Distance calculation based on multiple locations (Lat,Lon) including starting/ finishing point - php

Question

I would like to calculate the total distance of driving beetween multiple locations (loop), including the distance (starting point (garage) - first location sarting point) and (last location finishig point - finishing point (garage)).
Example:
(Garage + D1) + (D1 + D2) + (D2 + E1) + (E1 + E2) + E2 + Garage)
I'm having a problem with the correct looping. Here's my simplified code:
<?
$driver = 5;
$result2 = mysql_query("SELECT * FROM test WHERE id='$driver' LIMIT 1") or die(mysql_error());
while($row2 = mysql_fetch_array( $result2 )) {
$lon=$row2['lon'];
$lat=$row2['lat'];
echo "$lon, $lat";
}
$result = mysql_query("SELECT * FROM test1 WHERE driver='$driver'") or die(mysql_error());
while($row = mysql_fetch_array( $result )) {
$lon1=$row['lon1'];
$lat1=$row['lat1'];
$lon2=$row['lon2'];
$lat2=$row['lat2'];
////////// distance between driver address and starting address
$distancecalc = (3958*3.1415926*sqrt(($lat-$lat1)*($lat-$lat1) + cos($lat/57.29578)*cos($lat1/57.29578)*($lon-$lon1)*($lon-$lon1))/180);
////////// distance between statring address and finishing address - multiple adsresses
$distancecalc1 = $distancecalc1 + (3958*3.1415926*sqrt(($lat2-$lat1)*($lat2-$lat1) + cos($lat2/57.29578)*cos($lat1/57.29578)*($lon2-$lon1)*($lon2-$lon1))/180);
////////// distance between finishing address and driver address
$distancecalc2 = (3958*3.1415926*sqrt(($lat2-$lat)*($lat2-$lat) + cos($lat2/57.29578)*cos($lat/57.29578)*($lon2-$lon)*($lon2-$lon))/180);
$distancetotal = $distancecalc + $distancecalc1 +$distancecalc2;
echo "$distancecalc<br>
$distancecalc1<br>
$distancecalc2<br>";
}
echo "$distancetotal";
?>
I tried some things (mostly if... ) and also with more database requests, but I'm still having the problem of avoiding multiple calculations, and I also strongly believe there is way to code it to make it easier and clearer.
I would appreciate some help on this one.
Thank you very much.

Answer 1

Here's the function you need:
function distance ($lat1, $lon1, $lat2, $lon2) {
return (3958*3.1415926*sqrt(($lat2-$lat1)*($lat2-$lat1) + cos($lat2/57.29578)*cos($lat1/57.29578)*($lon2-$lon1)*($lon2-$lon1))/180);
}
The function body is exactly the same as the formula you used in-line, so I don't understand why you needed help with this.

Answer 2

The number 6367 - is the radius of the Earth in kilometers
DELIMITER $$
DROP FUNCTION IF EXISTS geodist $$
CREATE FUNCTION geodist (
src_lat DECIMAL(9,6), src_lon DECIMAL(9,6),
dst_lat DECIMAL(9,6), dst_lon DECIMAL(9,6)
) RETURNS DECIMAL(6,2) DETERMINISTIC
BEGIN
SET #dist := 6367 * 2 * ASIN(SQRT(
POWER(SIN((src_lat - ABS(dst_lat)) * PI()/180 / 2), 2) +
COS(src_lat * PI()/180) *
COS(ABS(dst_lat) * PI()/180) *
POWER(SIN((src_lon - dst_lon) * PI()/180 / 2), 2)
));
RETURN #dist;
END $$
DELIMITER ;

