Use of Interpretation Keys for Rapid Feature Identification (Selective and Elimination Keys) (Especially for GATE-Geospatial 2022)

Get top class preparation for competitive exams right from your home: get questions, notes, tests, video lectures and more- for all subjects of your exam.

Examrace Books on Mapping, GIS, and Remote Sensing prepares you throughly for a wide range of practical applications.

An interpretation key is a set of guidelines used to assist interpreters in rapidly identifying features. Determination of the type of key and the method of presentation to be employed will depend upon:

  • The number of objects or conditions to be identified;
  • The variability typically encountered within each class of features or objects within the key.

Generally, keys are more easily constructed and used for the identification of man-made objects and features than for natural vegetation and landforms. For analysis of natural features, training and field experience are often essential to achieving consistent results. Basically, an interpretation key helps the interpreter organize the information present in image form and guides him/her to the correct identification of unknown objects. Keys can be used in conjunction with any type of remotely sensed data. Such keys can differ from those employed in other disciplines in that they can consist largely of illustrations, e. g. landforms, industrial facilities, military installations. Many types of keys are already available if we can find or get our hands on them. This can often be very difficult and a reason people develop their own keys.

Remote Sensing. Ece 402 Unit-2

Selective Keys and Elimination Keys

Depending upon the way the diagnostic features are organized, two types of keys are generally recognized:

  • Selective keys are arranged in such a way that an interpreter simply selects that example that most closely corresponds to the object they are trying to identify, e. g. industries, landforms etc.
  • Elimination Keys are arranged so that the interpreter follows a precise step-wise process that leads to the elimination of all items except the one (s) that they are is trying to identify. Dichotomous keys are essentially a class of elimination key. Most interpreters prefer to use elimination keys in their analyses.

Developed by: