Python 之谷歌瓦片地图影像批量下载

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Python 之谷歌瓦片地图影像批量下载

2023-06-02 05:17| 来源: 网络整理| 查看: 265

最近在写毕业论文，想用谷歌影像作为底图来展示研究区，然后 Google 了很多脚本，结果发现输出的影像都不带空间坐标系，所以就想自己写个小工具，通过输入空间范围就可以实现 Google 地图的下载，并输出为 TIFF 格式，含 WGS 84 空间坐标系。

1、拟解决问题

下载谷歌影像，并输出为带空间坐标系的 TIFF 格式

2、简单说明

通过多线程、多进程的方式实现快速下载下面只给出主要的思路及代码文章末尾提供源码链接

3、主要思路及代码 3.1、计算给定空间范围内的瓦片行列号，并返回URL MAP_URLS = { "Google": "http://mts0.googleapis.com/vt?lyrs={style}&x={x}&y={y}&z={z}", "Google China": "http://mt2.google.cn/vt/lyrs={style}&hl=zh-CN&gl=CN&src=app&x={x}&y={y}&z={z}"} def get_url(source, x, y, z, style):# if source == 'Google China': url = MAP_URLS["Google China"].format(x=x, y=y, z=z, style=style) elif source == 'Google': url = MAP_URLS["Google"].format(x=x, y=y, z=z, style=style) else: raise Exception("Unknown Map Source ! ") return url def get_urls(x1, y1, x2, y2, z, source='google', style='s'): pos1x, pos1y = wgs_to_tile(x1, y1, z) pos2x, pos2y = wgs_to_tile(x2, y2, z) lenx = pos2x - pos1x + 1 leny = pos2y - pos1y + 1 print("Total tiles number：{x} X {y}".format(x=lenx, y=leny)) urls = [get_url(source, i, j, z, style) for j in range(pos1y, pos1y + leny) for i in range(pos1x, pos1x + lenx)] return urls 3.2、根据上一步得到的URL下载瓦片 def download_tiles(urls,multi=10): def makeupdate(s): def up(): global COUNT COUNT+=1 print("\rDownLoading...[{0}/{1}]".format(COUNT,s),end='') return up url_len=len(urls) datas=[None] * url_len if multi 20 or not isinstance(multi,int): raise Exception("multi of Downloader shuold be int and between 1 to 20.") tasks=[Downloader(i,multi,urls,datas,makeupdate(url_len)) for i in range(multi)] for i in tasks: i.start() for i in tasks: i.join() return datas 3.3、合并瓦片为一张影像 def merge_tiles(datas,x1, y1, x2, y2, z): pos1x, pos1y = wgs_to_tile(x1, y1, z) pos2x, pos2y = wgs_to_tile(x2, y2, z) lenx = pos2x - pos1x + 1 leny = pos2y - pos1y + 1 outpic = pil.new('RGBA', (lenx * 256, leny * 256)) for i, data in enumerate(datas): picio = io.BytesIO(data) small_pic = pil.open(picio) y, x = i // lenx, i % lenx outpic.paste(small_pic, (x * 256, y * 256)) print('\nTiles merge completed') return outpic 3.4、计算所下载瓦片的实际空间范围（我们需要的是瓦片边缘的经纬度信息） def getExtent(x1, y1, x2, y2, z,source="Google China"): pos1x, pos1y = wgs_to_tile(x1, y1, z) pos2x, pos2y = wgs_to_tile(x2, y2, z) Xframe=pixls_to_mercator({"LT":(pos1x,pos1y),"RT":(pos2x,pos1y),"LB":(pos1x,pos2y),"RB":(pos2x,pos2y),"z":z}) for i in ["LT","LB","RT","RB"]: Xframe[i]=mercator_to_wgs(*Xframe[i]) if source=="Google": pass elif source=="Google China": for i in ["LT","LB","RT","RB"]: Xframe[i]=gcj_to_wgs(*Xframe[i]) else: raise Exception("Invalid argument: source.") return Xframe 3.5、最后将结果输出为TIFF格式 def saveTiff(r,g,b,gt,filePath): fname_out = filePath driver = gdal.GetDriverByName('GTiff') # Create a 3-band dataset dset_output = driver.Create(fname_out, r.shape[1], r.shape[0], 3, gdal.GDT_UInt16) dset_output.SetGeoTransform(gt) try: proj = osr.SpatialReference() proj.ImportFromEPSG(4326) dset_output.SetSpatialRef(proj) except: print("Error: Coordinate system setting failed") dset_output.GetRasterBand(1).WriteArray(r) dset_output.GetRasterBand(2).WriteArray(g) dset_output.GetRasterBand(3).WriteArray(b) dset_output.FlushCache() dset_output = None print("Image Saved")

完成！您也可以点击这里获取完整的代码如果对您有用的话，别忘了给点个赞哦_ ！

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Python 之谷歌瓦片地图影像批量下载

Python 之谷歌瓦片地图影像批量下载

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