提供和修改 MapPoint Web Service 地图图像

简介

创建提供地图的 ASP .NET 页面

[C#]
public class MapParams
{
private NameValueCollection requestParams;
private NameValueCollection configParams;
//声明常数来定义 URL 查询字符串中参数
//的名称。
public const string ParamPushpin="PP";
public const string ParamDataSource="DSN";
public const string ParamViewHeightWidth="VHW";
public const string ParamMapWidth="W";
public const string ParamMapHeight="H";
public MapParams(System.Web.UI.Page page)
{
requestParams=page.Request.Params;
configParams=ConfigurationSettings.AppSettings;
}
//如果存在具有页面请求中定义的指定关键字的非空元素，
//则返回此元素；
//如果存在具有 Web.config 文件中指定的关键字的元素，
//就返回这个元素；
//否则，返回空字符串。
public string this[string key]
{
get
{
if (null!=requestParams[key] && requestParams[key].Length>0)
{
return requestParams[key];
}
if (null!=configParams[key] && configParams[key].Length>0)
{
return configParams[key];
}
return String.Empty;
}
}
//将给定的字符串转换为双精度数。如果字符串不是数字
//或者为 Null，返回 0。
private static double GetStringAsDouble(string number)
{
try
{
return Double.Parse(number);
}
catch (ArgumentNullException)
{
return 0;
}
catch (FormatException)
{
return 0;
}
}
//将给定的字符串转换为整数。如果字符串不是数字
//或者为 Null，返回 0。
private static int GetStringAsInt(string number)
{
try
{
return Int32.Parse(number);
}
catch (ArgumentNullException)
{
return 0;
}
catch (FormatException)
{
return 0;
}
}
public string DataSource
{
get
{
return this[ParamDataSource];
}
}
public int MapWidth
{
get
{
return GetStringAsInt(this[ParamMapWidth]);
}
}
public int MapHeight
{
get
{
return GetStringAsInt(this[ParamMapHeight]);
}
}
//返回要呈现的地图的 ViewByHeightWidth 属性。
//具有值的参数的形式为
//Latitude:Longitude:Height:Width。
//如果未定义高度和宽度，它们将采用默认值 1 和 1。
//如果未定义纬度和经度，它们将采用默认值
//0 和 0。
public ViewByHeightWidth View
{
get
{
ViewByHeightWidth retView=new ViewByHeightWidth();
retView.CenterPoint=new LatLong();
string[] vhw=this[ParamViewHeightWidth].Split(new char[] {':'});
if (vhw.Length>=2)
{
retView.CenterPoint.Latitude=GetStringAsDouble(vhw[0]);
retView.CenterPoint.Longitude=GetStringAsDouble(vhw[1]);
}
else
{
retView.CenterPoint.Latitude=0;
retView.CenterPoint.Longitude=0;
}
if (vhw.Length>=4)
{
retView.Height=GetStringAsDouble(vhw[2]);
retView.Width=GetStringAsDouble(vhw[3]);
}
else
{
retView.Height=1;
retView.Width=1;
}
return retView;
}
}
//返回要显示在地图上的图标（图钉）。
//图钉的格式采用的形式为
//Latitude:Longitude:IconName:Label:IconDataSource.
//这里只需要纬度和经度。所有其他参数
//都采用默认值。
//如果查询字符串中未设置图钉，则返回 Null。
public Pushpin Icon
{
get
{
Pushpin retP=new Pushpin();
string[] pp=this[ParamPushpin].Split(new char[] {':'});
if (pp.Length>=2)
{
retP.LatLong=new LatLong();
retP.LatLong.Latitude=GetStringAsDouble(pp[0]);
retP.LatLong.Longitude=GetStringAsDouble(pp[1]);
if (pp.Length>=3)
{
retP.IconName=pp[2];
}
else
{
retP.IconName="32"; //默认为粉红色星号。
}
if (pp.Length>=4)
{
retP.Label=pp[3];
}
if (pp.Length>=5)
{
retP.IconDataSource=pp[4];
}
else
{
retP.IconDataSource="MapPoint.Icons";
}
return retP;
}
else
{
return null;
}
}
}
}

<%@ Page ContentType="image/png" language="c#"
Codebehind="MapServer.aspx.cs" AutoEventWireup="false"
Inherits="SolutionName.MapServer" %>

