This range is caused more by the limitations of the equipment than by ecological reasons. It is within the range of the EMS that is most desirable for ecological studies. These pieces are combined to form a spectrograph. While camera systems such as the DMSV can sample a large area, the spectroradiometer is intended to sample a single point, or pixel. Spectrographs can be used to identify portions of the EM spectrum that are of the most interest for a given project.
Imagery taken by the DMSV is comprised of pixels.
Each pixel has four datums associated with it, representing the four cameras used to photograph a given site. The spectroradiometer samples a single pixel across a range of EMS values, many more than the 4 points than the DMSV samples. Spectrographs allow the DMSV to be utilized with greater efficiency. It should be noted that spectrographs are not constant. The signature for a plant species can change with the time of day, season, year, environmental conditions, or other factors.