Class: QgsScaleCalculator

class qgis.core.QgsScaleCalculator(dpi: float = 0, mapUnits: QgsUnitTypes.DistanceUnit = QgsUnitTypes.DistanceMeters)

Bases: sip.wrapper

Constructor

Parameters:
  • dpi – Monitor resolution in dots per inch
  • mapUnits – Units of the data on the map

QgsScaleCalculator(QgsScaleCalculator)

Calculates scale for a given combination of canvas size, map extent, and monitor dpi.

Methods

calculate Calculate the scale denominator
calculateGeographicDistance Calculate the distance between two points in geographic coordinates.
dpi Returns the DPI (dots per inch) used in scale calculations.
mapUnits Returns current map units
setDpi Sets the dpi (dots per inch) for the output resolution, to be used in scale calculations.
setMapUnits Set the map units

Signals

Attributes

calculate(self, mapExtent: QgsRectangle, canvasWidth: float) → float

Calculate the scale denominator

Parameters:
  • mapExtent – QgsRectangle containing the current map extent
  • canvasWidth – Width of the map canvas in pixel (physical) units
Returns:

scale denominator of current map view, e.g. 1000.0 for a 1:1000 map.

calculateGeographicDistance(self, mapExtent: QgsRectangle) → float

Calculate the distance between two points in geographic coordinates. Used to calculate scale for map views with geographic (decimal degree) data.

Parameters:mapExtent – QgsRectangle containing the current map extent
dpi(self) → float

Returns the DPI (dots per inch) used in scale calculations.

See also

setDpi()

mapUnits(self) → QgsUnitTypes.DistanceUnit

Returns current map units

setDpi(self, dpi: float)

Sets the dpi (dots per inch) for the output resolution, to be used in scale calculations.

See also

dpi()

setMapUnits(self, mapUnits: QgsUnitTypes.DistanceUnit)

Set the map units

Parameters:mapUnits – Units of the data on the map. Must match a value from the