QNmeaPositionInfoSource#
The QNmeaPositionInfoSource
class provides positional information using a NMEA data source. More…
Synopsis#
Functions#
def
device
()def
parsePosInfoFromNmeaData
(data, posInfo, hasFix)def
setDevice
(source)def
setError
(positionError)def
setUserEquivalentRangeError
(uere)def
updateMode
()def
userEquivalentRangeError
()
Virtual functions#
def
parsePosInfoFromNmeaData
(data, size, posInfo, hasFix)
Note
This documentation may contain snippets that were automatically translated from C++ to Python. We always welcome contributions to the snippet translation. If you see an issue with the translation, you can also let us know by creating a ticket on https:/bugreports.qt.io/projects/PYSIDE
Detailed Description#
NMEA is a commonly used protocol for the specification of one’s global position at a certain point in time. The QNmeaPositionInfoSource
class reads NMEA data and uses it to provide positional data in the form of QGeoPositionInfo
objects.
A QNmeaPositionInfoSource
instance operates in either RealTimeMode
or SimulationMode
. These modes allow NMEA data to be read from either a live source of positional data, or replayed for simulation purposes from previously recorded NMEA data.
The source of NMEA data is set with setDevice()
.
Use startUpdates()
to start receiving regular position updates and stopUpdates()
to stop these updates. If you only require updates occasionally, you can call requestUpdate()
to request a single update.
In both cases the position information is received via the positionUpdated()
signal and the last known position can be accessed with lastKnownPosition()
.
QNmeaPositionInfoSource
supports reporting the accuracy of the horizontal and vertical position. To enable position accuracy reporting an estimate of the User Equivalent Range Error associated with the NMEA source must be set with setUserEquivalentRangeError()
.
- class PySide6.QtPositioning.QNmeaPositionInfoSource(updateMode[, parent=None])#
- Parameters:
updateMode –
UpdateMode
parent –
PySide6.QtCore.QObject
Constructs a QNmeaPositionInfoSource
instance with the given parent
and updateMode
.
- PySide6.QtPositioning.QNmeaPositionInfoSource.UpdateMode#
Defines the available update modes.
Constant
Description
QNmeaPositionInfoSource.RealTimeMode
Positional data is read and distributed from the data source as it becomes available. Use this mode if you are using a live source of positional data (for example, a GPS hardware device).
QNmeaPositionInfoSource.SimulationMode
The data and time information in the NMEA source data is used to provide positional updates at the rate at which the data was originally recorded. Use this mode if the data source contains previously recorded NMEA data and you want to replay the data for simulation purposes.
- PySide6.QtPositioning.QNmeaPositionInfoSource.device()#
- Return type:
Returns the NMEA data source.
See also
- PySide6.QtPositioning.QNmeaPositionInfoSource.parsePosInfoFromNmeaData(data, posInfo, hasFix)#
- Parameters:
data –
QByteArrayView
posInfo –
PySide6.QtPositioning.QGeoPositionInfo
hasFix – bool
- Return type:
bool
- PySide6.QtPositioning.QNmeaPositionInfoSource.parsePosInfoFromNmeaData(data, size, posInfo, hasFix)
- Parameters:
data – str
size – int
posInfo –
PySide6.QtPositioning.QGeoPositionInfo
hasFix – bool
- Return type:
bool
Parses an NMEA sentence string into a QGeoPositionInfo
.
The default implementation will parse standard NMEA sentences. This method should be reimplemented in a subclass whenever the need to deal with non-standard NMEA sentences arises.
The parser reads size
bytes from data
and uses that information to setup posInfo
and hasFix
. If hasFix
is set to false then posInfo
may contain only the time or the date and the time.
Returns true if the sentence was successfully parsed, otherwise returns false and should not modifiy posInfo
or hasFix
.
- PySide6.QtPositioning.QNmeaPositionInfoSource.setDevice(source)#
- Parameters:
source –
PySide6.QtCore.QIODevice
Sets the NMEA data source to device
. If the device is not open, it will be opened in QIODevice::ReadOnly mode.
The source device can only be set once and must be set before calling startUpdates()
or requestUpdate()
.
Note
The device
must emit QIODevice::readyRead() for the source to be notified when data is available for reading. QNmeaPositionInfoSource
does not assume the ownership of the device, and hence does not deallocate it upon destruction.
See also
- PySide6.QtPositioning.QNmeaPositionInfoSource.setError(positionError)#
- Parameters:
positionError –
Error
- PySide6.QtPositioning.QNmeaPositionInfoSource.setUserEquivalentRangeError(uere)#
- Parameters:
uere – float
Sets the User Equivalent Range Error (UERE) to uere
. The UERE is used in calculating an estimate of the accuracy of the position information reported by the position info source. The UERE should be set to a value appropriate for the GPS device which generated the NMEA stream.
The true UERE value is calculated from multiple error sources including errors introduced by the satellites and signal propogation delays through the atmosphere as well as errors introduced by the receiving GPS equipment. For details on GPS accuracy see Sam J. Wormley, GPS Errors & Estimating Your Reveiver’s Accuracy .
A typical value for UERE is approximately 5.1.
See also
- PySide6.QtPositioning.QNmeaPositionInfoSource.updateMode()#
- Return type:
Returns the update mode.
- PySide6.QtPositioning.QNmeaPositionInfoSource.userEquivalentRangeError()#
- Return type:
float
Returns the current User Equivalent Range Error (UERE). The UERE is used in calculating an estimate of the accuracy of the position information reported by the position info source. The default value is NaN which means no accuracy information will be provided.
See also