javascript-获取Google Static Maps API的SW和NE角
内容导读
互联网集市收集整理的这篇技术教程文章主要介绍了javascript-获取Google Static Maps API的SW和NE角，小编现在分享给大家，供广大互联网技能从业者学习和参考。文章包含6387字，纯文字阅读大概需要10分钟。
内容图文
我在Unity应用程序中获取Google静态地图的范围时遇到问题.我已经尝试过在stackoverflow上找到多个答案.
我要计算拐角的地图是this.
首先,我尝试将marcelo的代码从javascript转换为C#.将其翻译为以下类.
using System;
using UnityEngine;
public class MercatorProjection
{
static double MERCATOR_RANGE = 256;
Point pixelsOrigin;
double pixelsPerLonDegree;
double pixelsPerLonRadian;
public MercatorProjection()
{
pixelsOrigin = new Point(MERCATOR_RANGE / 2, MERCATOR_RANGE / 2);
pixelsPerLonDegree = MERCATOR_RANGE / 360;
pixelsPerLonRadian = MERCATOR_RANGE / (2 * Math.PI);
}
double bound(double value, double opt_min, double opt_max)
{
if (opt_min != 0)
value = Math.Max(value, opt_min);
if (opt_max != 0)
value = Math.Min(value, opt_max);
return value;
}
double degreesToRadians(double deg)
{
return deg * (Math.PI / 180);
}
double radiansToDegrees(double rad)
{
return rad / (Math.PI / 180);
}
Point fromLatLonToPoint(Coordinates latLon)
{
Point point = new Point();
Point origin = pixelsOrigin;
point.X = origin.X + latLon.Longitude * pixelsPerLonDegree;
double sinY = bound(Math.Sin(degreesToRadians(latLon.Latitude)), -0.9999, 0.9999);
point.Y = origin.Y + 0.5 * Math.Log((1 + sinY) / (1 - sinY)) * -pixelsPerLonRadian;
return point;
}
Coordinates fromPointToLatlon(Point point)
{
Point origin = pixelsOrigin;
Coordinates latLon = new Coordinates();
latLon.Latitude = (point.X - origin.X) / pixelsPerLonDegree;
double latRadians = (point.Y - origin.Y) / -pixelsPerLonRadian;
latLon.Longitude = radiansToDegrees(2 * Math.Atan(Math.Exp(latRadians)) - Math.PI / 2);
return latLon;
}
public void GetCorners(Coordinates center, float zoom, float mapWidth, float mapHeight)
{
double scale = Math.Pow(2, zoom);
Point centerPx = fromLatLonToPoint(center);
Point SWPoint = new Point(centerPx.X - (mapWidth / 2) / scale, centerPx.Y + (mapHeight / 2) / scale);
Coordinates SWLatLon = fromPointToLatlon(SWPoint);
Debug.Log(SWLatLon.Latitude + " " + SWLatLon.Longitude + " " + SWPoint.X + " " + SWPoint.Y);
}
}
因此,起初我仅尝试获取地图的西南角,它非常接近,但是有点偏离.
MercatorProjection.GetCorners(new Coordinates(Coordinates.Longitude, Coordinates.Latitude), 16, 640, 640);
带给我this的结果.
因为有很多人投票,所以我首先尝试翻译marcelo的答案,以至于我在将代码转换为C#的过程中做错了什么.
比我偶然发现peterjb’s answer的人早已将javascript答案翻译为C#,甚至给出了示例,其中他的代码正确地定义了Google静态地图.因此,在下面的类中尝试了peterjb的代码之后；
using System;
public static class GoogleMapsAPI{
static GoogleMapsAPI()
{
OriginX = TileSize / 2;
OriginY = TileSize / 2;
PixelsPerLonDegree = TileSize / 360.0;
PixelsPerLonRadian = TileSize / (2 * Math.PI);
}
public static int TileSize = 256;
public static double OriginX, OriginY;
public static double PixelsPerLonDegree;
public static double PixelsPerLonRadian;
public static double DegreesToRadians(double deg)
{
return deg * Math.PI / 180.0;
}
public static double RadiansToDegrees(double rads)
{
return rads * 180.0 / Math.PI;
}
public static double Bound(double value, double min, double max)
{
value = Math.Min(value, max);
return Math.Max(value, min);
}
//From Lat, Lon to World Coordinate X, Y. I'm being explicit in assigning to
//X and Y properties.
public static Coordinate Mercator(double latitude, double longitude)
{
double siny = Bound(Math.Sin(DegreesToRadians(latitude)), -.9999, .9999);
Coordinate c = new Coordinate(0, 0);
c.X = OriginX + longitude * PixelsPerLonDegree;
c.Y = OriginY + .5 * Math.Log((1 + siny) / (1 - siny)) * -PixelsPerLonRadian;
return c;
}
//From World Coordinate X, Y to Lat, Lon. I'm being explicit in assigning to
//Latitude and Longitude properties.
