如何从地图Api网络服务中除印度以外的地图中删除其他国家..对这一挑战的任何想法..？ [英] How to remove other country from map except India in map Api web service..Any idea about this challenge..?

问题描述

嘿天才我对你有挑战

我想在静态地图虚构中显示印度的地图（For Bing Map Api）

这是你理解的链接

http://dev.virtualearth.net/REST/v1/Imagery/Map/Road/Routes？ mapSize = 700600&安培; wp.0 =新德里，印度; 64; 1安培; WP.1 =斋浦尔，印度拉贾斯坦邦; 64; 2及WP.2 =阿格拉，UTT AR％20Pradesh，印度; 64; 3及WP.3 =占西，％20Madhya％20Pradesh，印度; 64; 4&安培; WP.4 =奥尔恰，中央％20Pradesh，印度; 64; 5&安培; WP.5 =克久拉霍，中央％20Pradesh，印度; 64; 6&安培; WP.6 =瓦拉纳西，北方邦％20Pradesh，印度; 64; 7&安培; WP.7 = Kolkata，西％20Bengal，印度; 64; 8&安培; WP.8 =奈，泰米尔语％20Nadu ，印度; 64; 9&安培; WP.9 =普兰，TAMILNADU，印度; 64; 10&安培; WP.10 =在Kanchipuram，TAMILNADU，印度; 64; 11&安培; WP.11 =马杜赖，TAMILNADU，印度; 64; 12&安培;键= AsgtkL4EokKmLiZdxC0XSzju3l5eWKCG8t5F9gzg8BuOLh91Py3u-e6PzrHRxwB8 [ ^ ]

在这里我只想显示印度而不是其他国家..所以任何人都有这个想法然后请告诉我....

解决方案

API本身不提供此功能，但有一种解决方法：



- 获取国家边界的坐标。您可以从 http://www.gadm.org/ 下载坐标[ ^ ]

- 将它们放入PointF数组中

 PointF [] selectedArea = {
  new  PointF（ 1  .12345f， 3  .45678f），
 ... 
} 

- 翻译中的坐标数组到可见图块上的点，这将给你一个Point []。我不太了解这一部分，但此页 [ ^ ]有一个关于像素坐标的部分，显示确切的代码行从坐标转换为像素。我把它贴在这里作为参考（在VB中）：

 sinLatitude = sin（纬度* pi / 180）
 pixelX =（（经度+  180 ）/  360 ）*  256  *（2 ^等级）
 pixelY =（ 0 。 5   -  log（（ 1  + sinLatitude）/（ 1   -  sinLatitude））/（ 4  * pi））*  256  *（2 ^ level）

- 使用这些点创建多边形路径

 GraphicsPath polygonPath =  new  GraphicsPath（）; 
 polygonPath.AddPolygon（points）; 

- 为整个图块创建一个区域，如下所示（图块大小取决于详细程度，那里是上面链接中的表格，用于不同缩放级别的图块大小

区域区域= 新 Region（ new 矩形（ 0 ， 0  ， 256 ， 256 ））; 

- 排除刚刚创建的区域。

 region.Exclude（polygonPath）; 

- 填写区域这将掩盖国界以外的一切

 graphics.FillRegion（Brushes.Black，region）; 

为了使它看起来更漂亮，您可以决定使用点数组绘制一条线以清楚地标记国家边界。

 graphics.DrawLines（
  new  System.Drawing.Pen（System.Drawing.Color.FromArgb（ 255 ， 255 ， 0 ， 0 ）， 3 ），
分）; 

hey genius I have a challenge for you
I want to show only India's map in static map imaginary(For Bing Map Api)
this is link for your understanding
http://dev.virtualearth.net/REST/v1/Imagery/Map/Road/Routes?mapSize=700,600&wp.0=Delhi,India;64;1&wp.1=Jaipur,Rajasthan,India;64;2&wp.2=Agra,Uttar%20Pradesh,India;64;3&wp.3=Jhansi,%20Madhya%20Pradesh,India;64;4&wp.4=Orchha,Madhya%20Pradesh,India;64;5&wp.5=Khajuraho,Madhya%20Pradesh,India;64;6&wp.6=Varanasi,Uttar%20Pradesh,India;64;7&wp.7=Kolkata,West%20Bengal,India;64;8&wp.8=Chennai,Tamil%20Nadu,India;64;9&wp.9=Mahabalipuram,TamilNadu,India;64;10&wp.10=Kanchipuram,TamilNadu,India;64;11&wp.11=Madurai,TamilNadu,India;64;12&key=AsgtkL4EokKmLiZdxC0XSzju3l5eWKCG8t5F9gzg8BuOLh91Py3u-e6PzrHRxwB8[^]
In this I only want to display India not other country..so any one have idea about this then please tell me....

解决方案

The API itself doesn't offer this functionality, however there is a workaround:

- Get the coordinates for the country border. You can download the coordinates from http://www.gadm.org/[^]
- Put them in a PointF array

PointF[] selectedArea = {
  new PointF(1.12345f, 3.45678f),
  ...
}

- Translate the coordinates in the array to points on your visible tile, this will give you a Point[]. I don't know that part by hard, but this page[^] has a section on Pixel Coordinates showing you the exact lines of code to translate from coordinates to pixels. I paste it here for reference (in VB):

sinLatitude = sin(latitude * pi/180)
pixelX = ((longitude + 180) / 360) * 256 * (2^level)
pixelY = (0.5 – log((1 + sinLatitude) / (1 – sinLatitude)) / (4 * pi)) * 256 * (2^level)

- Create a polygon path using these points

GraphicsPath polygonPath = new GraphicsPath();
polygonPath.AddPolygon(points);

- Create a region for the entire tile, something like this (the tile size depends on the level of detail, there is a table in the link above for tile sizes for different 'zoom levels'

Region region = new Region(new Rectangle(0, 0, 256, 256));

- Exclude the area you just created.

region.Exclude(polygonPath);

- Fill the region with a color. This will mask out everything outside the country borders

graphics.FillRegion(Brushes.Black, region);

To make it look nicer, you may decide to draw a line using the points array to clearly mark the country border.

graphics.DrawLines(
new System.Drawing.Pen(System.Drawing.Color.FromArgb(255, 255, 0, 0), 3),
points);

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