Hi everyone, I have been asked to write a script that will find towns within a radius of 10 miles (for instance) in a database. I have a database of towns with their corresponding latitude and longitude and I am fine working with the database, SQl etc but I have no idea how to work the coordinates. Does any one know how to calcuate distances using coordinates?

Hi, I wrote a method in a php class a few years back for calculating the distance between UK postcodes which worked by calculating the distance between grid reference points (northings and eastings), which I had stored in a database. With a bit of tweaking you could use this function to do what you need. However, you'll have to find someway of converting lat/long co-ordinates to grid references, you're on your own here so I advise you search google code as it may be done already. It's funny, this brings me back to my school days when we were doing trigonometry in Maths, and I said to my teacher: "Why would I want to know where a tree is going to fall when its cut, I've no interest in becoming a lumberjack!". So low and behold I got my first lesson in Latin maths, enter Pythagoras with his 'theorem' and the famous 'hypotenuse'! Anyway, sorry for going off in a tangent, it just instantly made me think of that day in school! PHP: function calcDistance($easting1,$northing1,$easting2,$northing2){ // Calculate the northing and easting distance $northingDistance=$northing1-$northing2; $eastingDistance=$easting1-$easting2; // Calculate the distance between the two points (Pythagoras' Theorem) $hypotenuse=sqrt(($northingDistance*$northingDistance)+($eastingDistance*$eastingDistance)); $kms = round($hypotenuse/1000,2); $miles = $kms * .62; return $miles;}

Hi oliflorence, I'm working on some regional analysis and need to create a database of irish towns and their latitude and longitude. Would you mind sharing the database you have? many thanks,

Hi There, I am afraid the project did not materialise for me so at the end i did not build the database, thus I might need similar shortly. Sorry i can't assist further.