https://github.com/Knio/pynmea2

Python library for parsing the NMEA 0183 protocol (GPS)
https://github.com/Knio/pynmea2

gps gps-data nmea-parser nmea-protocol nmea-sentences nmea0183 pynmea2 python

Last synced: 26 days ago
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Python library for parsing the NMEA 0183 protocol (GPS)

• Host: GitHub
• URL: https://github.com/Knio/pynmea2
• Owner: Knio
• License: mit
• Created: 2013-07-04T04:49:36.000Z (over 11 years ago)
• Default Branch: master
• Last Pushed: 2024-04-28T15:02:43.000Z (8 months ago)
• Last Synced: 2024-11-20T18:26:45.716Z (about 1 month ago)
• Topics: gps, gps-data, nmea-parser, nmea-protocol, nmea-sentences, nmea0183, pynmea2, python
• Language: Python
• Homepage:
• Size: 268 KB
• Stars: 634
• Watchers: 50
• Forks: 223
• Open Issues: 35
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
# pynmea2

`pynmea2` is a python library for the [NMEA 0183](http://en.wikipedia.org/wiki/NMEA_0183) protocol

`pynmea2` is based on [`pynmea`](https://code.google.com/p/pynmea/) by Becky Lewis

The `pynmea2` homepage is located at 

## Compatibility

`pynmea2` is compatable with Python 2.7 and Python 3.4+

![Python version](https://img.shields.io/pypi/pyversions/pynmea2.svg?style=flat)

[![Build status](https://github.com/Knio/pynmea2/actions/workflows/ci.yml/badge.svg?branch=master)](https://github.com/Knio/pynmea2/actions/workflows/ci.yml?query=branch%3Amaster+)

[![Coverage status](https://img.shields.io/coveralls/github/Knio/pynmea2/master.svg?style=flat)](https://coveralls.io/r/Knio/pynmea2?branch=master)

## Installation

The recommended way to install `pynmea2` is with

[pip](http://pypi.python.org/pypi/pip/):

```bash

pip install pynmea2

```

[![PyPI version](https://img.shields.io/pypi/v/pynmea2.svg?style=flat)](https://pypi.org/project/pynmea2/)

[![PyPI downloads](https://img.shields.io/pypi/dm/pynmea2.svg?style=flat)](https://pypi.org/project/pynmea2/)

## Parsing

You can parse individual NMEA sentences using the `parse(data, check=False)` function, which takes a string containing a

NMEA 0183 sentence and returns a `NMEASentence` object. Note that the leading '$' is optional and trailing whitespace is ignored when parsing a sentence.

With `check=False`, `parse` will accept NMEA messages that do not have checksums, however it will still raise `pynmea2.ChecksumError` if they are present. `check=True` will also raise `ChecksumError` if the checksum is missing.

Example:

```python

>>> import pynmea2

>>> msg = pynmea2.parse("$GPGGA,184353.07,1929.045,S,02410.506,E,1,04,2.6,100.00,M,-33.9,M,,0000*6D")

>>> msg

```

The `NMEASentence` object has different properties, depending on its sentence type.

The `GGA` message has the following properties:

```python

>>> msg.timestamp

datetime.time(18, 43, 53)

>>> msg.lat

'1929.045'

>>> msg.lat_dir

'S'

>>> msg.lon

'02410.506'

>>> msg.lon_dir

'E'

>>> msg.gps_qual

'1'

>>> msg.num_sats

'04'

>>> msg.horizontal_dil

'2.6'

>>> msg.altitude

100.0

>>> msg.altitude_units

'M'

>>> msg.geo_sep

'-33.9'

>>> msg.geo_sep_units

'M'

>>> msg.age_gps_data

''

>>> msg.ref_station_id

'0000'

```

Additional properties besides the ones explicitly in the message data may also exist.

For example, `latitude` and `longitude` properties exist as helpers to access the geographic coordinates as python floats ([DD](http://en.wikipedia.org/wiki/Decimal_degrees), "decimal degrees") instead of the DDDMM.MMMM ("Degrees, minutes, seconds") format used in the NMEA protocol. `latitude_minutes`, `latitude_seconds`, `longitude_minutes`, and `longitude_seconds` are also supported and allow easy creation of differently formatted location strings.

```python

>>> msg.latitude

-19.4840833333

>>> msg.longitude

24.1751

>>> '%02d°%07.4f′' % (msg.latitude, msg.latitude_minutes)

'-19°29.0450′'

>>> '%02d°%02d′%07.4f″' % (msg.latitude, msg.latitude_minutes, msg.latitude_seconds)

"-19°29′02.7000″"

```

## Generating

You can create a `NMEASentence` object by calling the constructor with talker, message type, and data fields:

```python

>>> import pynmea2

>>> msg = pynmea2.GGA('GP', 'GGA', ('184353.07', '1929.045', 'S', '02410.506', 'E', '1', '04', '2.6', '100.00', 'M', '-33.9', 'M', '', '0000'))

```

and generate a NMEA string from a `NMEASentence` object:

```python

>>> str(msg)

'$GPGGA,184353.07,1929.045,S,02410.506,E,1,04,2.6,100.00,M,-33.9,M,,0000*6D'

```

## File reading example

See [examples/read_file.py](/examples/read_file.py)

```python

import pynmea2

file = open('examples/data.log', encoding='utf-8')

for line in file.readlines():

    try:

        msg = pynmea2.parse(line)

        print(repr(msg))

    except pynmea2.ParseError as e:

        print('Parse error: {}'.format(e))

        continue

```

## `pySerial` device example

See [examples/read_serial.py](/examples/read_serial.py)

```python

import io

import pynmea2

import serial

ser = serial.Serial('/dev/ttyS1', 9600, timeout=5.0)

sio = io.TextIOWrapper(io.BufferedRWPair(ser, ser))

while 1:

    try:

        line = sio.readline()

        msg = pynmea2.parse(line)

        print(repr(msg))

    except serial.SerialException as e:

        print('Device error: {}'.format(e))

        break

    except pynmea2.ParseError as e:

        print('Parse error: {}'.format(e))

        continue

```