[C#]
private MapParams mParams;
//按照 mParams 的定义，建立基于查询字符串的地图。
private MapImage GetMap()
{
//创建一个新的 MapSpecification 对象来建立地图。
MapSpecification mapSpec=new MapSpecification();
//直接从 mParams 获取 DataSource。
mapSpec.DataSourceName=mParams.DataSource;
//设置视图。
mapSpec.Views=new MapView[1];
mapSpec.Views[0]=mParams.View;
//设置图钉（如果有）。
Pushpin icon=mParams.Icon;
if (null!=icon)
{
mapSpec.Pushpins=new Pushpin[1];
mapSpec.Pushpins[0]=icon;
}
//设置 MapOptions 对象的属性并
//设置 mParams 的宽度和高度属性。
mapSpec.Options=new MapOptions();
mapSpec.Options.ReturnType=MapReturnType.ReturnImage;
mapSpec.Options.Format=new MapPointService.ImageFormat();
mapSpec.Options.Format.MimeType="image/png";
mapSpec.Options.Format.Width=mParams.MapWidth;
mapSpec.Options.Format.Height=mParams.MapHeight;
//调用 MapPoint Web Service 并返回其相应的
//MapImage 对象。
return RenderService.GetMap(mapSpec)[0];
}
//用 GIF 格式将位图的内容写入流。
private void WriteGifToStream(Bitmap image, Stream outStream)
{
image.Save(outStream,System.Drawing.Imaging.ImageFormat.Gif);
image.Dispose();
}
//用 PNG 格式将位图的内容写入流。
//因为 PNG 无法写入不可寻的流，
//所以使用了一个中间 MemoryStream 对象（可寻）。
private void WritePngToStream(Bitmap image, Stream outStream)
{
MemoryStream writeStream=new MemoryStream();
image.Save(writeStream,System.Drawing.Imaging.ImageFormat.Png);
writeStream.WriteTo(outStream);
image.Dispose();
}
private void Page_Load(object sender, System.EventArgs e)
{
//初始化查询字符串的参数。
mParams=new MapParams(this);
MapImage map=GetMap();
MemoryStream imageStream=new MemoryStream(map.MimeData.Bits);
Bitmap rawBitmap=new Bitmap(imageStream,false);
//修改图像的代码将在此处添加，
//后面的一行代码将被删除。
WritePngToStream(rawBitmap,Response.OutputStream);
}

http://localhost/Mapper/MapServer.aspx?DSN=MapPoint.NA&VHW=47.6:-
122.33:1:1&PP=47.6:-122.33:33:You+are+here&W=400&H=300

<appSettings>
<add key="DSN" value="MapPoint.NA"/>
<add key="W" value="400"/>
<add key="H" value="300"/>
</appSettings>

http://localhost/Mapper/MapServer.aspx?VHW=47.6:-122.33:1:1&PP=47.6:-
122.33:33:You+are+here

修改地图图像

[C#]
Bitmap mapBitmap=new Bitmap(mParams.MapWidth,mParams.MapHeight);
Graphics mapGraphics=Graphics.FromImage(mapBitmap);
mapGraphics.DrawImage(rawBitmap,0,0,mParams.MapWidth,mParams.MapHeight);
rawBitmap.Dispose();
DrawOnMap(mapGraphics);
mapGraphics.Dispose();
WritePngToStream(mapBitmap,Response.OutputStream);

[C#]
private void DrawOnMap(Graphics mapGraphics)
{
Bitmap waterMark=new Bitmap(Request.PhysicalApplicationPath +
System.IO.Path.DirectorySeparatorChar + "store_locator.gif",false);
ImageAttributes attr=new ImageAttributes();
attr.SetColorKey(Color.White,Color.White);
Rectangle rect=new Rectangle(0,0,waterMark.Width,waterMark.Height);
Rectangle rect2=new Rectangle(mParams.MapWidth - waterMark.Width ,
mParams.MapHeight - waterMark.Height , waterMark.Width , waterMark.Height);
mapGraphics.DrawImage(waterMark , rect2 , rect.X , rect.Y ,
rect.Width , rect.Height , GraphicsUnit.Pixel , attr);
}

http://localhost/Mapper/MapServer.aspx?VHW=47.6:-122.33:.25:.25&PP=47.6:-
122.33:33:You+are+here

[C#]
private void DrawOnMap(Graphics mapGraphics)
{
Font font=new Font("Courier New",13,FontStyle.Bold);
string text="Fourth Coffee";
SizeF txtSize=mapGraphics.MeasureString(text,font);
mapGraphics.DrawString(text , font , Brushes.DarkBlue ,
mParams.MapWidth - txtSize.Width , mParams.MapHeight - txtSize.Height);
}

http://localhost/Mapper/MapServer.aspx?VHW=47.6:-122.31:.25:.25&PP=47.6:-
122.31:33:You+are+here

