如果这对你有用的话，你可以试试。

<?php

function DMStoDD($deg,$min,$sec)
{

    // Converting DMS ( Degrees / minutes / seconds ) to decimal format
    return $deg+((($min*60)+($sec))/3600);
}    

function DDtoDMS($dec)
{
    // Converts decimal format to DMS ( Degrees / minutes / seconds ) 
    $vars = explode(".",$dec);
    $deg = $vars[0];
    $tempma = "0.".$vars[1];

    $tempma = $tempma * 3600;
    $min = floor($tempma / 60);
    $sec = $tempma - ($min*60);

    return array("deg"=>$deg,"min"=>$min,"sec"=>$sec);
}    

?>

这里有一个例子，你可以在DMS值中输入纬度和经度，然后返回转换后的DMS字符串。

function DECtoDMS($latitude, $longitude)
{
    $latitudeDirection = $latitude < 0 ? 'S': 'N';
    $longitudeDirection = $longitude < 0 ? 'W': 'E';

    $latitudeNotation = $latitude < 0 ? '-': '';
    $longitudeNotation = $longitude < 0 ? '-': '';

    $latitudeInDegrees = floor(abs($latitude));
    $longitudeInDegrees = floor(abs($longitude));

    $latitudeDecimal = abs($latitude)-$latitudeInDegrees;
    $longitudeDecimal = abs($longitude)-$longitudeInDegrees;

    $_precision = 3;
    $latitudeMinutes = round($latitudeDecimal*60,$_precision);
    $longitudeMinutes = round($longitudeDecimal*60,$_precision);

    return sprintf('%s%s° %s %s %s%s° %s %s',
        $latitudeNotation,
        $latitudeInDegrees,
        $latitudeMinutes,
        $latitudeDirection,
        $longitudeNotation,
        $longitudeInDegrees,
        $longitudeMinutes,
        $longitudeDirection
    );

}

我编写了一个PHP函数，它可以完成下面的问题：将以度/分/秒为单位的字符串转换为十进制度。它接受多种不同格式的字符串，并遵循方向（NSEW）。
代码如下：

<?php
function convertDMSToDecimal($latlng) {
    $valid = false;
    $decimal_degrees = 0;
    $degrees = 0; $minutes = 0; $seconds = 0; $direction = 1;
    // Determine if there are extra periods in the input string
    $num_periods = substr_count($latlng, '.');
    if ($num_periods > 1) {
        $temp = preg_replace('/\./', ' ', $latlng, $num_periods - 1); // replace all but last period with delimiter
        $temp = trim(preg_replace('/[a-zA-Z]/','',$temp)); // when counting chunks we only want numbers
        $chunk_count = count(explode(" ",$temp));
        if ($chunk_count > 2) {
            $latlng = $temp; // remove last period
        } else {
            $latlng = str_replace("."," ",$latlng); // remove all periods, not enough chunks left by keeping last one
        }
    }

    // Remove unneeded characters
    $latlng = trim($latlng);
    $latlng = str_replace("º","",$latlng);
    $latlng = str_replace("'","",$latlng);
    $latlng = str_replace("\"","",$latlng);
    $latlng = substr($latlng,0,1) . str_replace('-', ' ', substr($latlng,1)); // remove all but first dash

    if ($latlng != "") {
        // DMS with the direction at the start of the string
        if (preg_match("/^([nsewNSEW]?)\s*(\d{1,3})\s+(\d{1,3})\s+(\d+\.?\d*)$/",$latlng,$matches)) {
            $valid = true;
            $degrees = intval($matches[2]);
            $minutes = intval($matches[3]);
            $seconds = floatval($matches[4]);
            if (strtoupper($matches[1]) == "S" || strtoupper($matches[1]) == "W")
                $direction = -1;
        }
        // DMS with the direction at the end of the string
        if (preg_match("/^(-?\d{1,3})\s+(\d{1,3})\s+(\d+(?:\.\d+)?)\s*([nsewNSEW]?)$/",$latlng,$matches)) {
            $valid = true;
            $degrees = intval($matches[1]);
            $minutes = intval($matches[2]);
            $seconds = floatval($matches[3]);
            if (strtoupper($matches[4]) == "S" || strtoupper($matches[4]) == "W" || $degrees < 0) {
                $direction = -1;
                $degrees = abs($degrees);
            }
        }
        if ($valid) {
            // A match was found, do the calculation
            $decimal_degrees = ($degrees + ($minutes / 60) + ($seconds / 3600)) * $direction;
        } else {
            // Decimal degrees with a direction at the start of the string
            if (preg_match("/^(-?\d+(?:\.\d+)?)\s*([nsewNSEW]?)$/",$latlng,$matches)) {
                $valid = true;
                if (strtoupper($matches[2]) == "S" || strtoupper($matches[2]) == "W" || $degrees < 0) {
                    $direction = -1;
                    $degrees = abs($degrees);
                }
                $decimal_degrees = $matches[1] * $direction;
            }
            // Decimal degrees with a direction at the end of the string
            if (preg_match("/^([nsewNSEW]?)\s*(\d+(?:\.\d+)?)$/",$latlng,$matches)) {
                $valid = true;
                if (strtoupper($matches[1]) == "S" || strtoupper($matches[1]) == "W")
                    $direction = -1;
                $decimal_degrees = $matches[2] * $direction;
            }
        }
    }
    if ($valid) {
        return $decimal_degrees;
    } else {
        return false;
    }
}
?>

下面是Github上的测试用例：https://github.com/prairiewest/PHPconvertDMSToDecimal

解决了。

<?php

 function DMStoDD($input)
{
    $deg = " " ;
    $min = " " ;
    $sec = " " ;  
    $inputM = " " ;        

    print "<br> Input is ".$input." <br>";

    for ($i=0; $i < strlen($input); $i++) 
    {                     
        $tempD = $input[$i];
         //print "<br> TempD [$i] is : $tempD"; 

        if ($tempD == iconv("UTF-8", "ISO-8859-1//TRANSLIT", '°') ) 
        { 
            $newI = $i + 1 ;
            //print "<br> newI is : $newI"; 
            $inputM =  substr($input, $newI, -1) ;
            break; 
        }//close if degree

        $deg .= $tempD ;                    
    }//close for degree

     //print "InputM is ".$inputM." <br>";

    for ($j=0; $j < strlen($inputM); $j++) 
    { 
        $tempM = $inputM[$j];
         //print "<br> TempM [$j] is : $tempM"; 

        if ($tempM == "'")  
         {                     
            $newI = $j + 1 ;
             //print "<br> newI is : $newI"; 
            $sec =  substr($inputM, $newI, -1) ;
            break; 
         }//close if minute
         $min .= $tempM ;                    
    }//close for min

        $result =  $deg+( (( $min*60)+($sec) ) /3600 );

        print "<br> Degree is ". $deg*1 ;
        print "<br> Minutes is ". $min ;
        print "<br> Seconds is ". $sec ;
        print "<br> Result is ". $result ;

return $deg + ($min / 60) + ($sec / 3600);

   }
?>

如果您还想包含引用，则可能需要使用以下函数：

function DMStoDD($ref, $deg, $min, $sec)
{
    $n = $deg + (($min * 60 + $sec) / 3600);
    if (($ref == "S") or ($ref == "W")) {
        return -$n;
    } else {
        return $n;
    }
}

这样做效果很好：

<?php echo "<td> $deg&#176 $min' $sec&#8243 </td>";  ?>

其中deg、min和sec是角坐标。