Remote Sensing Basics
When we think of a map, the common image is of a road map or maybe a topographic map.
Both of these give a graphic representation of a specific area.
(Click on the images to see originals.)
|A road map is made from a series of vector files that delineate, surface features such as roads, cities, county and state boundaries, etc.|
|A topographic map is another type of vector map. In addition to the information found on a road map, a topographic map indicates surface geographic features like hills valleys, rivers, lakes and streams.|
With the development of satellites and satellite imagery, we now have a new method of mapping. With this new method we can get a photographic quality image that can be manipulated to show many different structures and conditions both on the surface of the earth and in the atmosphere above it.
|The technology allows the creation of visible color images that allow the detailing of water depths, sedimentation, healthy vegetation, soils.(TM 321)|
|Water boundaries, vegetation types and conditions can be shown as variations in hue (browns, greens, and oranges) as well as tones. (TM453)|
|Light reflectance from plants can be displayed as red. The naked eye can detect subtle tone variations as red colors. Information can be derived about the conditions and variety of vegetation.(TM432)|
|The images can also represent vegetation in familiar green tones and also indicate moisture content in vegetation and soils. (TM742)|
Satellite imagery is becoming an important problem solving tool in both the scientific and the business communities.
|Images can be used to show meteorological features (GOES, AVHRR)|
|smoke from forest fires (GOES, AVHRR)|
|and vegetation changes with time (AVHRR Composites).|
In order to be able to create, manipulate, interpret and understand what we are seeing in the images, we must first understand the Basics.