secondary planet
3.On the other side, as far as the development of the secondary planet remote sensing and the aerophotography, we get more and more geographic information from the remote sensing . Especially, as the maps from small high resolving power satellite become using in business, remote sensing image becomes to an important data source for GIS.
4.Digital Orthphoto Map(DOM) is a collection of digital orthphoto data of scanned digitalizational aerial images or secondary planet images data from high altitude,of which reflection errors are rectified and enchased pixel by pixel by Digital Elevation Model(DEM),and which are cut on national basic map scale and relief map range.
