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help for circdplot
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Raw data plot for circular data with point symbols

        circdplot varname [if exp] [in range] [, clabel(label_specification)
                 ctick(numlist) fudge(#) resultant(resultant_options)
                 round(#) ticklength(#) unit(#) twoway_options ]


Description 

    circdplot produces a raw data plot for varname with point symbols showing
    values. varname should be a circular variable taking on values between 0
    and 360 degrees.

    Strictly, the values of varname are rounded to the nearest degree, or to
    the argument of round(). Rays of point symbols are drawn outwards from
    the circumference of a circle pointing in each direction present in the
    data.  The length of each ray is proportional to the frequency of that
    direction.  The resultant or mean direction is indicated by an arrow from
    the centre of the circle with length the radius of the circle X the
    vector strength. Hence an arrow representing a mean direction with vector
    strength 1 would touch the circle.

    The graph will usually best be shown with xsize() and ysize() equal, or
    nearly so. It may be helpful to know that the centre of the circle is at
    x = 0, y = 0 and that it has radius 1, so that the cardinal points North,
    East, South, West are at 0,1; 1,0; 0,-1; -1,0.


Options 

    clabel() specifies labels to be shown inside the circle at angles
        measured clockwise from 0 (North) through 360 degrees. Single text
        labels may be specified within " " following each label. For example,
        the default is clabel(0 "N" 90 "E" 180 "S" 270 "W").

    ctick() specifies positions of ticks to be shown inside the circle at
        angles measured clockwise from 0 (North) through 360 degrees.

    fudge() specifies a fudge factor controlling the radial spacing of point
        symbols. Default 1 means that the outermost point symbol will be
        plotted at distance from the circle equal to the radius of that
        circle. # means maximum distance # X that radius. Most graphs will
        need some hand-tuning of fudge() for better appearance. See also
        round().

    resultant() specifies options controlling the rendering of the arrow
        showing the resultant. In particular, arrowheadlength() specifies the
        arrowhead length (default 0.1).  Otherwise, such options are
        typically appropriate connect_options.

    round() indicates the bin or class width to be used (default 1 deg).  See
        also fudge().

    ticklength() specifies the tick length (default 0.05).

    unit() specifies that a point symbol should represent at most #
        observations, which number should be >= 1. That is, unit(10)
        specifies that a point symbol should represent at most 10
        observations.  Strictly, frequencies in each bin will be rounded up
        to the nearest multiple of #, so that with unit(10) 1 to 10
        observations would be represented by one point symbol, 11 to 20 two
        symbols, and so forth.

    twoway_options are options of twoway.  By default the subtitle()
        indicates the mean direction and vector strength and is at pos(6).
        Note that the degree symbol can be specified by `=char(176)'.


Example 

    . circdplot wallasp, result(clcolor(blue) clw(thick)) round(2)
        fudge(0.25) ms(Oh) mcolor(red) text(-0.5 0 "Wall aspect",
        size(large))
    . graph display, xsize(4) ysize(4)


Author

    Nicholas J. Cox, University of Durham, U.K.
    n.j.cox@durham.ac.uk


Also see

    On-line: help for circrplot (if installed), circvplot (if installed)