Installing Charts

To install charts OpenCPN must be pointed to a directory containing charts of a recognized format. Don't point OpenCPN to individual charts, you must specify the directory that contains the charts. Download some charts (see below) and organize them in a fashion that suits you.  You may want to consider storing them in a directory where they will not be tampered with or moved accidentaly.
Open the Toolbox by clicking .  You are sent to the first tab "Settings", tick the box "Show Chart Outlines", this will help you visualize the loaded charts.

Then click the tab "Charts".

Under "Available Chart Directories" navigate to your chart-directory. Above we have found the South China Sea vector charts in the /opt/Navigation/ENC directory. When clicking the button "Add Selection" the selected chart directory appears in the box "Active Chart Directories". The screenshots are from Linux, but this process works similar on all platforms. All that remains is to click the "Ok" button. OpenCPN will then process your selection. You can now start using your charts.

A few hints.
  • If all is just black, with maybe some blue lines, you are viewing the background world vector shoreline chart. You must move to the geographical position of the charts you just loaded. As you come close you will see the outlines of your loaded charts, in red for raster charts and in green for S57 vector charts. Click in the rectangle created by the outlines, to activate, and view the chart.
  • When using a vector chart for the first time OpenCPN has to process the data, and transform the information to an internal display format. This can take some time, depending on your computer. This internal SENC chart is then saved for future use.
  • Be aware that it is possible to "Over-zoom" charts in OpenCPN. A warning will appear on the display. Please respect this warning. It is recommended to not zoom more than a factor 2, for safe navigation. You will find the actual zoom-factor in the lower right-hand corner of the display.
  • It is safe and reasonably efficient to put all your charts except  the CM93 database in one large directory, and set that directory in Toolbox->Charts.
    However, if you do a lot of chart downloads, updates, etc., then it will be faster to break the charts folder into smaller groups, and specify them individually in the Toolbox->Charts dialog.
  • The option "Force Full Database Rebuild" is mainly aimed at users converting charts, in a situation where minor changes or corrections are made.
  • OpenCPN, for now, only supports the Mercator chart projection. Charts using other projections will be displayed as if the were Mercator charts. Most charts are using Mercator projection, so this limitation is not to bad.
    Other projections, such as Transverse Mercator or Gnomonic, are mainly used in larger scale charts, for smaller areas, for example harbor plans, in scales larger than 1:50,000.
    The errors introduced in OpenCPN by treating these charts as Mercator are generally small, but be aware of this limitation.

Where to find charts.

  • To get you started quickly, here are three sample charts from Puerto Rico: one, two and three. Right click and use "Save Link As", or similar. Just clicking shows you the actual file as a text file, this is an advanced subject, to be treated later.
  • For those interested in U.S. waters, S57 vector charts are now available for free download from NOAA. Find all the charts you need, both raster (RNC) and ENC's, for your region through NOAA OCS Website at :
  • Links to a wide selection of ENC's for U.S. inland waters and other countries are available at :
  • Brazil publishes free raster charts (RNC) for their whole coast and new charts for inland water is published regularly.There is also coverage for part of Antarctica. Here is a direct link to the download page: Brazilean Charts. Don't miss the link to CARTAS DE RIOS at the bottom of this page.
  • The East Asia Hydrographic Commission is providing free offshore S57 vector charts for the South China Sea area at : .  The motivation for releasing these charts is well worth reading.

    Realizing that official and high quality small scale ENCs conforming with the established IHO standard were not available for the SCS, the EAHC MSs decided to cooperate closely and resolve the situation so that mariners could use most up-to-date chart information for voyage planning and enhancing safety of navigation, rather than resorted to some commercially developed electronic products which were either prepared in proprietary formats, or containing unofficial data with very infrequent updating.

  • Colombia and Australia publishes sample S57 single charts.
  • New Zealand publishes high quality pictures of almost all their charts. There are efforts underway to convert these charts to a format compatible with OpenCPN. This project has moved quickly since the start, in the last few month of 2009.  For the latest on this subject, check the "Chart" thread in the Forum.