0.7.3

What's Changed

• Support input from serial sources on Windows by @astuder in #4
• fix lon/lat in msg type 27, possibly now also works in types 17 and 22 by @astuder in #5
• Adding support for checksum status in stats

New Contributors

• @astuder made their first contribution in #4

Full Changelog: v0.7.1...v0.7.3

Lossy compression added

AIS is meant for maintaining a real-time display, so that you don't hit other ships. That means for other uses, there's a lot of pretty-much-redundant information. This library now includes the aisrefine tool, which will take a large file and perform lossy compression. At a minimum you'll see one AIS sentence every four hours from a sender, and more if the ship significantly changes things like speed, destination, course, or draught. This provides circa 96% compression on large files, and was a much easier way to speed up the library than rewriting everything in C.

Release available on PYPI: https://pypi.org/project/simpleais/

Can now export AIS to JSON

To make it easier to interoperate with other languages, there is now the ais2json commmand-line tool and support in the Sentence object for converting sentences to JSON. Field order is preserved to make the JSON human-readable. So that no information is accidentally lost, the original encoded AIS text is attached.

The JSON format is much more verbose, but that can be compensated for via compression. A quick test on a 2 GB raw AIS file shows that raw AIS is about 79 bytes per sentence, while a gzipped JSON version is about 64 bytes per sentence.

Sentences can be converted to dicts

So that sentences can be easily encoded as, e.g., JSON, they can now be converted to dicts.

Now with time filtering

This lets you filter AIS packets by timestamp; aisgrep now has --before and --after options. Date format can be anything accepted by the dateutil package, which is almost anything.

Better, faster, stronger

Contains a variety of improvements, including transparent reading of .gz files, defaulting to quietly ignoring bad lines, and significant speed improvements.

v0.6.1

Making sure the magic JSON file gets deployed.

Initial release

A release of some basic library and tool code. Since I'm using this in production, perhaps others will want to as well.