Historical Digital Orthophotos since 1970 NW

Orthophotos are high-resolution, distortion-free, true-to-scale images of the Earth's surface. They are produced by photogrammetric methods in knowledge of the orientation parameters and with the addition of a digital terrain model from aerial images, which are available as vertical images. Orthophotos become historical as soon as they are replaced by DOP of current flight. Over the years, orthophoto production has been constantly adapted to changing needs and technical progress. Historical orthophotos can therefore differ in individual characteristic features. For example, color orthophotos have only been available since 1998, but there are also significant differences in ground resolution (10cm/pixel since 2014, 20cm/pixel from 2008 to 2013, 30cm/pixel from 1996 to 2007, 40cm/pixel before 1996). Orthophotos in the period since 1996 have been produced completely digitally, orthophotos from the years before have been created by scanning analog halftone prints from the DGK5 archive.