Subgroup: Scale
Class: QgsScaleCalculator¶
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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
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calculate
(self, mapExtent: QgsRectangle, canvasWidth: int) → 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.
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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
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mapUnits
(self) → QgsUnitTypes.DistanceUnit¶ Returns current map units
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setDpi
(self, dpi: float)¶ Sets the
dpi
(dots per inch) for the output resolution, to be used in scale calculations.See also
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setMapUnits
(self, mapUnits: QgsUnitTypes.DistanceUnit)¶ Set the map units
Parameters: mapUnits – Units of the data on the map. Must match a value from the