The CM93 v2 data structure is designed for efficient storage and retrieval. The folders named with eight-digit numbers represent specific geographic tiles. Advanced users can even parse these charts programmatically. For developers interested in working with CM93 v2 data programmatically, a Node.js tool called node-cm93 is available on GitHub. It can read and decode sea chart data files, convert coordinates from tile XY coordinates to longitude and latitude, and output GeoJson for vector rendering.
OpenCPN handles CM93 v2 charts exceptionally well, allowing for seamless integration alongside official charts. Step 1: Prepare the Chart Files Download the CM93 v2 dataset. Unzip/extract the files.
Click the button. Navigate to the folder where you stored your CM93 v2 charts and select it. When you press the "Add Directory" button, OpenCPN defaults to "My Documents" on Windows or the user's home directory on Linux and Mac. These are good places to keep your charts. cm93 v2 charts download install
A typical usage example:
Understanding the file structure is helpful for successful installation: The CM93 v2 data structure is designed for
This distinction is crucial. CM93 v3 charts are fully compliant with the IHO S-57 Edition 3.0 standard and support automatic updates. Importantly, most open-source chart plotting software—including OpenCPN—does not support CM93 v3, which remains a proprietary format requiring specific license keys. For users of free and open-source navigation tools, CM93 v2 remains the more practical choice despite being discontinued and increasingly dated.
Ensure the subfolders (the numbered directories) are directly inside this main folder. Step 2: Add the Directory to OpenCPN Launch . For developers interested in working with CM93 v2
: Zoom in closely to the area. Vector charts dynamically hide information when zoomed out too far to prevent screen clutter.
| Source | Quality | Update Frequency | Cost | Use Case | | :--- | :--- | :--- | :--- | :--- | | | Fair/Outdated | Never (2013) | Free (community) | Ocean passage planning, backup | | OE SENC (o-charts) | Very High | Monthly | $35–150/year | Official vector charts (EU, US) | | Satellite imagery (SAS.Planet) | High | 2020–2025 | Free | Anchoring, reef spotting | | RNC Raster (NOAA) | Good | Weekly | Free (USA only) | US coastal navigation |
This guide focuses primarily on installing CM93 v2 charts in , the most popular open-source chart plotting software. However, the principles apply to other software with minor variations.
The CM93 v2 data structure is designed for efficient storage and retrieval. The folders named with eight-digit numbers represent specific geographic tiles. Advanced users can even parse these charts programmatically. For developers interested in working with CM93 v2 data programmatically, a Node.js tool called node-cm93 is available on GitHub. It can read and decode sea chart data files, convert coordinates from tile XY coordinates to longitude and latitude, and output GeoJson for vector rendering.
OpenCPN handles CM93 v2 charts exceptionally well, allowing for seamless integration alongside official charts. Step 1: Prepare the Chart Files Download the CM93 v2 dataset. Unzip/extract the files.
Click the button. Navigate to the folder where you stored your CM93 v2 charts and select it. When you press the "Add Directory" button, OpenCPN defaults to "My Documents" on Windows or the user's home directory on Linux and Mac. These are good places to keep your charts.
A typical usage example:
Understanding the file structure is helpful for successful installation:
This distinction is crucial. CM93 v3 charts are fully compliant with the IHO S-57 Edition 3.0 standard and support automatic updates. Importantly, most open-source chart plotting software—including OpenCPN—does not support CM93 v3, which remains a proprietary format requiring specific license keys. For users of free and open-source navigation tools, CM93 v2 remains the more practical choice despite being discontinued and increasingly dated.
Ensure the subfolders (the numbered directories) are directly inside this main folder. Step 2: Add the Directory to OpenCPN Launch .
: Zoom in closely to the area. Vector charts dynamically hide information when zoomed out too far to prevent screen clutter.
| Source | Quality | Update Frequency | Cost | Use Case | | :--- | :--- | :--- | :--- | :--- | | | Fair/Outdated | Never (2013) | Free (community) | Ocean passage planning, backup | | OE SENC (o-charts) | Very High | Monthly | $35–150/year | Official vector charts (EU, US) | | Satellite imagery (SAS.Planet) | High | 2020–2025 | Free | Anchoring, reef spotting | | RNC Raster (NOAA) | Good | Weekly | Free (USA only) | US coastal navigation |
This guide focuses primarily on installing CM93 v2 charts in , the most popular open-source chart plotting software. However, the principles apply to other software with minor variations.