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Raster versus Vectorial

Raster-Vectoriel_Web

The official electronic marine charts can only be produced by or under the authority of a government, a certified hydrographic service or any other government institution, the only ones to warranty the quality and the integrity of the data, with an origin authentification, and to insure a regular update. All the other charts types are not official and are called private electronic charts.

The raster and vector charts compatible with the Adrena software come from two private editors : C-Map for the vector charts and Maptech for the raster. The Adrena software are also compatible with the BSB raster charts coming from NOAA and they are delivered with a free worldwide coastline (displayed on C-Map or SHOM data).

Reminder of the regulation :

« The SOLAS Convention includes a requirement for all ships to carry to up to date nautical charts and publications for the intended voyage. This carriage requirement may be satis­fied fully or partly by electronic means. »


Raster charts

The raster chart is a pixelated image done by a numeric scan of a paper chart and then geo referenced. It is the electronic version of a paper chart, a very elaborated “copy” !

Bellow a non-exhaustive raster charts editors list:

  • The NOAA provides on its website with free download the BSB charts covering the coasts and the inland waters of USA.

    couvertureBSB

  • Maptech provides a raster charts catalogue in BSB format. Maptech has copied the marine charts of the bigest hydrographic institutes including all details and colours already present on the paper versions. Maptech is offering more than 4500 scanned charts editated on CD organized by region and including complete charts with bottom heights as well as current data on areas covered by British admiralty and the NOAA. The Maptech charts are distributes on CR-ROM and have to be registred to be used.

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  • MAPMEDIA is a private format, only compatible with the Maxsea navigation software.

     

     

    Advantage :

    • Exact reproduction of the paper charts : as far as the chart is up to date, it is sure that all the paper chart elements will figure on the electronic chart.
    • The users are used to the paper charts graphics and to its symbols.
    • Easy to be read.
    • Reliability : a true color copy of official paper charts coming from Hydrographic services.
    • Information always available on the screen.

       

      Inconvenient :

      • Pixilation on over zoom.
      • Chart loaded when zooming so reading is less clear.
      • They take more space on your disk and usually they are longer to be loaded.
      • A Maptech license is linked to a computer and allows two unlock keys/PC maximum.

       

      Vector charts

      The verctor chart is an individual numeric description of each objet coming from a paper chart and of the links between those objects. A vector chart is organized with layers, so it is easy to only display the wanted information ( hide the lights if sailing during the day, hide the depth when sailing offshore,…).

      Below a non-exhaustive list of vector charts editors :

      • C-Map that provides vector electronic charts with a worldwide coverage. There are sold with three coverage sizes : MAX Local, MAX Wide & MAX Megawide. The charts are automatically loaded on the screen with the best chart available and with an adapted resolution zoom. The details are displayed more and more precisely when zooming on an area.

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      • Navionics that provides worldwide electronic chart folio. It is a private cartography distributed on CF-Card and SD-Card.

       

      Advantage :

      • The zoom function (in&out) does not modify the dimension of the elements displayed on the chart (names, marks, etc…), so the texts have always an optimum size.
      • High precision : some vector chart are able to get a two cm precision on earth.
      • Some additional informations can be stored directly in the data, so they are easy to read when zooming in.
      • Côté dynamique : possibilité de paramétrer les cartes et de filtrer les données donc plus lisible lorsqu’on zoome.
      • The vector charts take less space on the disk and are generally faster to load.
      • The C-Map MAX chart are linked to Adrena’s dongle, so you can use the charts on each computer you use with Adrena.

       

      Inconvenient :

      • The vector chart look is not always very nice, even if they are more usefull.
      • The chart composition with different scales cells is not very convenient.
      • With the progressive display of the object according to the zoom, it is possible to miss something when zoom is not large enough. Happens also with raster (on 1/100 000 for example).
      • Even if the charts data come directly for the hydrographic institutes, they are yet recaptured by the private editor. So it is not absolutely certain that all the paper chart details have been captured.

       

      The choice of the kind of chart to embark on board stays really personal, it depends of the use and of the habits of everyone, so raster or vector, it is your turn to choose !