How to get co ordinates of points on mouse click in PyQGIS

I want to get x/y co-ordinates of point on mouse click for a point and need to use those co-ordinates to evaluate other value as per others module already define .

How can I get x y coordinates on mouse click in QGIS and print those in PyQGIS.

Answer

You need QgsMapToolEmitPoint class to do that. Following code works well for that purpose:

from qgis.gui import QgsMapToolEmitPoint

def display_point( pointTool ): 

    print '({:.4f}, {:.4f})'.format(pointTool[0], pointTool[1])

# a reference to our map canvas 
canvas = iface.mapCanvas() 


# this QGIS tool emits as QgsPoint after each click on the map canvas
pointTool = QgsMapToolEmitPoint(canvas)

pointTool.canvasClicked.connect( display_point )

canvas.setMapTool( pointTool )

However, if you prefer a class, following code can also be used:

from qgis.gui import QgsMapToolEmitPoint


class PrintClickedPoint(QgsMapToolEmitPoint):
    def __init__(self, canvas):
        self.canvas = canvas
        QgsMapToolEmitPoint.__init__(self, self.canvas)

    def canvasPressEvent( self, e ):
        point = self.toMapCoordinates(self.canvas.mouseLastXY())
        print '({:.4f}, {:.4f})'.format(point[0], point[1])


canvas_clicked = PrintClickedPoint( iface.mapCanvas() )
iface.mapCanvas().setMapTool( canvas_clicked )