`nmea`¶

nmea - Imports GPS NMEA-formatted data files.

class upoints.nmea.Fix(time, latitude, longitude, quality, satellites, dilution, altitude, geoid_delta, dgps_delta=None, dgps_station=None, mode=None)[source]¶

Bases: upoints.point.Point

Class for representing a GPS NMEA-formatted system fix.

New in version 0.8.0.

Initialise a new Fix object.

Parameters:

time (datetime.time) – Time the fix was taken
latitude (float) – Fix’s latitude
longitude (float) – Fix’s longitude
quality (int) – Mode under which the fix was taken
satellites (int) – Number of tracked satellites
dilution (float) – Horizontal dilution at reported position
altitude (float) – Altitude above MSL
geoid_delta (float) – Height of geoid’s MSL above WGS84 ellipsoid
dgps_delta (float) – Number of seconds since last DGPS sync
dgps_station (int) – Identifier of the last synced DGPS station
mode (str) – Type of reading

static parse_elements(elements)[source]¶

Parse essential fix’s data elements.

Parameters:	elements (list) – Data values for fix
Returns:	Fix object representing data
Return type:	Fix

quality_string()[source]¶

Return a string version of the quality information.

Returns::: str: Quality information as string

class upoints.nmea.Locations(gpsdata_file=None)[source]¶

Bases: upoints.point.Points

Class for representing a group of GPS location objects.

New in version 0.8.0.

Initialise a new Locations object.

import_locations(gpsdata_file, checksum=True)[source]¶

Import GPS NMEA-formatted data files.

import_locations() returns a list of Fix objects representing the fix sentences found in the GPS data.

It expects data files in NMEA 0183 format, as specified in the official documentation, which is ASCII text such as:

$GPGSV,6,6,21,32,65,170,35*48
$GPGGA,142058,5308.6414,N,00300.9257,W,1,04,5.6,1374.6,M,34.5,M,,*6B
$GPRMC,142058,A,5308.6414,N,00300.9257,W,109394.7,202.9,191107,5,E,A*2C
$GPGSV,6,1,21,02,76,044,43,03,84,156,49,06,89,116,51,08,60,184,30*7C
$GPGSV,6,2,21,09,87,321,50,10,77,243,44,11,85,016,49,12,89,100,52*7A
$GPGSV,6,3,21,13,70,319,39,14,90,094,52,16,85,130,49,17,88,136,51*7E
$GPGSV,6,4,21,18,57,052,27,24,65,007,34,25,62,142,32,26,88,031,51*73
$GPGSV,6,5,21,27,64,343,33,28,45,231,16,30,84,198,49,31,90,015,52*7C
$GPGSV,6,6,21,32,65,170,34*49
$GPWPL,5200.9000,N,00013.2600,W,HOME*5E
$GPGGA,142100,5200.9000,N,00316.6600,W,1,04,5.6,1000.0,M,34.5,M,,*68
$GPRMC,142100,A,5200.9000,N,00316.6600,W,123142.7,188.1,191107,5,E,A*21

The reader only imports the GGA, or GPS fix, sentences currently but future versions will probably support tracks and waypoints. Other than that the data is out of scope for upoints.

The above file when processed by import_locations() will return the following list object:

[Fix(datetime.time(14, 20, 58), 53.1440233333, -3.01542833333, 1,
     4, 5.6, 1374.6, 34.5, None, None),
 Position(datetime.time(14, 20, 58), True, 53.1440233333,
          -3.01542833333, 109394.7, 202.9,
          datetime.date(2007, 11, 19), 5.0, 'A'),
 Waypoint(52.015, -0.221, 'Home'),
 Fix(datetime.time(14, 21), 52.015, -3.27766666667, 1, 4, 5.6,
     1000.0, 34.5, None, None),
 Position(datetime.time(14, 21), True, 52.015, -3.27766666667,
          123142.7, 188.1, datetime.date(2007, 11, 19), 5.0, 'A')]

Note

The standard is quite specific in that sentences must be less than 82 bytes, while it would be nice to add yet another validity check it isn’t all that uncommon for devices to break this requirement in their “extensions” to the standard.

