blocks|key|1924811|text|选项1:通过切换到支持GeoIP的数据库或使用MySQL的基本GeoIP功能，在数据库上执行计算。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1924812|选项2:在数据库上进行计算:您使用的是MySQL，因此下面的存储过程应该会有所帮助|1924813|CREATE+FUNCTION+distance+(latA+double,+lonA+double,+latB+double,+LonB+double)
++++RETURNS+double+DETERMINISTIC
BEGIN
++++SET+@RlatA+=+radians(latA);
++++SET+@RlonA+=+radians(lonA);
++++SET+@RlatB+=+radians(latB);
++++SET+@RlonB+=+radians(LonB);
++++SET+@deltaLat+=+@RlatA+-+@RlatB;
++++SET+@deltaLon+=+@RlonA+-+@RlonB;
++++SET+@d+=+SIN(@deltaLat/2)+*+SIN(@deltaLat/2)+%2B
++++COS(@RlatA)+*+COS(@RlatB)+*+SIN(@deltaLon/2)*SIN(@deltaLon/2);
++++RETURN+2+*+ASIN(SQRT(@d))+*+6371.01;
END//|code-block|syntax|javascript|1924814|如果你的数据库中有一个纬度和经度的索引，你可以减少需要计算的计算次数，方法是在PHP中创建一个初始边界框(+$minLat，$maxLat，$minLong和$maxLong)，并基于此将行限制为条目的子集(其中纬度在$minLat和$maxLat之间，经度在$minLong和$maxLong之间)。然后，MySQL只需要对该行的子集执行距离计算。|1924815|如果您只是使用skv提供的SQL语句(或存储过程来计算距离)，那么SQL仍然需要查看数据库中的每条记录，并计算数据库中每条记录的距离，然后才能决定是返回该行还是丢弃该行。|1924816|因为计算的执行速度相对较慢，所以如果您可以减少需要计算的行集，消除明显超出所需距离的行，这样我们只对较少的行数执行开销较大的计算，这会更好。|1924817|考虑到你正在做的基本上是在地图上画一个圆，以你的初始点为中心，并有一个距离半径；然后这个公式简单地识别出哪些行属于这个圆……但它仍然需要检查每一行。|1924818|使用边界框就像在地图上绘制一个正方形，首先在离中心点适当的距离上画出左、右、上和下的边。然后，我们的圆将在该框中绘制，圆上的最北点、最东点、最南点和最西点将与框的边界接触。一些行将落在该框之外，因此SQL甚至不会费心计算这些行的距离。它只计算那些落在边界框内的行的距离，以查看它们是否也落在圆内。|1924819|在PHP中，我们可以使用一个非常简单的计算方法，根据距离计算出最小和最大纬度和经度，然后在SQL语句的WHERE子句中设置这些值。这实际上是我们的盒子，任何落在盒子之外的东西都会被自动丢弃，而不需要实际计算它的距离。|1924820|在Movable+Type+website上有一个很好的解释(用PHP代码)，这应该是任何计划用PHP做任何GeoPositioning工作的人的必备读物。|offset|length|1924821|entityMap|0|LINK|mutability|MUTABLE|url|http://www.movable-type.co.uk/scripts/latlong-db.html^0|0|0|0|0|0|0|0|0|0|1|K|0|0^^$0|@$1|2|3|4|5|6|7|16|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|17|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|18|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|19|8|@]|9|@]|A|$]]|$1|K|3|L|5|6|7|1A|8|@]|9|@]|A|$]]|$1|M|3|N|5|6|7|1B|8|@]|9|@]|A|$]]|$1|O|3|P|5|6|7|1C|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|1D|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|1E|8|@]|9|@]|A|$]]|$1|U|3|V|5|6|7|1F|8|@]|9|@$W|1G|X|1H|1|1I]]|A|$]]|$1|Y|3|-4|5|6|7|1J|8|@]|9|@]|A|$]]]|Z|$10|$5|11|12|13|A|$14|15]]]]

Option 1:
Do the calculation on the database by switching to a database that supports GeoIP, or use MySQLs basic GeoIP features.

Option 2:
Do the calculation on the database: you're using MySQL, so the following stored procedure should help

<pre><code>CREATE FUNCTION distance (latA double, lonA double, latB double, LonB double)
 RETURNS double DETERMINISTIC
BEGIN
 SET @RlatA = radians(latA);
 SET @RlonA = radians(lonA);
 SET @RlatB = radians(latB);
 SET @RlonB = radians(LonB);
 SET @deltaLat = @RlatA - @RlatB;
 SET @deltaLon = @RlonA - @RlonB;
 SET @d = SIN(@deltaLat/2) * SIN(@deltaLat/2) +
 COS(@RlatA) * COS(@RlatB) * SIN(@deltaLon/2)*SIN(@deltaLon/2);
 RETURN 2 * ASIN(SQRT(@d)) * 6371.01;
END//
</code></pre>

If you have an index on latitude and longitude in your database, you can reduce the number of calculations that need to be calculated by working out an initial bounding box in PHP ($minLat, $maxLat, $minLong and $maxLong), and limiting the rows to a subset of your entries based on that (WHERE latitude BETWEEN $minLat AND $maxLat AND longitude BETWEEN $minLong AND $maxLong). Then MySQL only needs to execute the distance calculation for that subset of rows.

