`twisted.positioning.base.PositionError(FancyEqMixin, object)`

class documentation`twisted.positioning.base`

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Position error information.

Instance Variable | pdop | The position dilution of precision. `None` if unknown. (type: `float` or `NoneType` ) |

Instance Variable | hdop | The horizontal dilution of precision. `None` if unknown. (type: `float` or `NoneType` ) |

Instance Variable | vdop | The vertical dilution of precision. `None` if unknown. (type: `float` or `NoneType` ) |

Method | __init__ | Initializes a positioning error object. |

Method | __repr__ | Returns a string representation of positioning information object. |

Class Variable | _ALLOWABLE_THRESHOLD | The maximum allowable difference between PDOP and the geometric mean of
VDOP and HDOP. That difference is supposed to be zero, but can be non-zero
because of rounding error and limited reporting precision. You should never
have to change this value. (type: `float` ) |

Class Variable | _DOP_EXPRESSIONS | A mapping of DOP types (C[hvp]dop) to a list of callables that take self
and return that DOP type, or raise `TypeError` . This allows a
DOP value to either be returned directly if it's know, or computed from
other DOP types if it isn't. (type: `dict` of `str` to callables) |

Method | _testDilutionOfPositionInvariant | Tests if this positioning error object satisfies the dilution of
position invariant (PDOP = (HDOP**2 + VDOP**2)*.5), unless the
`self._testInvariant` instance variable is
`False` . |

Method | _getDOP | Gets a particular dilution of position value. |

Method | _setDOP | Sets a particular dilution of position value. |

Inherited from FancyEqMixin:

Method | __eq__ | Undocumented |

Method | __ne__ | Undocumented |

_ALLOWABLE_THRESHOLD =

The maximum allowable difference between PDOP and the geometric mean of
VDOP and HDOP. That difference is supposed to be zero, but can be non-zero
because of rounding error and limited reporting precision. You should never
have to change this value. (type:

`float`

)
_DOP_EXPRESSIONS =

A mapping of DOP types (C[hvp]dop) to a list of callables that take self
and return that DOP type, or raise

`TypeError`

. This allows a
DOP value to either be returned directly if it's know, or computed from
other DOP types if it isn't. (type: `dict`

of `str`

to callables)
def
__init__(self, pdop=None, hdop=None, vdop=None, testInvariant=False):
(source)

Initializes a positioning error object.

Parameters | pdop | The position dilution of precision. `None` if unknown. (type: `float` or `NoneType` ) |

hdop | The horizontal dilution of precision. `None` if unknown. (type: `float` or `NoneType` ) | |

vdop | The vertical dilution of precision. `None` if unknown. (type: `float` or `NoneType` ) | |

testInvariant | Flag to test if the DOP invariant is valid or not. If `True` ,
the invariant (PDOP = (HDOP**2 + VDOP**2)*.5) is checked at every mutation.
By default, this is false, because the vast majority of DOP-providing
devices ignore this invariant. (type: c{bool}) |

def
_testDilutionOfPositionInvariant(self):
(source)

Tests if this positioning error object satisfies the dilution of
position invariant (PDOP = (HDOP**2 + VDOP**2)*.5), unless the
`self._testInvariant`

instance variable is
`False`

.

Returns | `None` if the invariant was not satisfied or not tested. | |

Raises | ValueError | Raised if the invariant was tested but not satisfied. |

def
_getDOP(self, dopType):
(source)

Gets a particular dilution of position value.

Parameters | dopType | The type of dilution of position to get. One of ('pdop', 'hdop', 'vdop'). (type: `str` ) |

Returns | The DOP if it is known, `None` otherwise. (type: `float` or `NoneType` ) |

def
_setDOP(self, dopType, value):
(source)

Sets a particular dilution of position value.

Parameters | dopType | The type of dilution of position to set. One of ('pdop', 'hdop', 'vdop'). (type: `str` ) |

value | The value to set the dilution of position type to. (type: `float`
If this position error tests dilution of precision invariants, it will
be checked. If the invariant is not satisfied, the assignment will be
undone and |

def
__repr__(self):
(source)

Returns a string representation of positioning information object.

Returns | The string representation. (type: `str` ) |