Depending on the question/problem at hand, there can be several instruments/data providers that can fulfill a client's needs. Knowledge of instrument characteristics and their relative positive and negative aspects is essential if one is to determine which kind of data to acquire or search for. However obtaining such knowledge is on a timeline that is often unrealistic for most clients. To illustrate this, a collection of imagery for an active volcanic region in the eastern Sierra Nevada of the state of California is provided below. This sampling of data reveals the abundance of remotely sensed data available in this region.

The increasing technological sophistication of remote sensing instrumentation over the past twenty years has culminated in the development of sensors that can provide users with data that can address many problems at once. This is accomplished in various ways, but one class of imagery illustrates this point best. The advent of imaging spectrometers or hyperspectral imagers in the mid-1980's ushered in a new paradigm for remote sensing. The following example shows how one dataset can be used to study a region in many different ways and address very different questions.

When deciding what the best form of imagery to obtain is in order to address a certain problem, issues of scale often arise. The scale length of the phenomena or process being observed is key as are the scale lengths available from the various sensors. The trick is to ascertain the best type of imagery to apply to a particular problem or study. Both vegetation and geological scale length issues are addressed.