public static Coordinate InverseMercator(double x, double y)
{
Coordinate c = new Coordinate(0, 0);
c.Longitude = (x - OriginX) / PixelsPerLonDegree;
double latRadians = (y - OriginY) / -PixelsPerLonRadian;
c.Latitude = RadiansToDegrees(Math.Atan(Math.Sinh(latRadians)));
return c;
}
public static MapCoordinates GetBounds(Coordinate center, int zoom, int mapWidth, int mapHeight)
{
var scale = Math.Pow(2, zoom);
var centerWorld = Mercator(center.Latitude, center.Longitude);
var centerPixel = new Coordinate(0, 0);
centerPixel.X = centerWorld.X * scale;
centerPixel.Y = centerWorld.Y * scale;
var NEPixel = new Coordinate(0, 0);
NEPixel.X = centerPixel.X + mapWidth / 2.0;
NEPixel.Y = centerPixel.Y - mapHeight / 2.0;
var SWPixel = new Coordinate(0, 0);
SWPixel.X = centerPixel.X - mapWidth / 2.0;
SWPixel.Y = centerPixel.Y + mapHeight / 2.0;
var NEWorld = new Coordinate(0, 0);
NEWorld.X = NEPixel.X / scale;
NEWorld.Y = NEPixel.Y / scale;
var SWWorld = new Coordinate(0, 0);
SWWorld.X = SWPixel.X / scale;
SWWorld.Y = SWPixel.Y / scale;
var NELatLon = InverseMercator(NEWorld.X, NEWorld.Y);
var SWLatLon = InverseMercator(SWWorld.X, SWWorld.Y);
return new MapCoordinates() { NorthEast = NELatLon, SouthWest = SWLatLon };
}
}
public class MapCoordinates
{
public Coordinate SouthWest { get; set; }
public Coordinate NorthEast { get; set; }
}
public class Coordinate
{
public double Latitude { get; set; }
public double Longitude { get; set; }
public double Y { get { return Latitude; } set { Latitude = value; } }
public double X { get { return Longitude; } set { Longitude = value; } }
public Coordinate(double lng, double lat)
{
Latitude = lat;
Longitude = lng;
}
public override string ToString()
{
return Math.Round(X, 6).ToString() + ", " + Math.Round(Y, 6).ToString();
}
}
我尝试通过调用以下命令再次计算SW和NE角
Coordinates = new Coordinate(51.445691, 5.460318);
var result = GoogleMapsAPI.GetBounds(Coordinates, 16, 640, 640);
Debug.Log("SouthWest: "+result.SouthWest.ToString() + " NorthEast: "+result.NorthEast.ToString());
输出：
SouthWest: 51.438825, 5.453483 NorthEast: 51.452557, 5.467153
西南坐标与我自己的javascript翻译完全相同.因此,由于peterjb在回答中声称他的解决方案适用于比利时的某个地区,因此我在同一地区尝试了该代码.但是,结果还是有点差.
因此,我非常随机地尝试使用尼日利亚的一个名为Kano/Static map的小镇进行计算,令我惊讶的是,西南角非常准确！
输出：
SouthWest: 12.015251, 8.527824 NorthEast: 12.028983, 8.541404
此后,我在世界上其他多个地区进行了尝试,但它往往相距甚远,有时甚至达数百英里.因此,也许尼日利亚的这个小镇只是一个巧合,但我希望有人对我有一个解释和/或解决方案.
解决方法:
正如您所期望的,Coordinate类的构造函数接受(lng,lat)而不是(lat,lng),因此参数的顺序与传递的顺序不同.
我还注意到,Coordinate的ToString覆盖也将打印为(lng,lat),因此如果您希望看到(lat,lng),可能会造成混淆.
只需在静态API中交换这两者即可.
内容总结
以上是互联网集市为您收集整理的javascript-获取Google Static Maps API的SW和NE角全部内容，希望文章能够帮你解决javascript-获取Google Static Maps API的SW和NE角所遇到的程序开发问题。 如果觉得互联网集市技术教程内容还不错，欢迎将互联网集市网站推荐给程序员好友。
内容备注
版权声明：本文内容由互联网用户自发贡献，该文观点与技术仅代表作者本人。本站仅提供信息存储空间服务，不拥有所有权，不承担相关法律责任。如发现本站有涉嫌侵权/违法违规的内容， 请发送邮件至 gblab@vip.qq.com 举报，一经查实，本站将立刻删除。
内容手机端
扫描二维码推送至手机访问。