.. _docs-meteoinfolab-funcitons-plot-quiverkey:


*******************
quiverkey
*******************

.. currentmodule:: mipylib.plotlib.miplot

.. function:: quiverkey(*args, **kwargs)

    Add a key to a quiver plot.
    
    :param Q: (*MILayer*) The quiver layer instance returned by a call to quiver/quiverm.
    :param X: (*float*) The location x of the key.
    :param Y: (*float*) The location y of the key.
    :param label: (*string*) A string with the length and units of the key.
    :param coordinates=['axes'|'figure'|'data'|'inches']: (*string*) Coordinate system and units for 
        *X, Y*. 'axes' and 'figure' are normalized coordinate system with 0,0 in the lower left and 
        1,1 in the upper right, 'data' are the axes data coordinates (used for the locations of the 
        vectors in the quiver plot itself); 'inches' is position in the figure in inches, with 0,0 
        at the lower left corner.
    :param color: (*Color*) Overrides face and edge colors from Q.
    :param labelpos=['N'|'S'|'E'|'W']: (*string*) Position the label above, below, to the right, to
        the left of the arrow, respectively.
    :param labelsep: (*float*) Distance in inches between the arrow and the label. Default is 0.1.
    :param labelcolor: (*Color*) Label color. Default to default is black.
    :param fontproperties: (*dict*) A dictionary with keyword arguments accepted by the FontProperties
        initializer: *family, style, variant, size, weight*.
    
    **Example:**
    
    ::

        f = addfile('D:/Temp/GrADS/model.ctl')
        u = f['U'][0,'500','10:60','60:140']
        v = f['V'][0,'500','10:60','60:140']
        speed = sqrt(u*u+v*v)
        #Plot
        axesm()
        lworld = shaperead('D:/Temp/Map/country1.shp')
        geoshow(lworld)
        layer = quiverm(u, v, speed, 10, size=8)
        quiverkey(layer, 0.74, 0.18, 15, bbox={'edge':True, 'fill':True})
        colorbar(layer)
        title('Wind field')
        yticks([20,40,60])
        
    .. image:: ../../../../_static/vector.png