[C#]
private void DrawOnMap(Graphics mapGraphics)
{
//调用 FindNearby 来获取在地图上的显示位置。
FindNearbySpecification findSpec=new FindNearbySpecification();
findSpec.DataSourceName="MapPoint.FourthCoffeeSample";
findSpec.Filter=new FindFilter();
findSpec.Filter.EntityTypeName="FourthCoffeeShops";
findSpec.Options=new FindOptions();
findSpec.Options.Range=new FindRange();
findSpec.Options.Range.Count=500;
findSpec.Options.ResultMask=FindResultMask.LatLongFlag;
findSpec.LatLong=mParams.View.CenterPoint;
findSpec.Distance=50;
FindResults locs=FindService.FindNearby(findSpec);
//将检索出的位置显示为图钉。
//设置字体以显示图钉索引。
Font font=new Font("Arial",6,System.Drawing.FontStyle.Regular);
StringFormat format=new StringFormat();
format.LineAlignment=StringAlignment.Center;
format.Alignment=StringAlignment.Center;
//将每个检索出的纬度和经度转换为其
//在图像系统中的相应坐标。
if (locs!=null && locs.NumberFound>0)
{
LatLong[] latLongs=new LatLong[locs.Results.Length];
for (int i=0;i<latLongs.Length;i++)
{
latLongs[i]=locs.Results[i].FoundLocation.LatLong;
}
PixelCoord[] pixels=RenderService.ConvertToPoint(latLongs ,
mParams.View , mParams.MapWidth , mParams.MapHeight);
int radius=10; //这是图钉的半径。
//在每个位置上绘制一个图钉。
for (int i=0;i<pixels.Length;i++)
{
PixelCoord pixel=pixels[i];
Rectangle rect=new Rectangle(pixel.X-radius,pixel.Y-radius,radius*2,radius*2);
mapGraphics.DrawEllipse(Pens.Lavender,rect);
mapGraphics.FillEllipse(Brushes.Purple , rect.Left+1 , rect.Top+1 ,
rect.Width-2 , rect.Height-2);
mapGraphics.DrawString(i.ToString() , font , Brushes.White ,
rect , format);
}
}
}

http://localhost/Mapper/MapServer.aspx?VHW=47.6:-122.33:50:50

[C#]
//为美国的几个州定义多边形轮廓。
private readonly double[] polyUtah={
37.018358,-114.047383,
36.977346,-109.038487,
40.959254,-109.043443,
40.974323,-111.039242,
41.986081,-111.059671,
41.966724,-114.081657
};
private readonly double[] polyWyoming={
40.974323,-111.039242,
44.993195,-111.061800,
44.983281,-104.064114,
41.006306,-104.053786
};
private readonly double[] polyColorado={
36.977346,-109.038487,
40.959254,-109.043443,
40.982078,-102.063672,
36.984590,-102.047244
};
//将一组多边形的纬度和经度转换为
//地图坐标系统中等同的点的数组。
private Point[][] ConvertPolygonsLatLongToPoints(double[][] polygons)
{
int nbPoints=0;
Point[][] points=new Point[polygons.Length][];
for (int i=0;i<polygons.Length;i++)
{
nbPoints+=polygons[i].Length/2;
points[i]=new Point[polygons[i].Length/2];
}
LatLong[] latLongs=new LatLong[nbPoints];
int idx=0;
foreach (double[] polygon in polygons)
{
for (int i=0;i<polygon.Length;i=i+2)
{
latLongs[idx]=new LatLong();
latLongs[idx].Latitude=polygon[i];
latLongs[idx].Longitude=polygon[i+1];
idx++;
}
}
PixelCoord[] coords=RenderService.ConvertToPoint(latLongs ,
mParams.View , mParams.MapWidth , mParams.MapHeight);
idx=0;
for (int i=0;i<points.Length;i++)
{
for(int j=0;j<points[i].Length;j++)
{
points[i][j]=new Point(coords[idx].X,coords[idx].Y);
idx++;
}
}
return points;
}
//绘制多边形，使用透明度不同的指定颜色来
//表示轮廓线和轮廓线内的区域。
private void OutlinePolygon(Graphics mapGraphics,Point[] poly,Color col)
{
GraphicsPath path=new GraphicsPath();
path.AddPolygon(poly);
SolidBrush brush=new SolidBrush(Color.FromArgb(50,col));
Pen pen=new Pen(Color.FromArgb(100,col),5);
mapGraphics.FillPolygon(brush,poly);
mapGraphics.DrawPolygon(pen,poly);
}
private void DrawOnMap(Graphics mapGraphics)
{
double[][] polygons=new double[3][];
polygons[0]=polyUtah;
polygons[1]=polyWyoming;
polygons[2]=polyColorado;
Point[][] points=ConvertPolygonsLatLongToPoints(polygons);
OutlinePolygon(mapGraphics,points[0],Color.Green);
OutlinePolygon(mapGraphics,points[1],Color.Blue);
OutlinePolygon(mapGraphics,points[2],Color.Red);
}

http://localhost/Mapper/MapServer.aspx?VHW=41:-108:1000:1000

结论