[RESOLVED] make array with distance, then sort

djalecc

I'm a little stuck... confused, eyes poping out sort of thing... and was wondering if anyone could throw some light on this...

I'm pulling results from my database using a distance from a Lat & Lng, I get the results within the distance fine, my only problem is then sorting the results according to the distance.

As distance is calculated after the query, and not within it, I assume I have to make an array of the results, adding my distance calculation to the results, then sorting on the distance?

so...

The point that we start from

$lat = 52.12345;
$lng = -2.12345;
$set_distance=0.6;

The query to get users near to that point

$result = mysql_query("SELECT * FROM users WHERE (lat > '$lat' - '$set_distance') AND (lat < '$lat' + '$set_distance') AND (lon > '$lon' - '$set_distance') AND (lon < '$lon' + '$set_distance') AND username = '$user' LIMIT 50", $link);

This works fine and returns the results I expect, now I just work out the distance between the start point and the current result in the loop.

while($row=mysql_fetch_array($result)) {
$lat2=$row[lat];
$lon2=$row[lon];
$distance_from_point = getDistanceBetweenPointsNewMiles($lat, $lon, $lat2, $lon2);// returns the distance between the 2 points
mysql_free_result($result);

So I have the results I need, and the distance I need, I just need to display them in the correct ORDER i.e. closest distance first.

I haven't quite mastered arrays yet, and dispite my best efforts am a little stuck! Either that or I just need to go to bed and sleep on it :o

NogDog

One way:

$data = array(); // this will store the results
while($row=mysql_fetch_assoc($result)) {
   $row['distance'] = 
      getDistanceBetweenPointsNewMiles($lat, $lon, $row['lat'], $row['lon']);
   $data[] = $row; // add this result row to the array
}
usort($data, create_function('$a,$b', 'return $a["distance"] - $b["distance"];'));
// subtract $a["distnace"] from $b["distance"] to reverse the sort

foreach($data as $value)
{
   // output elements of $value as desired for this row
}

djalecc

ace!!!

thanks man, that sorted it all out!

😃