User:Mav/Data Acquisition in GIS notes by maveric149/2002-04-12 Lecture
Data Acquisition in GIS notes by maveric149 2002-04-12 Lecture
Remote sensing
[edit]Coined in the late 1940s
- two types: Active (Radar, SLAR, SNAP, sonar, LIDAR), and Passive (Landsat, Ikonos, GOES, Earth Imagin Satellites, Aerial photography, Sonar)
Resolution
[edit]Most important thing is that the resolution actually solve the problem. It will cost too much money to have too much resolution. Dimensions of Resolution 1) Spatial 2) Spectral 3) Radiometric 4) Temporal 5) Thematic
Spectral =
[edit]Type of energy
Moderate = black and white, High = IR, very high = used to detect mineral types.
IR light radiation is good to use to image vegetation -- the rays bounce off of internal structures within the leaf. Different species of plants will reflect at slightly different wavelinks.
Radiometric
[edit]Intensity of of energy or number of levels of brightness
Landsat has 256 levels of brightness, human eye can distinguish 120 and B&W film has 60 levels.
Temporal
[edit]None of the other dimensions of resolution matter if you miss what you are supposed to measure. In a low resolution temporal system, you may miss short lived phenomenon.
Thematic
[edit]Describes what specifically you are looking for, or its theme. Synthesizing general data to specific data that can be used to solve a problem.