CAMEL Category.JPG
If you know the general type of data you are looking for, begin your search with “Category.” Choosing “Category” in the second drop-down menu will populate the third drop-down menu with the names of categories that CAMEL uses to organize its data. These categories are usually defined by and named after map series, satellite imagery programs, topographic datasets, and survey missions. For example, popular categories that CAMEL receives data requests for are historical maps from the Survey of Egypt (“Survey of Egypt”) and high-resolution satellite Corona imagery from the 1960s-70s (“Corona”). You may also select "Subcategory" from the drop-down menu. “Subcategory” is a subdivision of a map series, satellite imagery program, topographic dataset, or survey mission. Example: the highest resolution Corona images come from the KH4A and KH4B missions, which are each subcategories within the Corona category. If you are interested in coverage of particular USGS products (of declassified Corona, for example), the USGS EarthExplorer website provides an index of un-referenced images.