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POQueries to find places within a given lat/lng
 

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    <p>So I'm trying to display lists of places within a range of the given lat/lng. I have no problem with this:</p> <p>Places within one mile (list of places...)</p> <p>Using something like</p> <pre><code>SELECT * FROM places WHERE lat &lt; $latmax AND lat &gt; $latmin AND lng &lt; $lngmax AND lng &gt; $lngmin </code></pre> <p>But then I want to list places within two miles, BUT not within one mile -- that is, I don't want to repeat the results from the first query.</p> <p>Here's one version of what I've tried:</p> <pre><code>$milesperdegree = 0.868976242 / 60.0 * 1.2; // 1 mile -- this works $degrees = $milesperdegree * 1; $latmin = $lat - $degrees; $latmax = $lat + $degrees; $lngmin = $lng - $degrees; $lngmax = $lng + $degrees; $query = "SELECT * FROM places WHERE lat &lt; $latmax AND lat &gt; $latmin AND lng &lt; $lngmax AND lng &gt; $lngmin"; // 2 miles -- this doesn't work $degrees_2 = $milesperdegree * 2; $latmin_2 = $lat - $degrees_2; $latmax_2 = $lat + $degrees_2; $lngmin_2 = $lat - $degrees_2; $lngmax_2 = $lat + $degrees_2; $query = "SELECT * FROM places WHERE "; $query .= "lat BETWEEN $latmax AND $latmax_2 AND lng BETWEEN $lngmax AND $lngmax_2 OR "; $query .= "lat BETWEEN $latmin AND $latmin_2 AND lng BETWEEN $lngmin AND $lngmin_2 OR "; $query .= "lat BETWEEN $latmax AND $latmax_2 AND lng BETWEEN $lngmin AND $lngmin_2 OR "; $query .= "lat BETWEEN $latmin AND $latmin_2 AND lng BETWEEN $lngmax AND $lngmax_2"; </code></pre> <p>That's not doing it. I'm guessing it's just some logic I can't wrap my head around on Sunday afternoon, but I'm probably doing something else wrong too. Any input is greatly appreciated.</p>
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    1. CODo you realize that this script just makes a box around the point (instead of a circle)? Also, $milesperdegree is a function (mathematically speaking) of latitude. There's a nice script for this - although in JavaScript - [link](http://www.fas.org/news/reference/calc/degree.html)
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    2. COI did not realize the circle/square bit. And I guess the longitude variables would be $lng +/- x miles, rather than $milesperdegree?
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    3. COAs Earth is not a perfect sphere, the length of a degree is not fixed. If your scripts operates just on a small area (like a city), you can work with an average **for that area**. Otherwise more math is needed for precision. See [latitude](http://en.wikipedia.org/wiki/Latitude#Degree_length) and [longitude](http://en.wikipedia.org/wiki/Longitude#Degree_length) in Wikipedia.
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