In order to obtain scientific information, there are two methods to collect scientific data:
- In Situ (Field Measurements)
- Remote Sensing
Introduction
As per the National Ocean Service NOAA,
“Remote sensing is the science and art of obtaining information about objects or areas from a distance, typically from aircraft or satellites”, i.e, without being in physical contact with actual targets.
Why is Remote Sensing significant?
- It follows a systematic pattern for data collection (and avoids errors)
- Brings objectivity in data collection
- Repeatability: Repetition of information over a given space after regular time intervals.
- Offers a global coverage
- Remote Sensing is the only solution for inaccessible regions.
- It has a multipurpose role of mapping water resources, forestry, urban resources, and many more that can be of interest to different groups of people.
Note: With the onset of Remote Sensing, In Situ method is not discarded. We require In Situ measurements to check accuracy.
Remote Sensing Process
Step 1: To sense our object of interest, the target requires some source of energy (artificial/natural). The energy received by the target is either reflected, transmitted or absorbed (partially).
Step 2: A satellite containing a sensor absorbs the target’s reflected energy and records the information.
Step 3: The information captured by the satellite travels to the ground station when it is in direct line of sight with the station’s antenna.
Note: For the previous 3 steps, the information travels through the atmosphere to reach different destinations. The information is modified slightly everytime it comes in contact with the atmospheric layer.
Step 4: The information later is transferred from the ground station to an electronic device (computer) that discards any known errors and models the data. This information can also be termed as raw data which is cleaned and preprocessed before reaching the user.
