php lat long radius search from zip code

Question

been reading up on this in stack overflow and other places, and tried to put together some coding to do the job I need. I will have a zip code (for test purposes it is fixed at 28752) and I want the page to give me locations within 50 miles of the zip code. Most of what I read is way over my head, but I cobbled together the following, and to the best of my limited knowledge it should work (giving me a list of records within the parameters), but it isn't.

First of all I set up the parameters using the following...

$zipcode="28752";
$url = "http://maps.googleapis.com/maps/api/geocode/json?address=".$zipcode."&sensor=false";
$details=file_get_contents($url);
$result = json_decode($details,true);

$lat=$result['results'][0]['geometry']['location']['lat'];

$lng=$result['results'][0]['geometry']['location']['lng'];

$range = 50;  

       // Find Max - Min Lat / Long for Radius and zero point and query  
       $lat_range = $range/69.172;  
       $lon_range = abs($range/(cos($latitude) * 69.172));  
       $min_lat = number_format($lat - $lat_range, "4", ".", "");  
       $max_lat = number_format($lat + $lat_range, "4", ".", "");  
       $min_lon = number_format($lng - $lon_range, "4", ".", "");  
       $max_lon = number_format($lng + $lon_range, "4", ".", "");

Then I set up the sql query as follows...

$LA1_RESULTS = "-1";
if (isset($min_lat)) {
$LA1_RESULTS = $min_lat;
}
$LO1_RESULTS = "-1";
if (isset($min_long)) {
$LO1_RESULTS = $min_long; 
}
$LO2_RESULTS = "-1";
if (isset($max_long)) {
$LO2_RESULTS = $max_long;
}
$LA2_RESULTS = "-1";
if (isset($max_lat)) {
$LA2_RESULTS = $max_lat;
}
mysql_select_db($database_XMASTREE, $XMASTREE);
$query_RESULTS = sprintf("SELECT * FROM zip_code WHERE zip_code.latitude BETWEEN %s AND      %s AND zip_code.longitude BETWEEN %s AND %s", GetSQLValueString($LA1_RESULTS, "int"),GetSQLValueString($LA2_RESULTS, "int"),GetSQLValueString($LO1_RESULTS, "int"),GetSQLValueString($LO2_RESULTS, "int"));
$RESULTS = mysql_query($query_RESULTS, $XMASTREE) or die(mysql_error());
$row_RESULTS = mysql_fetch_assoc($RESULTS);
$totalRows_RESULTS = mysql_num_rows($RESULTS);

The output can be seen at http://signature-online.net/xmastrees/zipsearch.php where it gives the lat and long variables correctly. I have set up the lat and long in the database as decimal (6 decimal places).

I am the original "know just enough to be dangerous"! Can anyone figure out what I have done wrong?

score 1 · Answer 1 · edited May 23 '17 at 12:03

1

Do you realize this method will return points in a square with sides of 50, not a circle with radius 50?

The basic math is covered in Equation for testing if a point is inside a circle.

So instead of figuring out your max/min for your geo points, you can let the server most of the work:

SELECT * 
FROM zip_code 
WHERE 
    (
        POWER(latitude - "INPUT LATITUDE", 2) 
        + 
        POWER(longitude - "INPUT LONGITUDE", 2) 
    ) 
    < POWER("RADIUS",2)

edited May 23 '17 at 12:03

Community

1
1

answered Feb 07 '14 at 04:17

K.A.F.

2,277
1
16
17

Thank you to all of you who responded. It was way over my head to get this working as sophisticated as your solution looks, it kept telling me there was a coding error. So because this is a very small databse (only 30 records) I actually looked up the zip codes within the radius and added them as a list in a separate field. Then I was able to create the search paramaters within my limited knowledge. I really appreciate the answers you guys gave! My non-techie workaround will probably have you chuckling! – Bill Teale Feb 08 '14 at 02:17
well I added the query using DW CS6 and it tells me there is a coding error in $query_ZIPLOCATE = "SELECT * FROM MEMBERS WHERE ( POWER(latitude - "INPUT LATITUDE", 2) + POWER(longitude - "INPUT LONGITUDE", 2) ) < POWER("RADIUS",2)"; – Bill Teale Feb 09 '14 at 13:36
The parts in double quotes are meant to be replaced your variable numbers, by the lat and long of your center point (ie `$lat` and `$lng`) and the radius of your search (ie `$range/69.172`) – K.A.F. Feb 10 '14 at 22:45

score 0 · Answer 2 · answered Feb 07 '14 at 01:36

0

Try setting decimal to 8 places.

answered Feb 07 '14 at 01:36

Sirago

101
3

php lat long radius search from zip code

2 Answers2