Introduction

Library for decoding maritime Automatic Identification System messages. Forked from original POSIX-oriented version to optimize for embedded platforms as much as possible, starting with removal of all c++ <ostream> dependencies (severe code bloat).

See Also

Automatic Identification System

Other open source AIS projects:

• GPSd
• AisLib
• noaadata
• ais-areanotice
• OpenCPN
• aisparser
• nmea_plus

Building

Building with Python

$ python setup.py build
$ python setup.py install

Testing with Python

$ virtualenv ve
$ source ve/bin/activate
$ python setup.py test

Building with CMake

$ cmake .
$ make

Building with legacy Makefile

$ make -f Makefile-custom test

Usage

There are two interfaces to libais, one high-level iterator based one and a low-level fast C++ only one. The iterator based interface is accessed the following way:

import ais.stream
with open("file.nmea") as f:
    for msg in ais.stream.decode(f):
        print msg

To use the low-level C++ interface directly, you need to handle multi-line messages and padding yourself:

import ais
ais.decode('15PIIv7P00D5i9HNn2Q3G?wB0t0I', 0)
ais.decode('402u=TiuaA000r5UJ`H4`?7000S:', 0)
ais.decode('55NBjP01mtGIL@CW;SM<D60P5Ld000000000000P0`<3557l0<50@kk@K5h@00000000000', 2)

There is also support for converting parsed messages to the structure output by GPSD / gpsdecode. For full compatibility, you have to write the resulting message dictionaries to a file with json.dump() and add a newline after each message.

import ais.stream
import json
import ais.compatibility.gpsd

with open("infile.nmea") as inf:
    with open("outfile.gpsd") as outf:
        for msg in ais.stream.decode(f):
            gpsdmsg = ais.compatibility.gpsd.mangle(msg)
            json.dump(gpsdmsg, outf)
            outf.write("\n")

AIS Specification Documents

• ITU-1371, ITU-1371-{1,2,3,4]
• e-Navigation
• IMO Circ 236
• IMO Circ 289
• EU RIS

Developing

The C++ code was switched to the Google style in November, 2012. Indenting should be by 2 spaces.

http://google-styleguide.googlecode.com/svn/trunk/cpplint/

$ git clone https://github.com/schwehr/libais
$ cd libais
$ virtualenv ve
$ source ve/bin/activate
$ pip install -e .[tests]
$ python setup.py test
$ py.test --cov=ais --cov-report term-missing

or

$ git clone https://github.com/schwehr/libais
$ cd libais
$ virtualenv ve
$ source ve/bin/activate
$ pip install -e .[test]
$ python setup.py develop
$ python setup.py test
$ py.test --cov=ais --cov-report term-missing