找到一个离源的距离的坐标 [英] finding a coordinate at some distance from the source
问题描述
用户触摸地图,触摸坐标。现在我必须找到一些距离东约5公里的坐标,另一个距南部约5公里。我已经通过谷歌搜索,但找不到任何算法。
我不知道这是这个问题的正确的地方,或者我需要找到一些其他可以找到与数学有关的问题的部分。
任何帮助都会很棒。
感谢
Pankaj
如果地球的圆周是C,那么给定点南部d公里的点在南方是360度/摄氏度。东面d公里的点在东方是360 * d /(C * cos(纬度))度。
所以如果地球的圆周是40075.04公里,移动距离南部5公里,您将从纬度中减去0.0449,并使用相同的经度。要向东移动5公里,您将使用相同的纬度,并向经度添加0.0449 / cos(纬度)。
I am working on an iPhone app where I need to find some coordinares at some distance from a given point. The user touches the map and I get coordinates at the touch. Now I have to find some coordinates which are about 5 km away towards east and another one about 5km down to south. I have searched over google but could not find any algo for it.
I am not sure this is correct place for this question or i need to find some other section where I can find questions related to maths.
Any help will be great.
Thanks
Pankaj
If Earth's circumference is C, the point at d kilometers to south of a given point is 360*d/C degrees to the south. The point at d kilometers to east is 360*d/(C*cos(latitude)) degrees to the east.
So if Earth's circumference is 40075.04 km, to move 5 km to the south you would subtract 0.0449 from the latitude and use the same longitude. To move 5 km to the east you would use the same latitude and add 0.0449/cos(latitude) to the longitude.
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