抓取Mapbar地图切片的一个算法

发表于 2011/03/26

这个算法去年的时候就写了，自己就是抓着玩，也算是验证了这个算法的可行性，今天特向大家分享一下，主要是根据Mapbarapi里的绘图算法写出来的，实在没什么技术含量。

有想玩的同学可以试试，不过因此引起的后果本人概不负责，请慎重啊！

算法使用PHP写的，将下面代码保存为一个PHP文件后在终端运行: $ php -f filename.php一下就可以了。

代码如下：

/** * 抓取mapbar切片的算法 by CrossYou at 2011/01/22 *  * @version 1.0.0 * @linkhttp://crossyou.cn/ */$mapbarImgRoot = './mapbar/';//每层地图切片的文件夹名称$levelFolder = array('W','0','1','2','3','4','5','6','7','8','9','10','11','12','13','16');//每层地图切片所跨的经度数$cutImgLonRange=array(90,40,20,10,5,2,1,0.5,0.2,0.1,0.05,0.02,0.01,0.005,0.002,0.001);//每层地图切片所跨的维度数$cutImgLatRange=array(90*0.8,40*0.8,20*0.8,10*0.8,5*0.8,2*0.8,0.8,0.5*0.8,0.2*0.8,0.1*0.8,0.05*0.8,0.02*0.8,0.01*0.8,0.005*0.8,0.002*0.8,0.001*0.8);$blockSize=array(10,10,10,10,10,10,10,10,10,10,50,50,50,50,50,50);for($zoomLevel=0;$zoomLevel<16;$zoomLevel++){$clipXNum=ceil(360/$cutImgLonRange[$zoomLevel]);$clipYNum=ceil(90/$cutImgLatRange[$zoomLevel]);$clipLonRange = $cutImgLonRange[$zoomLevel];$clipLatRange = $cutImgLatRange[$zoomLevel];$clipXGap = -180-$clipLonRange/2;//从缩放级别5开始，只抓取中国范围内的地图，因为此级别以后的，非国内的都是背景图，抓了无意义。if($zoomLevel>3){//--------中国范围的地图$west = 73;$east = 136;$north = 54;$south = 3;$chinaLonRange = 63;//中国经度跨度$chinaLatRange = 51;//中国维度跨度$chinaClipXNum = ceil($chinaLonRange/$clipLonRange);$chinaClipYNum = ceil($chinaLatRange/$clipLatRange);for($i=0;$i<$chinaClipXNum;$i++){$lon = $west+$clipLonRange*$i;for($j=0;$j<$chinaClipYNum;$j++){$lat = $south+$clipLatRange*$j;$clipXNo =  floor($lon/$cutImgLonRange[$zoomLevel]);$clipYNo =  floor($lat/$cutImgLatRange[$zoomLevel]);$clipXNo=($clipXNo)%$clipXNum;if($clipXNo>=$clipXNum/2)$clipXNo-=$clipXNum;if($clipXNo<-$clipXNum/2)$clipXNo+=$clipXNum;echo "\n新的切片... => \n";echo '经纬度：'.$lon.' , '.$lat."\n";echo "-------------------------------\n";echo '切片序号：'.$clipXNo.' , '.$clipYNo."\n";echo "-------------------------------\n";//切片分文件夹存放位置$folderXNo = (int)floor($clipXNo/$blockSize[$zoomLevel]);//切片分文件夹存放位置$folderYNo = (int)floor($clipYNo/$blockSize[$zoomLevel]);if($folderXNo<0){$folderXNo+=1;}if($folderYNo<0){$folderYNo+=1;}$fileXNo =($clipXNo)-$folderXNo*$blockSize[$zoomLevel];$fileYNo =($clipYNo)-$folderYNo*$blockSize[$zoomLevel]; $imgPre = 'http://img.mapbar.com/maplite/mapbank/mapbar/';$imgDir = $levelFolder[$zoomLevel].'/'.$folderXNo.'_'.$folderYNo.'/';$imgName = $fileXNo.'_'.$fileYNo.'.png';$imgUrl = $imgPre.$imgDir.$imgName;$localImgDir = $mapbarImgRoot.$imgDir;$localImgName = $localImgDir.$imgName;if (!is_file($localImgName)){createdir($localImgDir);if(copy($imgUrl,$localImgName)){echo '图片:=> '.$imgDir.$imgName." 成功下载到本地\n\n";}}}}}else{for($i= -$clipXNum/2;$i<=$clipXNum/2;$i++){$lon = $clipLonRange*$i;if($i<0)$lon+=$clipLonRange/2;if($i==0)continue;if($i>0)$lon-=$clipLonRange/2;for($j=-$clipYNum;$j<=$clipYNum;$j++){$lat = $clipLatRange*$j;if($j<0)$lat+=$clipLatRange/2;if($j==0)continue;if($j>0)$lat-=$clipLatRange/2;$clipXNo =  floor($lon/$cutImgLonRange[$zoomLevel]);$clipYNo =  floor($lat/$cutImgLatRange[$zoomLevel]);$clipXNo=($clipXNo)%$clipXNum;if($clipXNo>=$clipXNum/2)$clipXNo-=$clipXNum;if($clipXNo<-$clipXNum/2)$clipXNo+=$clipXNum;echo "\n新的切片... => \n";echo '经纬度：'.$lon.' , '.$lat."\n";echo "-------------------------------\n";echo '切片序号：'.$clipXNo.' , '.$clipYNo."\n";echo "-------------------------------\n";//切片分文件夹存放位置$folderXNo = (int)floor($clipXNo/$blockSize[$zoomLevel]);//切片分文件夹存放位置$folderYNo = (int)floor($clipYNo/$blockSize[$zoomLevel]);if($folderXNo<0){$folderXNo+=1;}if($folderYNo<0){$folderYNo+=1;}$fileXNo =($clipXNo)-$folderXNo*$blockSize[$zoomLevel];$fileYNo =($clipYNo)-$folderYNo*$blockSize[$zoomLevel]; $imgPre = 'http://img.mapbar.com/maplite/mapbank/mapbar/';$imgDir = $levelFolder[$zoomLevel].'/'.$folderXNo.'_'.$folderYNo.'/';$imgName = $fileXNo.'_'.$fileYNo.'.png';$imgUrl = $imgPre.$imgDir.$imgName;$localImgDir = $mapbarImgRoot.$imgDir;$localImgName = $localImgDir.$imgName;if (!is_file($localImgName)){createdir($localImgDir);if(copy($imgUrl,$localImgName)){echo '图片:=> '.$imgDir.$imgName." 成功下载到本地\n\n";}}}}}}/** * 创建多级目录 摘自网络 * 如有好的建议，请到 http://crossyou.cn/给我留言 谢谢！ *  * @since 1.0.5 * @param string $dir */function createdir($dir){$array_dir=explode("/",$dir);//把多级目录分别放到数组中$depth = count($array_dir);$path = '';for($i=0;$i<$depth;$i++){$path .= $array_dir[$i]."/";if(!is_dir($path)){mkdir($path);}}}

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