How does the "Search THEMIS" tool find images within the latitude/longitude box that I define?
The "Search THEMIS" tool is supported by a database that contains the coordinates for at least six points (usually significantly more) outlining the edges of each available THEMIS image. The image will be included in the results table if any of these outline points falls inside your latitude/longitude box, and your remaining criteria are also met.
Note that the previous THEMIS query tool relied only on three coordinates per image; therefore, this new method may return more positive results for the same latitude/longitude box.