Форумы GIS-Lab.info

Код: Выделить всё

define('tile_size', 256);

function google_name2tile($name)
{
	$tile_x = 0; 
	$tile_y = 0;

	$pattern = array('q'=>array(0,0), 'r'=>array(1,0), 't'=>array(0,1), 's'=>array(1,1));

	$level = strlen($code);

	for($i=1; $i<=$level; $i++)
	{
		$key = $name{$i};

		$tile_x = $tile_x * 2 + $pattern[$key][0];
		$tile_y = $tile_y * 2 + $pattern[$key][1];
	}

	return array($tile_x, $tile_y, $level);
}

function google_tile2bitmap($tile_x, $tile_y)
{
	$x = $tile_x * tile_size;
	$y = $tile_y * tile_size;

	return array($x, $y);
}

function google_bitmap2merkator($x, $y, $level)
{
	$merkator_reference = 6371000;
	$merkator_size = 2 * M_PI * $merkator_reference;

	$num_tiles = pow(2, $level);
	$bitmap_size = $num_tiles * tile_size;
	$bitmap_center = $bitmap_size / 2;

	$pixels_per_merkator_rad = $merkator_size / $bitmap_size;

	$merkator_x = $pixels_per_merkator_rad * ($x - $bitmap_center);
	$merkator_y = $pixels_per_merkator_rad * ($bitmap_center - $y);

	return array($merkator_x, $merkator_y);
}