KAP File

What are KAP files and how to open them

Are you having problems opening a KAP file or are you simply curious about its contents? We're here to explain the properties of these files and provide you with software that can open or handle your KAP files.

What is a KAP file?

A .KAP file is a MapInfo Sea Chart file.

MapInfo Sea Chart (.KAP) files store scanned nautical charts as raster images along with embedded georeferencing information that ties points on the image to real-world latitude and longitude coordinates. These charts are made using the MapInfo Sea Chart format (also known as BSB/KAP), originally defined by Maptech (formerly Nautical Technologies Inc.), and are still produced for maritime navigation, chart plotting, and offshore route planning. The imagery uses limited color palettes and includes metadata like chart scale, projection, datum, date, and control points so that navigation software or chartplotters can overlay GPS-based position accurately.

MapInfo (Pitney Bowes Software Inc.) is the vendor that writes these files when producing official raster nautical charts. Once produced, a .KAP file can be used by navigation programs that display raster navigational charts, including OpenCPN. Some .KAP charts come alongside a .BSB descriptor file that groups multiple .KAP panels as part of a larger chart set, but the .KAP file on its own contains image and georeferencing data sufficient for display.

Inside each .KAP file there is a plain‐text header section with tags like "VER" (format version), "REF" (control points), "RGB" (color palette entries)), "PR" (projection), and "GD" (geodetic datum), followed by a binary raster image encoded with palette‐indexed scanlines. One identifier is that the file begins with the byte 0x21 ('!'), and contains the strings "VER", "RGB", and "IFM". The header is terminated by a Control-Z/NUL sequence.

How to open KAP files

We have identified one KAP opener that is compatible with this specific type of KAP file.

Programs that open MapInfo Sea Chart files

Last updated: August 7, 2026

Various apps that use files with this extension

These apps are known to open certain types of KAP files. Remember, different programs may use KAP files for different purposes, so you may need to try out a few of them to be able to open your specific file.

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