none
关于Virtual Earth中瓦片数据文件组织方式 RRS feed

  • 问题

  • 请问Virtual Earth中瓦片数据文件名比如 ms_1_1_1.png 与 Silverlight map control中 TileSource 中X,Y,ZOOMLEVEL有什么关联?有公式的话当然最好了,谢谢

    2010年4月27日 7:35

答案

  • Virtual Earth?

    现在不是都已经改名为Bing Maps了吗?如果要了解Bing Maps的相关技术点,可以从我参考我博客的关于Bing Maps的系列文章介绍。

     

    Bing Maps相关文章汇总地址:http://www.cnblogs.com/beniao/archive/2010/01/13/1646446.html

    以下为Bing Maps Tile System相关的算法:

    using System;
    using System.Text;
    
    namespace Microsoft.MapPoint
    {
      static class TileSystem
      {
        private const double EarthRadius = 6378137;
        private const double MinLatitude = -85.05112878;
        private const double MaxLatitude = 85.05112878;
        private const double MinLongitude = -180;
        private const double MaxLongitude = 180;
    
    
        /// <summary>
        /// Clips a number to the specified minimum and maximum values.
        /// </summary>
        /// <param name="n">The number to clip.</param>
        /// <param name="minValue">Minimum allowable value.</param>
        /// <param name="maxValue">Maximum allowable value.</param>
        /// <returns>The clipped value.</returns>
        private static double Clip(double n, double minValue, double maxValue)
        {
          return Math.Min(Math.Max(n, minValue), maxValue);
        }
        
        
    
        /// <summary>
        /// Determines the map width and height (in pixels) at a specified level
        /// of detail.
        /// </summary>
        /// <param name="levelOfDetail">Level of detail, from 1 (lowest detail)
        /// to 23 (highest detail).</param>
        /// <returns>The map width and height in pixels.</returns>
        public static uint MapSize(int levelOfDetail)
        {
          return (uint) 256 << levelOfDetail;
        }
    
    
    
        /// <summary>
        /// Determines the ground resolution (in meters per pixel) at a specified
        /// latitude and level of detail.
        /// </summary>
        /// <param name="latitude">Latitude (in degrees) at which to measure the
        /// ground resolution.</param>
        /// <param name="levelOfDetail">Level of detail, from 1 (lowest detail)
        /// to 23 (highest detail).</param>
        /// <returns>The ground resolution, in meters per pixel.</returns>
        public static double GroundResolution(double latitude, int levelOfDetail)
        {
          latitude = Clip(latitude, MinLatitude, MaxLatitude);
          return Math.Cos(latitude * Math.PI / 180) * 2 * Math.PI * EarthRadius / MapSize(levelOfDetail);
        }
    
    
    
        /// <summary>
        /// Determines the map scale at a specified latitude, level of detail,
        /// and screen resolution.
        /// </summary>
        /// <param name="latitude">Latitude (in degrees) at which to measure the
        /// map scale.</param>
        /// <param name="levelOfDetail">Level of detail, from 1 (lowest detail)
        /// to 23 (highest detail).</param>
        /// <param name="screenDpi">Resolution of the screen, in dots per inch.</param>
        /// <returns>The map scale, expressed as the denominator N of the ratio 1 : N.</returns>
        public static double MapScale(double latitude, int levelOfDetail, int screenDpi)
        {
          return GroundResolution(latitude, levelOfDetail) * screenDpi / 0.0254;
        }
    
    
    
        /// <summary>
        /// Converts a point from latitude/longitude WGS-84 coordinates (in degrees)
        /// into pixel XY coordinates at a specified level of detail.
        /// </summary>
        /// <param name="latitude">Latitude of the point, in degrees.</param>
        /// <param name="longitude">Longitude of the point, in degrees.</param>
        /// <param name="levelOfDetail">Level of detail, from 1 (lowest detail)
        /// to 23 (highest detail).</param>
        /// <param name="pixelX">Output parameter receiving the X coordinate in pixels.</param>
        /// <param name="pixelY">Output parameter receiving the Y coordinate in pixels.</param>
        public static void LatLongToPixelXY(double latitude, double longitude, int levelOfDetail, out int pixelX, out int pixelY)
        {
          latitude = Clip(latitude, MinLatitude, MaxLatitude);
          longitude = Clip(longitude, MinLongitude, MaxLongitude);
    
          double x = (longitude + 180) / 360; 
          double sinLatitude = Math.Sin(latitude * Math.PI / 180);
          double y = 0.5 - Math.Log((1 + sinLatitude) / (1 - sinLatitude)) / (4 * Math.PI);
    
          uint mapSize = MapSize(levelOfDetail);
          pixelX = (int) Clip(x * mapSize + 0.5, 0, mapSize - 1);
          pixelY = (int) Clip(y * mapSize + 0.5, 0, mapSize - 1);
        }
    
