Читать книгу Imagery and GIS - Kass Green - Страница 69

Millions of images have been taken of the earth, but not all of them are accessible. Current reconnaissance imagery is not shared broadly, and many archives of imagery exist but are not easily searchable. Actually obtaining imagery can be problematic because there currently is no coordinated repository for imagery metadata. Some datasets such as NAIP and Landsat are easily searchable on the web, downloadable, and dynamically served. Others, such as imagery in private photogrammetry company archives, are usually searchable and accessible only by contacting personnel at the firm.