public double Sum(double y) { Accumulator a = new Accumulator(this); a.Add(y); return(a._s); }
/** * Add a point to the polygon or polyline. * <p> * @param lat the latitude of the point (degrees). * @param lon the latitude of the point (degrees). * <p> * <i>lat</i> should be in the range [−90°, 90°]. **********************************************************************/ public void AddPoint(double lat, double lon) { lon = GeoMath.AngNormalize(lon); if (_num == 0) { _lat0 = _lat1 = lat; _lon0 = _lon1 = lon; } else { GeodesicData g = _earth.Inverse(_lat1, _lon1, lat, lon, _mask); _perimetersum.Add(g.Distance); if (!_polyline) { _areasum.Add(g.GeodesicScale12); _crossings += Transit(_lon1, lon); } _lat1 = lat; _lon1 = lon; } ++_num; }
/** * Return the results so far. * <p> * @param reverse if true then clockwise (instead of counter-clockwise) * traversal counts as a positive area. * @param sign if true then return a signed result for the area if * the polygon is traversed in the "wrong" direction instead of returning * the area for the rest of the earth. * @return PolygonResult(<i>num</i>, <i>perimeter</i>, <i>area</i>) where * <i>num</i> is the number of vertices, <i>perimeter</i> is the perimeter * of the polygon or the length of the polyline (meters), and <i>area</i> * is the area of the polygon (meters<sup>2</sup>) or Double.NaN of * <i>polyline</i> is true in the constructor. * <p> * More points can be added to the polygon after this call. **********************************************************************/ public PolygonResult Compute(bool reverse, bool sign) { if (_num < 2) { return(new PolygonResult(_num, 0, _polyline ? Double.NaN : 0)); } if (_polyline) { return(new PolygonResult(_num, _perimetersum.Sum(), Double.NaN)); } GeodesicData g = _earth.Inverse(_lat1, _lon1, _lat0, _lon0, _mask); Accumulator tempsum = new Accumulator(_areasum); tempsum.Add(g.GeodesicScale12); int crossings = _crossings + Transit(_lon1, _lon0); if ((crossings & 1) != 0) { tempsum.Add((tempsum.Sum() < 0 ? 1 : -1) * _area0 / 2); } // area is with the clockwise sense. If !reverse convert to // counter-clockwise convention. if (!reverse) { tempsum.Negate(); } // If sign put area in (-area0/2, area0/2], else put area in [0, area0) if (sign) { if (tempsum.Sum() > _area0 / 2) { tempsum.Add(-_area0); } else if (tempsum.Sum() <= -_area0 / 2) { tempsum.Add(+_area0); } } else { if (tempsum.Sum() >= _area0) { tempsum.Add(-_area0); } else if (tempsum.Sum() < 0) { tempsum.Add(+_area0); } } return (new PolygonResult(_num, _perimetersum.Sum(g.Distance), 0 + tempsum.Sum())); }