class MeasureMapTool(QgsMapToolEmitPoint):
'''
MapTool for measuring distance and azimuth
Display result as tooltip on the canvas
'''
def __init__(self, canvas):
'''
Constructor
'''
self.canvas = canvas
super(MeasureMapTool, self).__init__(self.canvas)
self.canvas.destinationCrsChanged.connect(self.onCrsChange)
self.distArea = QgsDistanceArea()
self.distArea.setEllipsoid(u'WGS84')
self.onCrsChange()
self.rubberBand = QgsRubberBand(self.canvas)
self.rubberBand.setZValue(1e6)
self.rubberBand.setColor(Qt.red)
self.rubberBand.setWidth(1)
self.reset()
def reset(self):
self.startPoint = self.endPoint = None
self.rubberBand.reset()
def canvasPressEvent(self, e):
self.startPoint = self.toMapCoordinates(e.pos())
def canvasReleaseEvent(self, e):
self.startPoint = None
self.reset()
def canvasMoveEvent(self, e):
if not self.startPoint:
return
self.endPoint = self.toMapCoordinates(e.pos())
self.rubberBand.setToGeometry(
QgsGeometry.fromPolyline(
[QgsPoint(self.startPoint),
QgsPoint(self.endPoint)]), None)
if self.startPoint != self.endPoint:
dist = self.distArea.measureLine(self.startPoint, self.endPoint)
bearing = self.distArea.bearing(self.startPoint,
self.endPoint) * 180 / pi
if bearing < 0:
bearing += 360.0
text = u'{:.1f} m; {:.1f}\u00b0'.format(dist, bearing)
QToolTip.showText(self.canvas.mapToGlobal(e.pos()), text,
self.canvas)
def activate(self):
self.reset()
super(MeasureMapTool, self).activate()
def deactivate(self):
self.reset()
super(MeasureMapTool, self).deactivate()
@pyqtSlot()
def onCrsChange(self):
'''
SLot called when the mapcanvas CRS is changed
'''
crsDst = self.canvas.mapSettings().destinationCrs()
self.distArea.setSourceCrs(crsDst,
QgsProject.instance().transformContext())
