<?php
	//根据经纬度计算两地距离
	function getDistance($lat1, $lng1, $lat2, $lng2){
		$r = 6378.137;	//地球半径
		
		//角度转为弧度
		$radLat1 = deg2rad($lat1);
		$radLat2 = deg2rad($lat2);
		$radLng1 = deg2rad($lng1);
		$radLng2 = deg2rad($lng2);		

		//sqrt：平方根，pow(x, n)：x的n次方的幂，asin：反正弦，sin：正弦
		$s = 2*asin(sqrt(pow(sin(($radLat1 - $radLat2)/2),2)+cos($radLat1)*cos($radLat2)*pow(sin(($radLng1-$radLng2)/2),2)))*$r;
		return $s;
	}
	
	//根据经纬度查地址
	function get_location($location_x,$location_y){
			$url = "http://api.map.baidu.com/geocoder/v2/?ak=GHvfRpIKsKLAgGNacrFdG8Uy&location=$location_x,$location_y&output=json&pois=0";
			$curl = curl_init();
			curl_setopt($curl, CURLOPT_URL, $url);
			curl_setopt($curl, CURLOPT_HEADER, 0);
			curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
			$data = curl_exec($curl);
			curl_close($curl);
			$res = json_decode($data,true);
			return $res;
	}
	
	//根据地址查经纬度
	function get_loca($address){
			$url = "http://api.map.baidu.com/geocoder/v2/?address=$address&output=json&ak=GHvfRpIKsKLAgGNacrFdG8Uy";
			$curl = curl_init();
			curl_setopt($curl, CURLOPT_URL, $url);
			curl_setopt($curl, CURLOPT_HEADER, 0);
			curl_setopt($curl, CURLOPT_RETURNTRANSFER, 1);
			$data = curl_exec($curl);
			curl_close($curl);
			$res = json_decode($data,true);
			return $res;
	}