Answer 3

Ok. I worked it out with help of mac_gyver (php freaks). All calculations are done as i wish. My code below:
<?
include "connectdb.php";
$driver = 5;
$datestamp = '2013/05/07';
$result2 = mysql_query("SELECT * FROM drivers WHERE id='$driver' LIMIT 1") or die(mysql_error());
while($row2 = mysql_fetch_array( $result2 )) {
$lon=$row2['lon'];
$lat=$row2['lat'];
}
$result = mysql_query("SELECT * FROM quotedb WHERE moveday='$datestamp' AND driver='$driver' AND cleared='Not Cleared' AND status='Done' ORDER BY moveday, timeday") or die(mysql_error());
$distance = 0; // accumulate the distance
$first_pass = true; // flag to detect the first row inside the loop
while($row = mysql_fetch_assoc( $result )) {
$lon2a=$lon2;
$lat2a=$lat2;
$lon1=$row['lon1'];
$lat1=$row['lat1'];
$lon2=$row['lon2'];
$lat2=$row['lat2'];
// calculate the distance from the Garage to the first point of the first row
if($first_pass){
$distance += (3958*3.1415926*sqrt(($lat-$lat1)*($lat-$lat1) + cos($lat/57.29578)*cos($lat1/57.29578)*($lon-$lon1)*($lon-$lon1))/180);
$first_pass = false;
}
// calculate the distance for each row (segment) in the route
$distance += (3958*3.1415926*sqrt(($lat2-$lat1)*($lat2-$lat1) + cos($lat2/57.29578)*cos($lat1/57.29578)*($lon2-$lon1)*($lon2-$lon1))/180);
if ( $lon2a == "" or $lat2a =="" ) {
} else {
// calculate the distance from the second point of the first row to the first point of the next row
$distance += (3958*3.1415926*sqrt(($lat2a-$lat1)*($lat2a-$lat1) + cos($lat2a/57.29578)*cos($lat1/57.29578)*($lon2a-$lon1)*($lon2a-$lon1))/180);
}
}
// calculate the distance from the second point of the last row to the Garage
$distance += (3958*3.1415926*sqrt(($lat2-$lat)*($lat2-$lat) + cos($lat2/57.29578)*cos($lat/57.29578)*($lon2-$lon)*($lon2-$lon))/180);
echo "$distance<br>
";
?>
Still think there is a place for improvement in the code. Will aplay Haversine method for calculations. Do you guys have some suggestion to improve this piece of code ... thx

Answer 4

Impoved version:
<?
include "connectdb.php";
$driver = 5;
$datestamp = '2013/05/07';
$result2 = mysql_query("SELECT * FROM drivers WHERE id='$driver' LIMIT 1") or die(mysql_error());
while($row2 = mysql_fetch_array( $result2 )) {
$garage_lon=$row2['lon'];
$garage_lat=$row2['lat'];
}
$result = mysql_query("SELECT * FROM quotedb WHERE moveday='$datestamp' AND driver='$driver' AND cleared='Not Cleared' AND status='Done' ORDER BY moveday, timeday") or die(mysql_error());
function calculate_distance($lon1, $lat1, $lon2, $lat2) {
return (3958 * 3.1415926 * sqrt(($lat2 - $lat1) * ($lat2 - $lat1) + cos($lat2 / 57.29578) * cos($lat1 / 57.29578) * ($lon2 - $lon1) * ($lon2 - $lon1)) / 180);}
$previous_lon = $garage_lon;
$previous_lat = $garage_lat;
$distance = 0; // accumulate the distance
while($row = mysql_fetch_assoc( $result ))
{
$lon1 = $row['lon1'];
$lat1 = $row['lat1'];
$lon2 = $row['lon2'];
$lat2 = $row['lat2'];
if ( $previous_lon && $previous_lat )
{
// calculate the distance from the second point of the first row to the first point of the next row
$distance += calculate_distance($lon1, $lat1, $previous_lon, $previous_lat);
}
// calculate the distance for each row (segment) in the route
$distance += calculate_distance($lon1, $lat1, $lon2, $lat2);
$previous_lon = $lon2;
$previous_lat = $lat2;
}
// calculate the distance from the second point of the last row to the Garage
$distance += calculate_distance($garage_lon, $garage_lat, $lon2, $lat2);
$distance = round($distance,0);
echo "$distance<br>
";
?>