东向北纬至经度 [英] Easting northing to latitude longitude

问题描述

我有东/北格式的位置坐标，但我需要将其转换为合适的经纬度，以便将它居中放置在bing地图中。任何公式或细节如何将easting / northing转换为lat / lon？编辑：更具体地说，我需要将SVY21坐标转换为WGS84

解决方案

Eastings和northings分别是基点的东部和北部的距离。基点通常是经度和纬度，东和北通常以米或英尺表示。然而，东向和北向通常会抵消一个特定的值，使它们成为正值，并允许它们表示基点的西部和南部。

通常，转换从一个坐标系统到另一个坐标系统并不简单，因为两者都可能有不同的椭球体（地球模型）和基准面。据我所知，从一个坐标系转换到另一个坐标系的公式相当复杂。

SVY21 使用与WGS84完全相同的基准面和椭球体，使得任务更简单。在SVY21中，eastings和northings的基点是皮尔斯水库的Base 7 ，1度。 22分钟。 02.9154秒北和103度。 49分31.9752秒（即，纬度约为1.3674765度，经度约为103.8255487度;然而，众所周知的文本分别使用1.3666度和103.8333度）。东向偏移量为28001.642米，北向偏移量为38744.572米。 EPSG代码是3414.我会假定你的eastings和northings以米为单位。

由于SVY21使用与WGS84相同的系统，所以你只需要：

• 用相应的偏移值减去东和北。 （这些值将以米为单位）。
  
• 通过找到给定基点的目标点，东向的绝对值和90度方位来查找给定点的经度如果东正面是正面的，或270度，如果是负面的。 此链接包含相关公式。 （对于这种计算，可以使用余弦的球面定律，如目标点给定的距离和方位从起点开始一节中给出的，或者更精确的 li>
  
• 找到给定点的纬度，方法是找到给定基点的目标点，北向的绝对值，如果北向为正，则方位为0度，如果是北向，则为180度负数。

I've got coordinates of location in easting/northing format but I need to convert it to proper lat long to center it in bing maps. Any formula or details how to convert easting/northing to lat/lon?

EDIT: To be more specific, I need to convert SVY21 coordinates to the to WGS84

解决方案

Eastings and northings are distances east and north, respectively, of a base point. The base point is usually a latitude and longitude, and eastings and northings are normally expressed in meters or feet. The easting and northing, however, is usually offset a particular value to make them positive and allow them to express places west and south of the base point.

In general, converting from one coordinate system to another is not simple, since both may have different ellipsoids (Earth models) and datums. As I understand, the formulas for converting from one coordinate system to another are rather complex.

SVY21, however, uses the exact same datum and ellipsoid as WGS84, making the task simpler. In SVY21, the base point for eastings and northings is Base 7 at Pierce Reservoir, 1 deg. 22 min. 02.9154 sec. north and 103 deg. 49 min 31.9752 sec. east (that is, a latitude of about 1.3674765 degrees and a longitude of about 103.8255487 degrees; the well known text, however, uses 1.3666... degrees and 103.8333... degrees, respectively). The offset for the easting is 28001.642 meters, and the offset for the northing is 38744.572 meters. The EPSG code is 3414. I will assume your eastings and northings are expressed in meters.

Since SVY21 uses the same system as WGS84, all you have to do is:

• Subtract the easting and northing by their respective offset values. (The values will be in meters.)
• Find the longitude of the given point by finding the destination point given the base point, the absolute value of the easting, and the bearing of 90 degrees if the easting is positive, or 270 degrees if it's negative. This link contains the relevant formulas. (For this calculation, you can use either the spherical law of cosines, as given in the section "Destination point given distance and bearing from start point", or the more accurate Vincenty's direct formula. The first linked page, however, doesn't use the Haversine formula for this calculation.)
• Find the latitude of the given point by finding the destination point given the base point, the absolute value of the northing, and the bearing of 0 degrees if the northing is positive, or 180 degrees if it's negative.

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