Orthophoto. Year 2012

Orthophotos Express 25 cm/pixel resolution of the PNOA (National Air Orthophotography Plan). Images in REGCAN95 compressed in ECW format of extension of 2,500 by 2,500 meters. This information is accompanied by a shapefile distributor where it is indicated in the area of the corresponding orthophotography. An orthophoto, or orthophotography, is a geometrically corrected aerial photograph (ortorectified). Unlike an aerial image, an orthophoto can be used to make real measurements since it is an accurate representation of the earth’s surface, in which the distortions inherent in aerial images have been corrected. Orthophotos combine the detail and temporal coverage characteristics of aerial photographs and the uniform scale and geometric accuracy of the maps.本数据集为PNOA（国家航空正射影像计划，National Air Orthophotography Plan）的正射影像速递（Orthophotos Express）产品，分辨率达25厘米/像素。影像采用REGCAN95坐标系，以ECW格式压缩，单幅影像的空间覆盖范围为2500米×2500米。该数据集配套提供矢量形状文件（shapefile），其中标注了对应正射影像的覆盖区域。 正射影像（Orthophoto，亦称正射摄影）是经过几何校正的航空摄影影像（ortorectified，即正射校正影像）。与普通航空影像不同，正射影像可用于实地量测，因其精准还原了地表形态，且校正了普通航空影像固有的几何畸变。正射影像兼具航空照片的细节表现力与时间覆盖特性，同时拥有地图的统一比例尺与几何精度。