/// <summary>
        /// Writes the value expressed as a <c>spherical</c>, which is the direction specified as a spherical value <c>[Clock, Cone, Magnitude]</c>, with angles in radians and magnitude in meters.  The clock angle is measured in the XY plane from the positive X axis toward the positive Y axis.  The cone angle is the angle from the positive Z axis toward the negative Z axis.
        /// </summary>
        /// <param name="dates">The dates at which the value is specified.</param>
        /// <param name="values">The values corresponding to each date.</param>
        /// <param name="startIndex">The index of the first element to write.</param>
        /// <param name="length">The number of elements to write.</param>
        public void WriteSpherical(IList <JulianDate> dates, IList <Spherical> values, int startIndex, int length)
        {
            const string PropertyName = SphericalPropertyName;

            OpenIntervalIfNecessary();
            CesiumWritingHelper.WriteSpherical(Output, PropertyName, dates, values, startIndex, length);
        }
        /// <summary>
        /// Writes the value expressed as a <c>spherical</c>, which is the direction specified as a spherical value <c>[Clock, Cone, Magnitude]</c>, with angles in radians and magnitude in meters.  The clock angle is measured in the XY plane from the positive X axis toward the positive Y axis.  The cone angle is the angle from the positive Z axis toward the negative Z axis.
        /// </summary>
        /// <param name="value">The value.</param>
        public void WriteSpherical(Spherical value)
        {
            const string PropertyName = SphericalPropertyName;

            OpenIntervalIfNecessary();
            Output.WritePropertyName(PropertyName);
            CesiumWritingHelper.WriteSpherical(Output, value);
        }