Ejemplo n.º 1
0
        internal int SouthEast(HealCoor basin)
        {
            int newRing, newPixelInRing;

            North(basin.Symmetric(_healpixManager), NeighborHor.West, out newRing, out newPixelInRing);
            _healpixManager.Symmetric(ref newRing, ref newPixelInRing);
            return(_healpixManager.GetP(newRing, newPixelInRing));
        }
Ejemplo n.º 2
0
        /// <returns>P, index in all HEALPix grid</returns>
        public int NorthMean(HealCoor basin)
        {
            // last basin in north ring
            var northP            = basin.P - basin.PixelInRing;
            var pixelsInNorthRing = _healpixManager.PixelsCountInRing(basin.Ring - 1);
            var northPixelInRing  = basin.PixelInRing * pixelsInNorthRing /
                                    basin.PixelsCountInRing /* _healpixManager.PixelsCountInRing(basin.Ring) */;

            return(northP - pixelsInNorthRing + Math.Max(1, northPixelInRing));
        }
Ejemplo n.º 3
0
        public int Get(Direction direction, HealCoor basin)
        {
            switch (direction)
            {
            case Direction.Ne:
                return(NorthEast(basin));

            case Direction.Nw:
                return(NorthWest(basin));

            case Direction.Se:
                return(SouthEast(basin));

            default:
            case Direction.Sw:
                return(SouthWest(basin));
            }
        }
Ejemplo n.º 4
0
        /// <returns>angle</returns>
        public double DistanceTo(HealCoor coor)
        {
            var φ1 = Phi;
            var φ2 = coor.Phi;
            var Δφ = Phi - coor.Phi;
            var Δλ = Lambda.Value - coor.Lambda.Value;
            //* haversine formula1
            var a = Math.Sin(Δφ / 2) * Math.Sin(Δφ / 2) +
                    Math.Cos(φ1) * Math.Cos(φ2) *
                    Math.Sin(Δλ / 2) * Math.Sin(Δλ / 2);
            var c = 2 * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1 - a));

            return(c);

            /*  Spherical Law of Cosines
             *
             * var d = Math.Acos(Math.Sin(φ1) * Math.Sin(φ2) + Math.Cos(φ1) * Math.Cos(φ2) * Math.Cos(Δλ));
             *
             * return d; */
        }
Ejemplo n.º 5
0
        /// <summary>
        /// maybe better reuse code from 5.3 Pixel Boundaries
        /// https://www.researchgate.net/publication/1801816_HEALPix_A_Framework_for_High-Resolution_Discretization_and_Fast_Analysis_of_Data_Distributed_on_the_Sphere
        /// </summary>
        public Ray3D MeanBoundary(HealCoor basin, Direction to)
        {
            var deltaX            = 360d / (basin.PixelsCountInRing * 2);
            var deltaXsign        = GetHor(to) == (int)NeighborHor.East ? 1 : -1;
            var sameRingBoundaryX = basin.X + deltaXsign * deltaX;

            var    toBasin  = _healpixManager.GetCenter <HealCoor>(Get(to, basin));
            var    toBasinX = toBasin.X;
            double?toBasinY;

            if (basin.Ring == 1 && GetVert(to) == NeighborVert.North)
            {
                toBasinY = 90;
            }
            else if (basin.Ring == _healpixManager.RingsCount && GetVert(to) == NeighborVert.South)
            {
                toBasinY = -90;
            }
            else
            {
                var boundaryRing   = basin.Ring + (GetVert(to) == NeighborVert.North ? -1 : 1);
                var boundaryDeltaX = 360d / (_healpixManager.PixelsCountInRing(boundaryRing) * 2);
                if (toBasin.Ring == basin.Ring)
                {
                    var toBasinOppositeHor = _healpixManager.GetCenter <HealCoor>(Get(GetOppositeHor(to), basin));
                    toBasinY = toBasinOppositeHor.Y;
                    toBasinX = toBasinOppositeHor.X + deltaXsign * boundaryDeltaX;
                }
                else
                {
                    toBasinY = toBasin.Y;
                    toBasinX = toBasinX - deltaXsign * boundaryDeltaX;
                }
            }

            var bisector = Matrixes.Rotate(new HealCoor(toBasinX, toBasinY.Value))
                           + Matrixes.Rotate(new HealCoor(sameRingBoundaryX, basin.Y));

            return(new Ray3D(Basin3.O3, bisector));
        }
Ejemplo n.º 6
0
 internal int NorthEast(HealCoor basin)
 {
     return(North(basin, NeighborHor.East));
 }
Ejemplo n.º 7
0
        private int North(HealCoor basin, NeighborHor hor, out int newRing, out int newPixelInRing)
        {
            newRing = basin.Ring - 1;
            var ringFirstP = basin.P - basin.PixelInRing + 1;
            var eastIndex  = hor == NeighborHor.East ? 1 : 0;
            int newP;

            switch (basin.NorthCap)
            {
            case true:
                if ((basin.PixelInRing - eastIndex) % basin.Ring == 0)
                {
                    newRing++;
                    newP = hor == NeighborHor.East ? basin.EastInRing : basin.WestInRing;
                }
                else
                {
                    newP        = basin.P;
                    ringFirstP -= basin.PixelsCountInRing - 4;
                    newP       -= basin.PixelsCountInRing - 4
                                  + eastIndex + (basin.PixelInRing - 1) / basin.Ring;
                }
                break;

            case false:
                newP = basin.P;
                // border between equator and south cap
                if (basin.Ring == 3 * _healpixManager.Nside)
                {
                    ringFirstP -= basin.PixelsCountInRing;
                    newP       -= basin.PixelInRing == eastIndex ? 1 : basin.PixelsCountInRing + eastIndex;
                }
                else
                {
                    var ringFromPole = _healpixManager.RingsCount - basin.Ring + 1;

                    ringFirstP -= basin.PixelsCountInRing + 4;
                    newP       -= basin.PixelsCountInRing + 4
                                  + (eastIndex == 1 ? 0 : -1) - (basin.PixelInRing - 1) / ringFromPole;
                }
                break;

            default:
                ringFirstP -= basin.PixelsCountInRing;

                // exact equator
                if (basin.Ring % 2 == 0 && _healpixManager.K > 0)
                {
                    newP = hor == NeighborHor.East ? basin.EastInRing : basin.P;
                }
                else
                {
                    newP = hor == NeighborHor.East ? basin.P : basin.WestInRing;
                }

                newP -= basin.PixelsCountInRing;     // PixelsCountInRing on equator and first polar cap the same
                break;
            }

            newPixelInRing = newP - ringFirstP + 1;
            return(newP);
        }
Ejemplo n.º 8
0
        /// <returns>P, from 0</returns>
        private int North(HealCoor basin, NeighborHor hor)
        {
            int newRing, newPixelInRing;

            return(North(basin, hor, out newRing, out newPixelInRing));
        }