问题描述
我使用Phonegap和JQuery创建了一个移动应用程序。
I am creating a mobile app using Phonegap and JQuery.
应用程序收集用户的经度和纬度，并将它们存储在数据库中（使用PHP脚本 - Web服务），并且使用一些算法检测是否存在业务。我需要的是从数据库中获取所有的经度和纬度值，它们彼此接近，例如在同一条街道/ 200m范围内。
The app collects the longitude and latitude of users and stores them in a database (using a PHP script - web service), and with some algorithm it detects whether there is traffic or not. What I need is to grab all the longitude and latitude values from the database which are close to each other, say in the same street/200m range.
假设你在数据库中有一个5 lon / lat的列表，它们在彼此附近（在同一条街道A），3 lon /其他在某些街道B，和其他一些代表用户随机在其他街道。任何人都能告诉我怎样才能检测到彼此相邻的Lon / lat值？我将它们作为单独的值存储在MySQL数据库中，即一个字段用于经度，另一个用于纬度。
Lets say you have a list in the database with 5 lon/lat which are near each other (in the same street A), 3 lon/lat which are near each other in some Street B, and some other representing users randomly in other streets. Can anyone tell me how I can detect the lon/lat values that are near each other? The values I am storing them as separate values in the MySQL database, ie one field for longitude and another for latitude.
一旦我获得了lon /其他，那么我需要找到街道A中的用户之间的中心点，以及街道B中的用户标记为交通拥堵（基于一些其他检测）。
Once I obtain the lon/lat which are near each other, then I would need to find the center point between the users in street A, and users in street B to mark as a traffic congestion (based on some other detections).
推荐答案
你应该看看Haversine公式。
You should look into the Haversine formula. Please see below:
SELECT id, (3959 * acos( cos( radians(37) ) * cos( radians( lat ) ) * cos( radians( lng ) - radians(-122) ) + sin( radians(37) ) * sin( radians( lat ) ) ) ) AS distance
FROM markers
HAVING distance < 25
ORDER BY distance;
这将返回输入long / lat对25英里内的所有记录。
This will return all records that are within 25 miles of the input long / lat pair.
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