pro plotcirc, x, y, ap, color, _extra=extra

    th = findgen(361) * !pi/180.
    c = cos(th)
    s = sin(th)

    n = n_elements(x)

    if n_elements(ap) eq 1 then a = replicate(ap, n) else a = ap

    for i=0, n-1 do begin
        oplot, x[i]+c*a[i],y[i]+s*a[i], color=color, _extra=extra
    end
    
end