the temptation will be to explore more small
    estuaries and potential anchorages.   It makes sense that every time a new place
    is explored by a conscientious navigator, his results should be entered in a
    database from which, either on a national or local basis, an increasingly
    accurate series of electronic charts can be produced.   These could be simply
    downloaded onto a navigators onboard computer.   They could also be supported by
    a  service.
    In the United Kingdom the Cruising Association produce a Handbook which is
    continually updated by the 6000 members and regularly reprinted.   It would seem
    to be a good idea for all yacht clubs, cruising associations and long-distance
    navigators to gather navigational data which could be fed into a central
    database from which more detailed and accurate electronic charts could be
    Has anybody any comments?
    Philip Ouvry

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