pyrate package

Subpackages

• pyrate.algorithms package
  • Submodules
  • pyrate.algorithms.aisparser module
  • pyrate.algorithms.imolist module
  • pyrate.algorithms.vesselimporter module
  • Module contents
• pyrate.repositories package
  • Submodules
  • pyrate.repositories.aisdb module
  • pyrate.repositories.file module
  • pyrate.repositories.sql module
    • PgsqlRepository
    • Table
  • Module contents
• pyrate.tools package
  • Submodules
  • pyrate.tools.resampler module
  • Module contents

Submodules

pyrate.cli module

Provides a command line interface to the pyrate library

The command line interface (CLI) expects that a configuration file named ‘aistool.conf’ is located in the current folder.

If the config file is not present, a runtime error is raised, and the commands set_default can be used to generate a default configuration file.

pyrate.cli.main()

The command line interface

Type pyrate –help for help on how to use the command line interface

pyrate.config_setter module

Generates a default config file in current folder

pyrate.config_setter.gen_default_config(*args)

Generates a default config file in current folder

This command generates a default configuration file and folder structure in the current folder.

The folders generated are:

repositories

To hold additional repository code for pyrate

algorithms

To hold additional algorithm code for pyrate

aiscsv

For AIS csv files (required by algorithms/aisparser.py)

baddata

For AIS import logfiles (required by algorithms/aisparser.py)

pyrate.loader module

This module provides the Loader class which loads a pyrate session from a configuation file. This session can then run tasks on data repositories and algorithms.

class pyrate.loader.Loader(config=None)

Bases: object

The Loader joins together data repositories and algorithms, and executes operations on them.

execute_algorithm_command(algname, command, **args)

Execute the specified command on the specified algorithm

execute_repository_command(reponame, command, **args)

Execute the specified command on the specified repository.

get_algorithm(name)

Returns the algorithm module specified.

get_algorithm_commands(algname)

Returns a list of available commands for the specified algorithm

get_algorithms()

Returns a set of the names of available algorithms

get_data_repositories()

Returns a set of the names of available data repositories

get_data_repository(name, readonly=False)

Returns a loaded instance of the specified data repository.

get_repository_commands(repo_name)

Returns a list of available commands for the specified repository

pyrate.loader.load_all_modules(paths)

Load all modules on the given paths.

pyrate.loader.load_module(name, paths)

Load module name using the given search paths.

pyrate.utils module

pyrate.utils.detect_location_outliers(msg_stream, as_df=False)

Detects outlier messages by submitting messages to a speed test

The algorithm proceeds as follows:

1. Create a linked list of all messages with non-null locations (pointing to next message)

2. Loop through linked list and check for location outliers:

   • A location outlier is who does not pass the speed test (<= 50kn; link is ‘discarded’ when not reached in time)

   • No speed test is performed when:

     • distance too small (< 0.054nm ~ 100m; catches most positioning inaccuracies) => no outlier
     • time gap too big (>= 215h ~ 9d; time it takes to get anywhere on the globe at 50kn not respecting land) => next message is new ‘start’

   If an alledged outlier is found its link is set to be the current message’s link

3. The start of a linked list becomes special attention: if speed check fails, the subsequent link is tested

Line of thinking is: Can I get to the next message in time? If not ‘next’ must be an outlier, go to next but one.

Parameters:

• msg_stream – A list of dictionaries representing AIS messages for a single MMSI number. Dictionary keys correspond to the column names from the ais_clean table. The list of messages should be ordered by timestamp in ascending order.
• as_df (bool, optional) – Set to True if msg_stream are passed as a pandas DataFrame

Returns:

The rows in the message stream which are outliers

Return type:

outlier_rows

pyrate.utils.interpolate_passages(msg_stream)

Interpolate far apart points in an ordered stream of messages.

Parameters:msg_stream – A list of dictionaries representing AIS messages for a single MMSI number. Dictionary keys correspond to the column names from the ais_clean table. The list of messages should be ordered by timestamp in ascending order. Returns:artificial_messages – A list of artificial messages to fill in gaps/navigate around land. Return type:list

pyrate.utils.is_valid_cog(cog)

Validates course over ground

Parameters:cog (float) – Course over ground Returns: Return type:True if course over ground is greater than zero and less than 360 degrees

pyrate.utils.is_valid_heading(heading)

Validates heading

Parameters:heading (float) – The heading of the ship in degrees Returns: Return type:True if heading is greater than zero and less than 360 degrees

pyrate.utils.is_valid_sog(sog)

Validates speed over ground

Parameters:sog (float) – Speed over ground Returns: Return type:True if speed over ground is greater than zero and less than 102.2

pyrate.utils.speed_calc(msg_stream, index1, index2)

Computes the speed between two messages in the message stream

Parameters:

• msg_stream – A list of dictionaries representing AIS messages for a single MMSI number. Dictionary keys correspond to the column names from the ais_clean table. The list of messages should be ordered by timestamp in ascending order.
• index1 (int) – The index of the first message
• index2 (int) – The index of the second message

Returns:

• timediff (datetime) – The difference in time between the two messages in datetime
• dist (float) – The distance between messages in nautical miles
• speed (float) – The speed in knots

pyrate.utils.valid_imo(imo=0)

Check valid IMO using checksum.

Parameters:imo (integer) – An IMO ship identifier Returns: Return type:True if the IMO number is valid

Notes

Taken from Eoin O’Keeffe’s checksum_valid function in pyAIS

pyrate.utils.valid_latitude(lat)

Check valid latitude.

Parameters:lon (integer) – A latitude Returns: Return type:True if the latitude is valid

pyrate.utils.valid_longitude(lon)

Check valid longitude.

Parameters:lon (integer) – A longitude Returns: Return type:True if the longitude is valid

pyrate.utils.valid_message_id(message_id)

pyrate.utils.valid_mmsi(mmsi)

Checks if a given MMSI number is valid.

Parameters:mmsi (int) – An MMSI number Returns: Return type:Returns True if the MMSI number is 9 digits long.

pyrate.utils.valid_navigational_status(status)

Module contents

pyrate.get_resource_filename(resource_name)

Returns the absolute path associated with the file

Parameters:path (str) – The expected file path Returns:path – The absolute file path Return type:str