Todo

Add optional check for message length, on by default

Parameters:	gpsdata_file (iter) – NMEA data to read checksum (bool) – Whether checksums should be tested
Returns:	Series of locations taken from the data
Return type:	list

class upoints.nmea.LoranPosition(latitude, longitude, time, status, mode=None)[source]¶

Bases: upoints.point.Point

Class for representing a GPS NMEA-formatted Loran-C position.

Initialise a new LoranPosition object.

Parameters:	latitude (float) – Fix’s latitude longitude (float) – Fix’s longitude time (datetime.time) – Time the fix was taken status (bool) – Whether the data is active mode (str) – Type of reading

mode_string()[source]¶

Return a string version of the reading mode information.

Returns:	Quality information as string
Return type:	str

static parse_elements(elements)[source]¶

Parse position data elements.

Parameters:	elements (list) – Data values for fix
Returns:	Fix object representing data
Return type:	Fix

upoints.nmea.MODE_INDICATOR = {'A': 'Autonomous', 'D': 'Differential', 'E': 'Estimated', 'M': 'Manual', 'N': 'Invalid', 'S': 'Simulated'}¶: NMEA’s mapping of code to reading type

class upoints.nmea.Position(time, status, latitude, longitude, speed, track, date, variation, mode=None)[source]¶

Bases: upoints.point.Point

Class for representing a GPS NMEA-formatted position.

New in version 0.8.0.

Initialise a new Position object.

Parameters:

time (datetime.time) – Time the fix was taken
status (bool) – Whether the data is active
latitude (float) – Fix’s latitude
longitude (float) – Fix’s longitude
speed (float) – Ground speed
track (float) – Track angle
date (datetime.date) – Date when position was taken
variation (float) – Magnetic variation
mode (str) – Type of reading

mode_string()[source]¶

Return a string version of the reading mode information.

Returns:	Quality information as string
Return type:	str

static parse_elements(elements)[source]¶

Parse position data elements.

Parameters:	elements (list) – Data values for position
Returns:	Position object representing data
Return type:	Position

class upoints.nmea.Waypoint(latitude, longitude, name)[source]¶

Bases: upoints.point.Point

Class for representing a NMEA-formatted waypoint.

New in version 0.8.0.

Initialise a new Waypoint object.

Parameters:	latitude (float) – Waypoint’s latitude longitude (float) – Waypoint’s longitude name (str) – Comment for waypoint

static parse_elements(elements)[source]¶

Parse waypoint data elements.

Parameters:	elements (list) – Data values for fix
Returns:	Object representing data
Return type:	nmea.Waypoint

upoints.nmea.calc_checksum(sentence)[source]¶

Calculate a NMEA 0183 checksum for the given sentence.

NMEA checksums are a simple XOR of all the characters in the sentence between the leading “$” symbol, and the “*” checksum separator.

Parameters:	sentence (str) – NMEA 0183 formatted sentence

upoints.nmea.nmea_latitude(latitude)[source]¶

Generate a NMEA-formatted latitude pair.

Parameters:	latitude (float) – Latitude to convert
Returns:	NMEA-formatted latitude values
Return type:	tuple

upoints.nmea.nmea_longitude(longitude)[source]¶

Generate a NMEA-formatted longitude pair.

Parameters:	longitude (float) – Longitude to convert
Returns:	NMEA-formatted longitude values
Return type:	tuple

upoints.nmea.parse_latitude(latitude, hemisphere)[source]¶

Parse a NMEA-formatted latitude pair.

Parameters:	latitude (str) – Latitude in DDMM.MMMM hemisphere (str) – North or South
Returns:	Decimal representation of latitude
Return type:	float

upoints.nmea.parse_longitude(longitude, hemisphere)[source]¶

Parse a NMEA-formatted longitude pair.

Parameters:	longitude (str) – Longitude in DDDMM.MMMM hemisphere (str) – East or West
Returns:	Decimal representation of longitude
Return type:	float

nmea¶

`nmea`¶