Before downloading CM93 v2 charts, it is important to ensure that your navigation software supports the format. Here are some of the most popular options:
Official marine navigation authorities universally recommend using authorized, up-to-date, official chart products for navigation. Free and community-distributed chart sets should only be used for planning, education, or as a backup reference, never as a primary source for navigation in unfamiliar or hazardous waters.
This scans the specified folders and outputs a GeoJSON file showing the location polygons of each chart file.
For harbor entrances, reef passages, and any area with recent changes, verify chart information with official Notices to Mariners or up-to-date ENC charts.
Unlike official S57 or encrypted S63 Electronic Navigational Charts (ENCs), CM93 version 2 operates on a specific database architecture. The File Structure
While CM93 v2 charts are incredibly useful for situational awareness, passage planning, and general cruising, they are a legacy product.
CM93 is a vector chart format originally created by C-Map (now owned by Jeppesen) for electronic charting systems. The version 2 (v2/ED2) iteration represents the final free—albeit unofficial—distribution widely available online.
A robust navigation strategy should include at least two independent chart sources (for example, updated NOAA ENC charts plus official S63 charts). This provides redundancy and allows cross-referencing.
Go to and adjust the following:
Before downloading CM93 v2 charts, it is important to ensure that your navigation software supports the format. Here are some of the most popular options:
Official marine navigation authorities universally recommend using authorized, up-to-date, official chart products for navigation. Free and community-distributed chart sets should only be used for planning, education, or as a backup reference, never as a primary source for navigation in unfamiliar or hazardous waters.
This scans the specified folders and outputs a GeoJSON file showing the location polygons of each chart file.
For harbor entrances, reef passages, and any area with recent changes, verify chart information with official Notices to Mariners or up-to-date ENC charts.
Unlike official S57 or encrypted S63 Electronic Navigational Charts (ENCs), CM93 version 2 operates on a specific database architecture. The File Structure
While CM93 v2 charts are incredibly useful for situational awareness, passage planning, and general cruising, they are a legacy product.
CM93 is a vector chart format originally created by C-Map (now owned by Jeppesen) for electronic charting systems. The version 2 (v2/ED2) iteration represents the final free—albeit unofficial—distribution widely available online.
A robust navigation strategy should include at least two independent chart sources (for example, updated NOAA ENC charts plus official S63 charts). This provides redundancy and allows cross-referencing.
Go to and adjust the following:
