Mapbar地图切片的抓取和拼接算法

来源：互联网发布：购物车图片淘宝搞笑编辑：程序博客网时间：2024/05/31 13:14

转自：http://blog.csdn.net/mygisforum/article/details/7022860

1.MapBar 地图瓦片抓取算法

此地图瓦片抓取算法是根据Mapbarapi里的绘图算法写出来的，使用PHP编写，将代码保存为一个PHP文件后，然后使用命令行运行: $ php -f filename.php。

注：cmd>cd "x:\...\php.exe"。

[php] view plaincopy
<?php  
/** 
 * 抓取mapbar切片的算法 by CrossYou at 2011/01/22 
 * 
 * @version 1.0.0 
 * @link    http://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);  
        }  
    }  
}  
?>  

2.MapBar地图瓦片拼接算法

作者制作的一个Demo：http://www.crossyou.cn/attachments/2011/03/mapbar.html。下面的源代码可能用到了一小点的jQuery。

[javascript] view plaincopy
var divId = 'map';  
var imgWidth        = 300;  
var imgHeight       = 300;  
var imgExt          = 'png';  
var centerpoint     = '120.15689,35.96333';  
var point           = centerpoint.split(',');  
var _centerLon      = point[0];  
var _centerLat      = point[1];  
var zoomlevel       = 8;  
var $map            = $('#'+divId);  
  
//每层地图切片的文件夹名称  
var levelFolder     = new 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  
var cutImgLonRange  = new 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  
var cutImgLatRange  = new 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);  
//地图区块大小 将不同区块的放在不同的文件夹下面进行管理  
var blockSize       = new Array(10,10,10,10,10,10,10,10,10,10,50,50,50,50,50,50);  
  
//纬度的偏移  
var latOffset       = new Array(0,0,0,0,0,0,0,0,75,0,0,-150,0,0,0,0);  
  
function drawMap(){  
    var LatLon          = coordOffsetDecrypt(_centerLon,_centerLat);//解密Mapbar坐标  
    centerLon           = LatLon[0];  
    centerLat           = LatLon[1];  
  
    var mapwidth        = $map.width();  
    var mapheight       = $map.height();  
  
    var halfNum5clipX   = Math.ceil(mapwidth/imgWidth/2);  
    var halfNum5clipY   = Math.ceil(mapheight/imgHeight/2);  
  
    var _blockSize      = blockSize[zoomlevel];  
    var clipLonRange    = cutImgLonRange[zoomlevel];  
    var clipLatRange    = cutImgLatRange[zoomlevel];  
    var multiple        = 100000;  
  
    var clipXNum=(360/clipLonRange);  
    rotationCosVal=1.0;  
    rotationSinVal=0.0;  
  
    var Clip = [];  
    clipNo5X=Math.floor((centerLon)/clipLonRange);  
    clipNo5Y=Math.floor((centerLat)/clipLatRange);  
    if(clipNo5X<0)clipNo5X+=1;  
  
    var mapX=mapwidth/2-Math.round(((centerLon*multiple)%(clipLonRange*multiple))*imgWidth/(clipLonRange*multiple));  
    if(centerLat>=0) {  
        mapY=mapheight/2-imgHeight+Math.round(((centerLat*multiple)%(clipLatRange*multiple))*imgHeight/(clipLatRange*multiple));  
    }else {  
        mapY=mapheight/2+Math.round(((centerLat*multiple)%(clipLatRange*multiple))*imgHeight/(clipLatRange*multiple));  
    }  
    $map.html('');  
    // -- 真正给力的开始  
    for (var _clipXNo = -halfNum5clipX - 1; _clipXNo <= halfNum5clipX; _clipXNo++) {  
        for (var _clipYNo = -halfNum5clipY - 1; _clipYNo <= halfNum5clipY; _clipYNo++) {  
            try {  
                var clipXNo = parseInt(clipNo5X + _clipXNo);//地图横向切片序列号  
                var clipYNo = parseInt(clipNo5Y + _clipYNo);  
                clipXNo = (clipXNo) % clipXNum  
                if (clipXNo >= (clipXNum / 2))  
                    clipXNo -= clipXNum;  
                if (clipXNo < (-clipXNum / 2))  
                    clipXNo += clipXNum;  
                var folderX = parseInt(Math.floor((clipXNo) / _blockSize));  
                var folderY = parseInt(Math.floor((clipYNo) / _blockSize));  
  
                if (folderX < 0)  
                    folderX += 1;  
                if (folderY < 0)  
                    folderY += 1;  
  
                var fileXNo = (clipXNo) - folderX * _blockSize;  
                var fileYNo = (clipYNo) - folderY * _blockSize;  
  
                var _strImgUrl = 'http://img.mapbar.com/maplite/mapbank/mapbar/' + levelFolder[zoomlevel] + '/';  
                if (zoomlevel >= 14)  
                    _strImgUrl += folderX + "/";  
  