    
    
        /// <summary>
        /// Converts a pixel from pixel XY coordinates at a specified level of detail
        /// into latitude/longitude WGS-84 coordinates (in degrees).
        /// </summary>
        /// <param name="pixelX">X coordinate of the point, in pixels.</param>
        /// <param name="pixelY">Y coordinates of the point, in pixels.</param>
        /// <param name="levelOfDetail">Level of detail, from 1 (lowest detail)
        /// to 23 (highest detail).</param>
        /// <param name="latitude">Output parameter receiving the latitude in degrees.</param>
        /// <param name="longitude">Output parameter receiving the longitude in degrees.</param>
        public static void PixelXYToLatLong(int pixelX, int pixelY, int levelOfDetail, out double latitude, out double longitude)
        {
          double mapSize = MapSize(levelOfDetail);
          double x = (Clip(pixelX, 0, mapSize - 1) / mapSize) - 0.5;
          double y = 0.5 - (Clip(pixelY, 0, mapSize - 1) / mapSize);
    
          latitude = 90 - 360 * Math.Atan(Math.Exp(-y * 2 * Math.PI)) / Math.PI;
          longitude = 360 * x;
        }
    
    
    
        /// <summary>
        /// Converts pixel XY coordinates into tile XY coordinates of the tile containing
        /// the specified pixel.
        /// </summary>
        /// <param name="pixelX">Pixel X coordinate.</param>
        /// <param name="pixelY">Pixel Y coordinate.</param>
        /// <param name="tileX">Output parameter receiving the tile X coordinate.</param>
        /// <param name="tileY">Output parameter receiving the tile Y coordinate.</param>
        public static void PixelXYToTileXY(int pixelX, int pixelY, out int tileX, out int tileY)
        {
          tileX = pixelX / 256;
          tileY = pixelY / 256;
        }
    
    
    
        /// <summary>
        /// Converts tile XY coordinates into pixel XY coordinates of the upper-left pixel
        /// of the specified tile.
        /// </summary>
        /// <param name="tileX">Tile X coordinate.</param>
        /// <param name="tileY">Tile Y coordinate.</param>
        /// <param name="pixelX">Output parameter receiving the pixel X coordinate.</param>
        /// <param name="pixelY">Output parameter receiving the pixel Y coordinate.</param>
        public static void TileXYToPixelXY(int tileX, int tileY, out int pixelX, out int pixelY)
        {
          pixelX = tileX * 256;
          pixelY = tileY * 256;
        }
    
    
    
        /// <summary>
        /// Converts tile XY coordinates into a QuadKey at a specified level of detail.
        /// </summary>
        /// <param name="tileX">Tile X coordinate.</param>
        /// <param name="tileY">Tile Y coordinate.</param>
        /// <param name="levelOfDetail">Level of detail, from 1 (lowest detail)
        /// to 23 (highest detail).</param>
        /// <returns>A string containing the QuadKey.</returns>
        public static string TileXYToQuadKey(int tileX, int tileY, int levelOfDetail)
        {
          StringBuilder quadKey = new StringBuilder();
          for (int i = levelOfDetail; i > 0; i--)
          {
            char digit = '0';
            int mask = 1 << (i - 1);
            if ((tileX & mask) != 0)
            {
              digit++;
            }
            if ((tileY & mask) != 0)
            {
              digit++;
              digit++;
            }
            quadKey.Append(digit);
          }
          return quadKey.ToString();
        }
    
    
    
        /// <summary>
        /// Converts a QuadKey into tile XY coordinates.
        /// </summary>
        /// <param name="quadKey">QuadKey of the tile.</param>
        /// <param name="tileX">Output parameter receiving the tile X coordinate.</param>
        /// <param name="tileY">Output parameter receiving the tile Y coordinate.</param>
        /// <param name="levelOfDetail">Output parameter receiving the level of detail.</param>
        public static void QuadKeyToTileXY(string quadKey, out int tileX, out int tileY, out int levelOfDetail)
        {
          tileX = tileY = 0;
          levelOfDetail = quadKey.Length;
          for (int i = levelOfDetail; i > 0; i--)
          {
            int mask = 1 << (i - 1);
            switch (quadKey[levelOfDetail - i])
            {
              case '0':
                break;
    
              case '1':
                tileX |= mask;
                break;
    
              case '2':
                tileY |= mask;
                break;
    
              case '3':
                tileX |= mask;
                tileY |= mask;
                break;
    
              default:
                throw new ArgumentException("Invalid QuadKey digit sequence.");
            }
          }
        }
      }
    }

    BLOG:http://beniao.cnblogs.com MSN:beniao@live.cn
    2010年4月27日 13:39