Class: QgsLinearReferencingSymbolLayer

Line symbol layer used for decorating according to linear referencing.

This symbol layer type allows placing text labels at regular intervals along a line (or at positions corresponding to existing vertices). Positions can be calculated using Cartesian distances, or interpolated from z or m values.

Added in version 3.40.

Class Hierarchy

Base classes

QgsLineSymbolLayer	Abstract base class for line symbol layers.
QgsSymbolLayer	Abstract base class for symbol layers.

Methods

averageAngleLength	Returns the length of line over which the line's direction is averaged when calculating individual label angles.
averageAngleMapUnitScale	Returns the map unit scale for the length over which the line's direction is averaged when calculating individual label angles.
averageAngleUnit	Returns the unit for the length over which the line's direction is averaged when calculating individual label angles.
interval	Returns the interval between labels.
labelOffset	Returns the offset between the line and linear referencing labels.
labelOffsetMapUnitScale	Returns the map unit scale used for calculating the offset between the line and linear referencing labels.
labelOffsetUnit	Returns the unit used for the offset between the line and linear referencing labels.
labelSource	Returns the label source, which dictates what quantity to use for the labels shown.
numericFormat	Returns the numeric format used to format the labels for the layer.
placement	Returns the placement mode for the labels.
rotateLabels	Returns True if the labels and symbols are to be rotated to match their line segment orientation.
setAverageAngleLength	Sets the length of line over which the line's direction is averaged when calculating individual label angles.
setAverageAngleMapUnitScale	Sets the map unit scale for the length over which the line's direction is averaged when calculating individual label angles.
setAverageAngleUnit	Sets the unit for the length over which the line's direction is averaged when calculating individual label angles.
setInterval	Sets the interval between labels.
setLabelOffset	Sets the offset between the line and linear referencing labels.
setLabelOffsetMapUnitScale	Sets the map unit scale used for calculating the offset between the line and linear referencing labels.
setLabelOffsetUnit	Sets the unit used for the offset between the line and linear referencing labels.
setLabelSource	Sets the label source, which dictates what quantity to use for the labels shown.
setNumericFormat	Sets the numeric format used to format the labels for the layer.
setPlacement	Sets the placement mode for the labels.
setRotateLabels	Sets whether the labels and symbols should be rotated to match their line segment orientation.
setShowMarker	Sets whether a marker symbol should be shown corresponding to the labeled point on line.
setSkipMultiplesOf	Sets the multiple distance to skip labels for.
setTextFormat	Sets the text format used to render the layer.
showMarker	Returns True if a marker symbol should be shown corresponding to the labeled point on line.
skipMultiplesOf	Returns the multiple distance to skip labels for.
textFormat	Returns the text format used to render the layer.

Static Methods

create

Creates a new QgsLinearReferencingSymbolLayer, using the specified properties.

class qgis.core.QgsLinearReferencingSymbolLayer

Bases: QgsLineSymbolLayer

averageAngleLength(self) → float

Returns the length of line over which the line’s direction is averaged when calculating individual label angles. Longer lengths smooth out angles from jagged lines to a greater extent.

Units are retrieved through averageAngleUnit()

See also

setAverageAngleLength()

See also

averageAngleUnit()

See also

averageAngleMapUnitScale()

Return type:

float

averageAngleMapUnitScale(self) → QgsMapUnitScale

Returns the map unit scale for the length over which the line’s direction is averaged when calculating individual label angles.

See also

setAverageAngleMapUnitScale()

See also

averageAngleLength()

See also

averageAngleUnit()

Return type:

QgsMapUnitScale

averageAngleUnit(self) → Qgis.RenderUnit

Returns the unit for the length over which the line’s direction is averaged when calculating individual label angles.

See also

setAverageAngleUnit()

See also

averageAngleLength()

See also

averageAngleMapUnitScale()

Return type:

Qgis.RenderUnit

static create(properties: Dict[str, Any] = {}) → QgsSymbolLayer | None

Creates a new QgsLinearReferencingSymbolLayer, using the specified properties.

The caller takes ownership of the returned object.

Parameters:

properties (Dict[str, Any] = {})

Return type:

Optional[QgsSymbolLayer]

interval(self) → float

Returns the interval between labels.

Units are always in the original layer CRS units.

See also

setInterval()

Return type:

float

labelOffset(self) → QPointF

Returns the offset between the line and linear referencing labels.

The unit for the offset is retrievable via labelOffsetUnit().

See also

setLabelOffset()

See also

labelOffsetUnit()

Return type:

QPointF

labelOffsetMapUnitScale(self) → QgsMapUnitScale

Returns the map unit scale used for calculating the offset between the line and linear referencing labels.

See also

setLabelOffsetMapUnitScale()

Return type:

QgsMapUnitScale

labelOffsetUnit(self) → Qgis.RenderUnit

Returns the unit used for the offset between the line and linear referencing labels.

See also

setLabelOffsetUnit()

See also

labelOffset()

Return type:

Qgis.RenderUnit

labelSource(self) → Qgis.LinearReferencingLabelSource

Returns the label source, which dictates what quantity to use for the labels shown.

