道格拉斯坐标抽稀算法 无 $polyline = "116.621222,41.028553;116.621648,41.029848;.....";$pl = split(";", $polyline);$plstr = "";$flag = 0;$min = 0.0001;for ($j=0; $j count($pl)-1; $j=$j+3) { $xy1 = split(",", $pl[$j]);$x1 = $xy1[0];$y1 = $xy1
道格拉斯坐标抽稀算法
$polyline = "116.621222,41.028553;116.621648,41.029848;.....";
$pl = split(";", $polyline);
$plstr = "";
$flag = 0;
$min = 0.0001;
for ($j=0; $j < count($pl)-1; $j=$j+3) {
$xy1 = split(",", $pl[$j]);
$x1 = $xy1[0];
$y1 = $xy1[1];
$xy2 = split(",", $pl[$j+2]);
$x2 = $xy2[0];
$y2 = $xy2[1];
$b = $x1 - $x2;
$a = $y2 - $y1;
$c = ($y1 - $y2)*$x1 - $y1*($x1 -$x2);
$xys = split(",", $pl[$j+1]);
$d = (abs($a * $xys[0] + $b * $xys[1] + $c)) / (sqrt($a * $a + $b * $b));
if($d < $min) {
if($flag == 0)
$plstr .= $pl[$j+1];
else
$plstr .= ";".$pl[$j+1];
$flag++;
}
}
$polyline = $plstr;
//希望有技术大神多多提点，帮助我完善代码，万分感谢
