Question

我们有一台设备输出其GPS坐标作为数值，以ISO 6709 lat / lon格式输入Lat =±DDMM.MMMM＆amp; Lon =±DDDMM.MMMM

R中是否有包含函数（或自定义函数）的软件包将其转换为十进制度格式？（即：±DD.DDDDDD＆amp;±DDD.DDDDDD）

一个例子是lat＆amp; lon（2433.056，-8148.443）将被转换为（24.55094，-81.80739）。

Answer 1

您可以使用read.csv或read.delim等内容读取文件中的值。

然后从DDMM.MMMM和DDDMM.MMMM转换你可以使用这样的东西（当然根据输入/输出的形式修改）：

convertISO6709 <- function( lat, lon ) {
    # will just do lat and lon together, as the process is the same for both
    # It's simpler to do the arithmetic on positive numbers, we'll add the signs
    #  back in at the end.
    latlon <- c(lat,lon)
    sgns   <- sign(latlon)
    latlon <- abs(latlon)

    # grab the MM.MMMM bit, which is always <100. '%%' is modular arithmetic.
    mm <- latlon %% 100

    # grab the DD bit. Divide by 100 because of the MM.MMMM bit.
    dd <- (latlon - mm)/100

    # convert to decimal degrees, don't forget to add the signs back!
    out_latlon <- (dd+mm/60) * sgns
    return(out_latlon)
}

Answer 2

这可能不是最优雅的PHP代码，但确实有效：

function convertISO6709($coord)
{
    $abs_coord = abs($coord);
    $sign = ($abs_coord == $coord) ? 1 : -1;
    $m = 2;
    $dlen = 2;
    $s = 0;
    $seconds = 0;
    switch (strlen($abs_coord)) {
        case 4 :
            break;
        case 5 :
            $dlen = 3;
            $m = 3;
            break;
        case 6 :
            $s = 4;
            break;
    }
    $degrees = substr($abs_coord, 0, $dlen);
    $minutes = substr($abs_coord, $m, 2);
    if ($s != 0) {
        $seconds = substr($abs_coord, $s, 2);
    }
    return ($degrees + ($minutes / 60)  + ($seconds / 3600)) * $sign;
}

Answer 3

我有一个类似的问题从FedEx WS获取坐标。我使用此函数从+ 19.467945-99.14357 /：

这样的字符串中获取值

function convertCoordISO6709($coord)
{
  //$coord example
  //$coord = +19.467945-99.14357/

  $returnArray[0] = 1;//result non 0 means error
  $returnArray[1] = 0;//Lat
  $returnArray[2] = 0;//long

  $coord = trim($coord,"/"); //Strip / sign
  //look for + - sign
  $lat_sign = substr($coord,0,1);  //strip and save the first sign (latitude value)

  $sub_coord = substr($coord,1,strlen($coord));

  if(count(explode("+",$sub_coord)) == 2) //Second value is + for the longitude
  {
    $coords=explode("+",$sub_coord);
    $returnArray[0] = 0;
    $returnArray[1] =  $lat_sign.$coords[0];
    $returnArray[2] =  "+".$coords[1];    
  }
  else //Second value is - for the longitude
  {
    $coords=explode("-",$sub_coord);
    $returnArray[0] = 0;    
    $returnArray[1] =  $lat_sign.$coords[0];
    $returnArray[2] =  "-".$coords[1];      
  }


  return $returnArray;
}

将ISO 6709格式化GPS坐标转换为R中的十进制度

3 个答案: