aismmfile-cpp

Reader for the "positional AIS memory mapped file" format, originally implemented in aismmfile.

This (binary) format offers fast and easy to use access to positional AIS data, in a portable, cross-language manner.

See the original project for details of the format, and a program to generate files. We also have a Java reader and writer implementation in the works.

This project exposes a single file header only C++ library, with no dependencies outside the standard library, and a pair of utility programs to investigate and read aismmfile files.

Currently the library and programs only compile on POSIX, as we haven't yet included a Windows mmap wrapper, but that's pretty easy to add if anyone is interested.

C++ library - aismmfile.hpp

Just add include/ to your include path to use this, or copy include/aismmfile.hpp to your project directory.

Allows zero-copy access to per-mmsi track message data, exposed as arrays of structs.

Example:

// #include <aismmfile.hpp>

auto mmf = aismmf::AISMmFile {"path/to/file"};

if (mmf.hasMmsi (12345)) {
    auto track = mmf.mmsi (12345);
    std::cout << track.size() << std::endl;  // number of messages in track

    // Iterate over contiguous array of aismmf::AisMsg structs
    for (auto msg : track) {
        std::cout << msg.mmsi   << "," << msg.timestamp << ","
                  << msg.lat    << "," << msg.lon       << ","
                  << msg.course << "," << msg.speed
                  << "\n";
    }
}

Helper programs

Use these to look inside aismmf files without having to write any code.

aismmfile_ls

USAGE:
  aismmfile_ls FILE.aismmf
Prints a CSV of the MMSIs and per-MMSI counts in the file to stdout.
Also writes the total number of messages and MMSIs to stderr.

aismmfile_mmsi

USAGE:
  aismmfile_mmsi FILE.aismmf MMSI
Prints a CSV containing all the messages stored for MMSI
in FILE to stdout.
Also prints the total number of messages to stderr.

System install

Call make && sudo make install in the usual way.

By default installs to /usr/local; specify an alternative path prefix as follows: sudo make PREFIX=/my/other/prefix install

Self tests

Run make run-tests to build and run the test runner, which uses the pre-made file test/testdata.aismmf. It informs on success or failure.

Copyright and license

Project copyright (c) 2018 Inkblot Software Limited.

Licensed under the terms of the Mozilla Public License v2.0. This means you can permissively use this library in your own (perhaps proprietary) projects, but any changes you make to this project's files stay open.