def METHOD_NAME(self):
    if self.data is None:
        self.path = None
        return
    if self.axisOrder == 'row-major':
        data = self.data.T
    else:
        data = self.data
    lines = fn.isocurve(data, self.level, connected=True, extendToEdge=True)
    self.path = QtGui.QPainterPath()
    for line in lines:
        self.path.moveTo(*line[0])
        for p in line[1:]:
            self.path.lineTo(*p)