If you're simply using the SQL statement provided by skv (or a stored procedure to calculate the distance) then SQL still has to look through every record in your database, and to calculate the distance for every record in your database before it can decide whether to return that row or discard it.

Because the calculation is relatively slow to execute, it would be better if you could reduce the set of rows that need to be calculated, eliminating rows that will clearly fall outside of the required distance, so that we're only executing the expensive calculation for a smaller number of rows.

Considering that what you're doing is basically drawing a circle on a map, centred on your initial point, and with a radius of distance; then the formula simply identifies which rows fall within that circle... but it still has to checking every single row.

Using a bounding box is like drawing a square on the map first with the left, right, top and bottom edges at the appropriate distance from our centre point. Our circle will then be drawn within that box, with the Northmost, Eastmost, Southmost and Westmost points on the circle touching the borders of the box. Some rows will fall outside that box, so SQL doesn't even bother trying to calculate the distance for those rows. It only calculates the distance for those rows that fall within the bounding box to see if they fall within the circle as well.

Within PHP, we can use a very simple calculation that works out the minimum and maximum latitude and longitude based on our distance, then set those values in the WHERE clause of your SQL statement. This is effectively our box, and anything that falls outside of that is automatically discarded without any need to actually calculate its distance.

There's a good explanation of this (with PHP code) on the <a href="http://www.movable-type.co.uk/scripts/latlong-db.html" rel="nofollow">Movable Type website</a> that should be essential reading for anybody planning to do any GeoPositioning work in PHP.

blocks|key|1977588|text|你可以在机场周围使用六边形网格和螺旋搜索。下面是一个包含相邻磁贴的示例：Optimizing+search+through+large+list+of+lat/long+coords+to+find+match|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1977589|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/questions/18139602/optimizing-search-through-large-list-of-lat-long-coords-to-find-match/18145430#18145430^0|10|1X|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

You can use a hexagon grid and spiral search around the airport. Here is an example with adjacent tiles: <a href="https://stackoverflow.com/questions/18139602/optimizing-search-through-large-list-of-lat-long-coords-to-find-match/18145430#18145430">Optimizing search through large list of lat/long coords to find match</a>

First off, I know that there are answers to questions pertaining this function and i looked through most of them and i could find the answer that I was looking for. What I am trying to do can quite simply be explain in an image:

<a href="http://stokemandevelopment.com/pictures/image1.JPG" rel="nofollow noreferrer">image diagram of php distance function http://stokemandevelopment.com/pictures/image1.JPG</a>

Now let add some narrative to this image. What I am trying to do is, in MySQL, calculate the distance from the airport to all the airports in my database, and if they fall in between Radius A and Radius B, add them to an array from me to do something with at a later time. 

<pre><code>function distance($lat1, $lon1, $lat2, $lon2, $unit) {
 $theta = $lon1 - $lon2;
 $dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2)) + cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta));
 $dist = acos($dist);
 $dist = rad2deg($dist);
 $miles = $dist * 60 * 1.1515;
 $unit = strtoupper($unit);

 if ($unit == "K") {
 return ($miles * 1.609344);
 } else if ($unit == "N") {
 return ($miles * 0.8684);
 } else {
 return $miles;
 }
}
</code></pre>

THis is what I currently use to do my caluclations but it is in php, and is extremely slow. I am looking to upgrade the code so that the mysql server does the calculations. I am also trying to do this all in PHP PDO. If anybody can help me, it will be greatly appreciated.

PHP Distance based on min and max radius

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

文章

问答

视频

学习中心

腾讯云实验室

直播

竞赛

腾讯云代码分析专区

腾讯iOA零信任安全管理系统专区

腾讯云架构师技术同盟交流圈

腾讯云数据库专区

腾讯云顾问专区

腾讯云原生专区

腾讯混元专区

腾讯云TCE专区

腾讯云Lighthouse专区

腾讯云HAI专区

腾讯云Edgeone专区

腾讯云存储专区

腾讯云智能专区

腾讯轻联专区 

腾讯云开发专区

TAPD专区

腾讯轻量云游戏服专区

腾讯云最具价值专家

腾讯云架构师技术同盟

腾讯云创作之星

腾讯云开发者先锋

腾讯云代码助手

云原生构建

TAPD 敏捷项目管理

Cloud Studio

SDK中心

API中心

命令行工具

涵盖代码开发、场景应用、自动测试全流程，助你从零构建专属AI助手

一站式MCP教程库，解锁AI应用新玩法

首先，我知道有关于这个函数的问题的答案，我浏览了其中的大多数，我可以找到我正在寻找的答案。我想要做的事情可以很简单地用图片来解释：现在，让我们在这张图片中添加一些叙述。我正在尝试做的是，在MySQL中，计算从机场到我数据库中所有机场的距离，如果它们落在半径A和半径B之间，将它们添加到我的数组中，以便以后执行某些操作。f...

问基于最小和最大半径的PHP距离
EN

Stack Overflow用户

社区

活动

圈层

关于

腾讯云开发者

热门产品

热门推荐

更多推荐

问基于最小和最大半径的PHP距离EN