查找由纬度/经度GPS对构成的矩形区域内的坐标 [英] Find coordinates inside a rectangular area constructed by lat/long GPS pairs

问题描述

我从不处理基于位置的数据，因此对于整个GPS编码相关的问题来说，这是非常新的。我有一个问题，我似乎没有找到一种非常有效的方法来解决它，或者可能是我不太确定这种算法。

让你说给出了4个纬度/经度坐标，它们构成了某种矩形区域：（X0，Y0），（X1，Y0），（X0，Y1），（X1，Y1）

  ------------------------ ----------- 
 | b | 
 |一个| 
 | | d 
 | | 
 | c | 
 ----------------------------------- 
e 
  

是否可以找到给定矩形区域内的所有点： a，b，c

区域之外的所有点？ e，d

我可以轻松地构建2D矩阵来做到这一点，但这仅在坐标为整数，但是对于经纬度/经度对，坐标通常是浮点数，我们不能用它来构建2D表。

有什么好主意吗？

编辑1：

此射线广播算法？

解决方案

如果矩形是轴对齐的，这是用于GPS坐标的好算法吗？

解决方案

@Eyal的答案是正确的答案（您实际上不需要8个值，但4个就足够了。）

如果处理旋转的矩形（适用于任何矩形）四边形），则采用射线法是合适的：考虑穿过测试点的水平线Y = Yt并找到与测试点交叉的边缘（上方一个端点，下方一个端点）。将有0或2个这样的边。如果是0，则您在外面。否则，计算这些边缘与直线的交点的横坐标。如果0或2交点位于测试点的左侧，则您在外面。

  Xi = Xt +（Yt-Y0 ）（X1-X0）/（Y1-Y0）
  

I've never deal much with location-based data, so very much new to the whole GPS coding related questions. I have a problem that I don't seem to find a very efficient way in solving it or maybe there's an algorithm that I'm not too sure.

Let said you have given 4 lat/long coordinates which construct some kind of a rectangular area: (X0, Y0), (X1, Y0), (X0, Y1), (X1, Y1)

-----------------------------------
|                   b             |
|   a                             |
|                                 | d
|                                 |
|     c                           |
-----------------------------------
             e

Is there a way to find all the point that are inside the given rectangular area : a, b, c
And all the points outside of the area? e, d

I can easily to construct a 2D matrix to do this, but that's only if the coordinates are in integer, but with lat/long pairs, the coordinates are usually in float numbers which we cannot use it to construct a 2D table.

Any cool ideas?

Edited 1:

What about this Ray-casting algorithm? Is this a good algorithm to be used for GPS coordinates which is a float number?

解决方案

If your rectangle is axis-aligned, @Eyal's answer is the right one (and you actually don't need 8 values but 4 are enough).

If you deal with a rotated rectangle (will work for any quadrilateral), the ray-casting method is appropriate: consider the horizontal line Y=Yt through your test point and find the edges that cross it (one endpoint above, one endpoint below). There will be 0 or 2 such edges. In case 0, you are outside. Otherwise, compute the abscissas of the intersections of these edges with the line. If 0 or 2 intersection are on the left of the test point, you are outside.

Xi= Xt + (Yt - Y0) (X1 - X0) / (Y1 - Y0)

这篇关于查找由纬度/经度GPS对构成的矩形区域内的坐标的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！