See also

setLabelSource()

Return type:

Qgis.LinearReferencingLabelSource

numericFormat(self) → QgsNumericFormat | None

Returns the numeric format used to format the labels for the layer.

See also

setNumericFormat()

Return type:

Optional[QgsNumericFormat]

placement(self) → Qgis.LinearReferencingPlacement

Returns the placement mode for the labels.

See also

setPlacement()

Return type:

Qgis.LinearReferencingPlacement

rotateLabels(self) → bool

Returns True if the labels and symbols are to be rotated to match their line segment orientation.

See also

setRotateLabels()

Return type:

bool

setAverageAngleLength(self, length: float)

Sets the length of line over which the line’s direction is averaged when calculating individual label angles. Longer lengths smooth out angles from jagged lines to a greater extent.

Units are set through setAverageAngleUnit()

See also

averageAngleLength()

See also

setAverageAngleUnit()

See also

setAverageAngleMapUnitScale()

Parameters:

length (float)

setAverageAngleMapUnitScale(self, scale: QgsMapUnitScale)

Sets the map unit scale for the length over which the line’s direction is averaged when calculating individual label angles.

See also

averageAngleMapUnitScale()

See also

setAverageAngleLength()

See also

setAverageAngleUnit()

Parameters:

scale (QgsMapUnitScale)

setAverageAngleUnit(self, unit: Qgis.RenderUnit)

Sets the unit for the length over which the line’s direction is averaged when calculating individual label angles.

See also

averageAngleUnit()

See also

setAverageAngleLength()

See also

setAverageAngleMapUnitScale()

Parameters:

unit (Qgis.RenderUnit)

setInterval(self, interval: float)

Sets the interval between labels.

Units are always in the original layer CRS units.

See also

setInterval()

Parameters:

interval (float)

setLabelOffset(self, offset: QPointF | QPoint)

Sets the offset between the line and linear referencing labels.

The unit for the offset is set via setLabelOffsetUnit().

See also

labelOffset()

See also

setLabelOffsetUnit()

Parameters:

offset (Union[QPointF, QPoint])

setLabelOffsetMapUnitScale(self, scale: QgsMapUnitScale)

Sets the map unit scale used for calculating the offset between the line and linear referencing labels.

See also

labelOffsetMapUnitScale()

Parameters:

scale (QgsMapUnitScale)

setLabelOffsetUnit(self, unit: Qgis.RenderUnit)

Sets the unit used for the offset between the line and linear referencing labels.

See also

labelOffsetUnit()

See also

setLabelOffset()

Parameters:

unit (Qgis.RenderUnit)

setLabelSource(self, source: Qgis.LinearReferencingLabelSource)

Sets the label source, which dictates what quantity to use for the labels shown.

See also

labelSource()

Parameters:

source (Qgis.LinearReferencingLabelSource)

setNumericFormat(self, format: QgsNumericFormat | None)

Sets the numeric format used to format the labels for the layer.

Ownership of format is transferred to the layer.

See also

numericFormat()

Parameters:

format (Optional[QgsNumericFormat])

setPlacement(self, placement: Qgis.LinearReferencingPlacement)

Sets the placement mode for the labels.

See also

placement()

Parameters:

placement (Qgis.LinearReferencingPlacement)

setRotateLabels(self, rotate: bool)

Sets whether the labels and symbols should be rotated to match their line segment orientation.

See also

rotateLabels()

Parameters:

rotate (bool)

setShowMarker(self, show: bool)

Sets whether a marker symbol should be shown corresponding to the labeled point on line.

The marker symbol is set using setSubSymbol()

See also

showMarker()

Parameters:

show (bool)

setSkipMultiplesOf(self, multiple: float)

Sets the multiple distance to skip labels for.

If this value is non-zero, then any labels which are integer multiples of the returned value will be skipped. This allows creation of advanced referencing styles where a single QgsSymbol has multiple QgsLinearReferencingSymbolLayer symbol layers, eg allowing labeling every 100 in a normal font and every 1000 in a bold, larger font.

See also

skipMultiplesOf()

Parameters:

multiple (float)

setTextFormat(self, format: QgsTextFormat)

Sets the text format used to render the layer.

See also

textFormat()

Parameters:

format (QgsTextFormat)

showMarker(self) → bool

Returns True if a marker symbol should be shown corresponding to the labeled point on line.

The marker symbol is set using setSubSymbol()

See also

setShowMarker()

Return type:

bool

skipMultiplesOf(self) → float

Returns the multiple distance to skip labels for.

If this value is non-zero, then any labels which are integer multiples of the returned value will be skipped. This allows creation of advanced referencing styles where a single QgsSymbol has multiple QgsLinearReferencingSymbolLayer symbol layers, eg allowing labeling every 100 in a normal font and every 1000 in a bold, larger font.

See also

setSkipMultiplesOf()

Return type:

float

textFormat(self) → QgsTextFormat

Returns the text format used to render the layer.

See also

setTextFormat()

Return type:

QgsTextFormat