                _strImgUrl += folderX + "_" + folderY + "/";  
                _strImgUrl += fileXNo + "_" + fileYNo + "." + imgExt;  
  
                var clipLeft = (_clipXNo * imgWidth) + parseInt(mapX);  
                var clipTop = (-(_clipYNo * imgHeight) + parseInt(mapY));  
  
                clipTop = clipTop + latOffset[zoomlevel];  
  
                var isClearImgUrl = false;  
  
                if ((clipLeft < -imgWidth || clipLeft > mapwidth || clipTop > mapheight || clipTop < -imgHeight))  
                    isClearImgUrl = true;  
  
                if (isClearImgUrl)  
                    continue;  
  
                var clipId = ((zoomlevel).toString(16) + (clipNo5X + _clipXNo).toString(16) + 'l' + (clipNo5Y + _clipYNo).toString(16)).toLowerCase();  
  
                if (_strImgUrl && _strImgUrl.indexOf("NaN") < 0) {  
                    if (Clip[clipId] == null) {  
                        Clip[clipId] = new Image();  
                        Clip[clipId].id = clipId;  
                        Clip[clipId].name = clipId;  
                        Clip[clipId].unselectable = "on";  
                        Clip[clipId].style.position = "absolute";  
                        Clip[clipId].style.MozUserSelect = "none";  
                        Clip[clipId].src = _strImgUrl;  
  
                    }  
  
                    var p2 = (clipLeft + imgWidth / 2 - mapwidth / 2) * rotationCosVal - (clipTop + imgHeight / 2 - mapheight / 2) * rotationSinVal + mapwidth / 2;  
                    var p5 = (clipLeft + imgWidth / 2 - mapwidth / 2) * rotationSinVal + (clipTop + imgHeight / 2 - mapheight / 2) * rotationCosVal + mapheight / 2;  
  
                    Clip[clipId].style.top = parseInt(p5 - imgHeight / 2) + "px";  
                    Clip[clipId].style.left = parseInt(p2 - imgWidth / 2) + "px";  
                    //var interval = parseInt($('#interval').val());  
  
                    $map.append(Clip[clipId]);  
                }  
                _strImgUrl = null;  
            }  
            catch (e) {  
                throw (e);  
            }  
        }  
    }  
}  
  
// The follow is two helper functions  
  
/** 
 * 将真实地理坐标加密为Mapbar经纬度坐标 
 * 
 * @param x 经度值 
 * @param y 维度值 
 * @returns [x,y] 
 */  
function coordOffsetEncrypt(x,y){  
    x = parseFloat(x)*100000%36000000;  
    y = parseFloat(y)*100000%36000000;  
  
    _X = parseInt(((Math.cos(y/100000))*(x/18000))+((Math.sin(x/100000))*(y/9000))+x);  
    _Y = parseInt(((Math.sin(y/100000))*(x/18000))+((Math.cos(x/100000))*(y/9000))+y);  
  
    return [_X/100000.0,_Y/100000.0];  
}  
  
/** 
 * 将Mapbar经纬坐标解密为真实地理坐标 
 * 
 * @param x 经度值 
 * @param y 维度值 
 * @returns [x,y] 
 */  
function coordOffsetDecrypt(x,y){  
    x = parseFloat(x)*100000%36000000;  
    y = parseFloat(y)*100000%36000000;  
  
    x1 = parseInt(-(((Math.cos(y/100000))*(x/18000))+((Math.sin(x/100000))*(y/9000)))+x);  
    y1 = parseInt(-(((Math.sin(y/100000))*(x/18000))+((Math.cos(x/100000))*(y/9000)))+y);  
  
    x2 = parseInt(-(((Math.cos(y1/100000))*(x1/18000))+((Math.sin(x1/100000))*(y1/9000)))+x+((x>0)?1:-1));  
    y2 = parseInt(-(((Math.sin(y1/100000))*(x1/18000))+((Math.cos(x1/100000))*(y1/9000)))+y+((y>0)?1:-1));  
  
    return [x2/100000.0,y2/100000.0];  
}  

原文出自 CrossYou'Blog ：

抓取算法：http://www.crossyou.cn/an-algorithm-to-crawl-mapbar-map.htm

瓦片拼接算法：http://www.crossyou.cn/a-simple-map-of-the-source-code-mapbar.htm

注：以上内容仅供学习，在此严重感谢作者分享。

后记：经验证，百度使用的MapBar的地图，算法相同，其url前缀为：

http://img.mapbar.com/maplite/mapbank/baidu/