GMap.Net中使用高德地圖

GMap.Net是.Net下一個地圖控件，可以基於Http協議加載各個公司的地圖，如Google，Bing，ArcGIS的，主要原理是通過解析各個公司的地圖服務的URL，傳入相應的參數得到對應的切片底圖（Tiled map），如一個高德地圖的GMapProvider的實現如下：

using System;
using GMap.NET;
using GMap.NET.MapProviders;
using GMap.NET.Projections;

namespace GMapProvidersExt
{
    public abstract class AMapProviderBase : GMapProvider
    {
        public AMapProviderBase()
        {
            MaxZoom = null;
            RefererUrl = "http://www.amap.com/";
            //Copyright = string.Format("©{0} 高德 Corporation, ©{0} NAVTEQ, ©{0} Image courtesy of NASA", DateTime.Today.Year);    
        }

        public override PureProjection Projection
        {
            get { return MercatorProjection.Instance; }
        }

        GMapProvider[] overlays;
        public override GMapProvider[] Overlays
        {
            get
            {
                if (overlays == null)
                {
                    overlays = new GMapProvider[] { this };
                }
                return overlays;
            }
        }
    }

    public class AMapProvider : AMapProviderBase
    {
        public static readonly AMapProvider Instance;
   
        readonly Guid id = new Guid("EF3DD303-3F74-4938-BF40-232D0595EE88");
        public override Guid Id
        {
            get { return id; }
        }

        readonly string name = "AMap";
        public override string Name
        {
            get
            {
                return name;
            }
        }

        static AMapProvider()
        {
            Instance = new AMapProvider();
        }

        public override PureImage GetTileImage(GPoint pos, int zoom)
        {
            try
            {
                string url = MakeTileImageUrl(pos, zoom, LanguageStr);
                return GetTileImageUsingHttp(url);
            }
            catch (Exception ex)
            {
                return null;
            }
        }

        string MakeTileImageUrl(GPoint pos, int zoom, string language)
        {
            var num = (pos.X + pos.Y) % 4 + 1;
            //string url = string.Format(UrlFormat, num, pos.X, pos.Y, zoom);
            string url = string.Format(UrlFormat, pos.X, pos.Y, zoom);
            return url;
        }

        //static readonly string UrlFormat = "http://webrd04.is.autonavi.com/appmaptile?x={0}&y={1}&z={2}&lang=zh_cn&size=1&scale=1&style=7";
        static readonly string UrlFormat = "http://webrd01.is.autonavi.com/appmaptile?lang=zh_cn&size=1&scale=1&style=7&x={0}&y={1}&z={2}";
    }
}

如下為高德地圖的顯示：

通過類似的辦法，可以實現加載Google、騰訊的地圖，百度的地圖也可以加載，但是因為百度采用自己的加偏算法（BD-09），導致加載的地圖顯示偏差大，當在不同的地圖間切換時，無法正確顯示。

 

引自：http://www.cnblogs.com/luxiaoxun/p/3802559.html