Inside each folder, you will typically see subfolders labeled with letters like B , D , F , or G , which correspond to scale layers. The files inside these folders have extensions such as .G for general chart data, .D for depth data, .B for buoy data, and various other extensions for different feature types.
The OpenCPN project—and virtually all responsible navigational authorities—explicitly warns against using pirated copies of CM93 v2 charts for active navigation. According to the official OpenCPN documentation, CM93 is an old chart format originally used by C-Map. Unauthorized copies of these charts are widely available on the Internet, but these charts are no longer maintained, are out of date, and are of dubious providence. Consequently, they are .
OpenCPN and CM93 v2 have a long and intertwined history. OpenCPN was one of the first open-source chart plotters to implement robust CM93 v2 support, and the format remains a major reason many sailors choose OpenCPN to this day. cm93 v2 charts download install
CM93 v2 charts are worldwide vector charts originally created by C-MAP. While newer formats like CM93 v3 exist, the version 2 format remains widely popular because it uses an open structure that is directly compatible with free navigation software like OpenCPN. Key Features
Now that you have the chart folder on your hard drive, "installation" is just telling your chart plotter software where to look. Inside each folder, you will typically see subfolders
Before adding charts, organize your chart files. The recommended approach is to create a master directory for your charts, with subdirectories for different chart types. For example, create a folder called Charts on your hard drive, and inside it, create subfolders such as RNC for raster charts, ENC for official S57 charts, and CM93 for your CM93 v2 charts. Place your entire CM93 v2 chart database folder (the one containing CM93ATTR.DIC and all the 003xxxxx folders) inside this CM93 subfolder.
You can create specific Chart Groups, allowing you to quickly switch between your official S-57 charts and your CM93 v2 charts. According to the official OpenCPN documentation, CM93 is
If the charts are installed correctly, you will see detailed vector data.
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