After adding the directory, click . OpenCPN will automatically scan the directory for recognized chart formats. Because CM93 v2 charts are structured in folders, the scanning process may take several minutes if the entire world database is large. You should see progress indicators showing the chart files being processed. Once the scan is complete, close the Options dialog.
Marine navigation requires accurate, up-to-date, and reliable electronic navigational charts (ENCs). While modern vector and raster charts are standard, the format remains a popular, albeit legacy, choice for many cruisers using open-source chartplotters like OpenCPN .
If you only see .A , .B , .C files but no .DAT files, the dataset is incomplete.
: A complete worldwide dataset features up to 144 subdirectories mathematically named from 00300000 to 04501020 . cm93 v2 charts download install
Because CM93 v2 is a heavy dataset, it is recommended to keep it on a fast drive, such as an SSD, for quicker zooming and panning. Summary of Best Practices Description Download Seek reliable community sources (forums). Location
OpenCPN will automatically highlight shallow areas in a distinct blue shading, warning you of potential grounding hazards. Troubleshooting Common Installation Issues Issue 1: "No charts visible" or "Only red outlines show up"
Q: What is the difference between CM93 V2 charts and other chart types? A: CM93 V2 charts are a type of electronic chart that provides detailed and accurate navigation data, whereas other chart types, such as raster charts, may not offer the same level of detail and accuracy. After adding the directory, click
You must ensure you are using . Later C-MAP editions—such as CM93 Version 3 (v3)—utilize proprietary, pre-processed SENC encryption layers. Programs like OpenCPN do not support v3. If your chart root folder is missing the .EXD validation file and does not follow the 144-folder grid structure, you likely have an incompatible v3 directory. 2. CM93 v2 Charts: Download Considerations
node node-cm93/bin/app.js scan -i cm93files/ -o cm93json/ -id 02100420,01500420
A complete global CM93 v2 dataset can be quite large. For users who only need specific regions, it is possible to work with partial datasets. OpenCPN explicitly supports partial CM93 datasets covering only one or a few geographical regions, which can significantly reduce storage and processing requirements. You should see progress indicators showing the chart
I can provide customized advice on how to acquire official local charts to pair alongside your system. Share public link
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 .
Zoom in on a coastal area to verify that charts are displaying properly. You should see chart outlines in green or blue squares. If you do not see charts, you may need to adjust your zoom level—CM93 charts often appear only when you zoom in sufficiently on a specific area. To verify that the charts are accepted, you should see green squares in place of charts. You must zoom on square-marked charts until you see the actual chart details appear.
Browse your system to locate and select your root CM93_v2 folder, then click . Ensure the box next to your new chart path is checked.
For serious offshore cruising, paper charts remain the ultimate backup in case of electronic failure.