Aerial Photography High Resolution [ORTHO® HR — IGN-F] — Department of Calvados — 2020

The ORTHO® HR (High Resolution Orthophotography) of 2020 is a collection of digital mosaics of colour orthophotographs, rectified in the specific legal projection adapted to the covered territory. The ORTHO® HR 2020 is freely distributed under an open license thanks to the financial support of the European Union and the Normandy Region. It is requested that all studies carried out from this database include the particular mention produced with the support of Europe and the Normandy Region in the framework of the CRIGE Normandy”. The ORTHO® HR of 2020 offers many advantages: — spatial planning: land tenure, land use and new communication channels; — environment: coastal and forest observatory, bocage management; — communication: visualisation of the evolution of the territory. The original files distributed by the IGN on https://geoservices.ign.fr/documentation/diffusion/telechargement-donnees-libres.html#ortho-hr-sous-licence-ouverte under Open License are: — in legal projection (Lambert 93 in metropolis and other specific projection for each DOM) — JPEG2000 “lossless” format per slab of 1 km x 1 km — compressed as a 7z archive (long to decompress for marginal compression gain, slabs already compressed) Below you will find links to access “multi-party” files for free download on the IGN website. To unzip “multi-part” files: — Make sure you have downloaded all the parts: 001, 002, 003... — Put all parts in the same directory — Click on file 001 (e.g. ortho_2020.zip.001). No need to click 002, 003, 004... Open file.001 opens all other parts of the archive If you have an error there is a good chance that one of your files was only partially downloaded In order to make it easier to use the tiles making up the HR 2020 orthophoto, we also offer a pyramid in GeoPackage OGC format in lambert 93. **Collection context** **Collection method** The Geopakage was produced from the GDAL library: gdalbuildvrt D:\8_Ortho_2020\2020.vrt -addalpha -srcnodata 255 -hidenodata D:\8_Ortho_2020\data\*.jp2 gdalwarp D:\8_Ortho_2020\2020.vrt D:\8_Ortho_2020\2020.gpkg -t_srs EPSG:2154 -r cubic -of gpkg gdaladdo -r cubic D:\8_Ortho_2020\2020.gpkg 4 16 64 256 For more information, see [the metadata on the Isogeo catalog](https://open.isogeo.com/s/434296189d794266a04a8678e256f0c4/HiLeps3y1qrSx6aTDmKyp0spGPix0/r/5050e0e79ac1476f81df559edbd17306).2020年版ORTHO®高分辨率正射影像（High Resolution Orthophotography）数据集是一套经适配覆盖区域的法定投影校正的彩色正射影像数字镶嵌合集。 本2020年版ORTHO® HR数据集依托欧盟与诺曼底大区的财政支持，以开放许可协议免费分发。使用本数据库开展的所有研究，均需注明"本研究基于欧盟与诺曼底大区在诺曼底CRIGE框架下提供的支持完成"。 2020年版ORTHO® HR数据集具备诸多应用优势： — 空间规划领域：可用于土地权属、土地利用及新型交通通道相关研究； — 生态环境领域：可服务于海岸与森林监测、灌丛农田管理； — 可视化展示领域：可直观呈现区域发展变迁历程。 法国国家地理研究院（Institut Géographique National, IGN）在其官网https://geoservices.ign.fr/documentation/diffusion/telechargement-donnees-libres.html#ortho-hr-sous-licence-ouverte 以开放许可分发的原始文件具备以下特征： — 采用法定投影（法国本土采用Lambert 93投影，各海外省采用对应专属投影）； — 以JPEG2000“无损”格式存储，影像切块规格为1 km × 1 km； — 封装为7z压缩归档（虽压缩增益有限且切块本身已压缩，但解压耗时较长）。 您可通过IGN官网提供的链接免费下载“分卷”归档文件。 解压分卷归档文件的步骤如下： — 确认已下载所有分卷文件：001、002、003……； — 将所有分卷文件置于同一目录下； — 点击首个分卷文件（例如ortho_2020.zip.001），无需单独点击002、003、004……，打开.001文件即可自动加载归档的其余所有分卷。 若解压失败，大概率是某一分卷文件未完整下载。 为便于使用组成2020年版ORTHO® HR正射影像的影像切块，我们还提供采用Lambert 93投影的开放地理空间联盟（Open Geospatial Consortium, OGC）GeoPackage格式影像金字塔数据集。 **数据集背景** **数据集采集方法** 该GeoPackage数据集通过地理数据抽象库（Geospatial Data Abstraction Library, GDAL）生成，具体命令如下： gdalbuildvrt D:8_Ortho_20202020.vrt -addalpha -srcnodata 255 -hidenodata D:8_Ortho_2020data*.jp2 gdalwarp D:8_Ortho_20202020.vrt D:8_Ortho_20202020.gpkg -t_srs EPSG:2154 -r cubic -of gpkg gdaladdo -r cubic D:8_Ortho_20202020.gpkg 4 16 64 256 如需获取更多信息，请参阅[Isogeo目录中的元数据](https://open.isogeo.com/s/434296189d794266a04a8678e256f0c4/HiLeps3y1qrSx6aTDmKyp0spGPix0/r/5050e0e79ac1476f81df559edbd17306)。