What is Remote Sensing?

https://svs.gsfc.nasa.gov/13259

 Another discussion topic from the new course at SAIT.

• What is remote sensing and how do you foresee using remote sensing in the industry?
• What makes interpreting remote sensing imagery different than looking at a photograph?

Remote sensing is the art and science of studying the earth without touching it (SAIT, n.d.).  A simple example of a commonplace application in everyday life is a photograph (James B Campbell & Randolph H Wynne, 2012).  When we take a picture, we observe an object, but we never actually touch it.  In this case, we are capturing a portion of the EM spectrum, the portion that is visible to us, that is reflected from the object.

 

Remote sensing from the standpoint of GIS is more than a simple photograph, for example, satellites in orbit collect information across the entire EM spectrum allowing us to see more information than our eyes are capable of.  Remote sensing can be completed in a myriad of ways such as through satellites, aircraft, and UAVs. These platforms can carry a wide array of sensors allowing us to capture many different forms of energy.

 

Part of being able to make maps and analyze spatial data requires the capture of this data.  Sometimes this can be accomplished by geo-referencing paper maps and digitizing them.  Remote sensing can provide us with another data source that can allow us to update maps as well as provide additional thematic information (SAIT, n.d.).

 

Much analysis that we need to do about our world requires data that is more up to date.  Using EM spectrum data can allow us to identify ground cover, crop types, forests, and a myriad of other aspects of the ground (James B Campbell & Randolph H Wynne, 2012).  Through the analysis of an object's unique spectral reflectance, we can ascertain what we are looking at, but it is important to recognize the limitations of this technique as spectral reflectance changes over both time and space (James B Campbell & Randolph H Wynne, 2012).

 

An example of using remote sensing within the industry that I came across is the WildFireSat project.  Canada is preparing a new satellite mission, WildfireSat, to help us better maintain and understand wildfires.  This system will use infrared sensors to monitor wildfire energy output Fire Radiative Power (WildFireSat: Enhancing Canada’s Ability to Manage Wildfires | Canadian Space Agency, 2022).  

 

Although a photograph is a form of remote sensing, other forms are a little more difficult to interpret.  We see the visible spectrum every day so its observation is intuitive to us.  Choosing the correct bands of the EM Spectrum to display.  EM Spectrum Data from LandSat satellites consist of 8 different bands of EM data, 3 of which we can see leaving five bands of information we can’t see(GIS Geogrpahy, 2021).  Before any analysis can be done the user first needs to know what combination of bands will be needed for the analysis, such as layers 6, 5, and 2 for agriculture or layers 7,6, and 2 for geology (GIS Geogrpahy, 2021).  Finally, once the bands have been selected the user will need to analyze what they are seeing using a combination of experience and knowledge to make sense of it (SAIT, n.d.).

 

Works Cited

GIS Geogrpahy. (2021, June 4). Landsat 8 Bands and Band Combinations. https://gisgeography.com/landsat-8-bands-combinations/

James B Campbell & Randolph H Wynne. (2012). Introduction to Remote Sensing (5th ed.). Guilford Publications.

SAIT. (n.d.). GEOS451—Lecture1 RS Process.

WildFireSat: Enhancing Canada’s ability to manage wildfires | Canadian Space Agency. (2022, May 12). Government of Canada. https://www.asc-csa.gc.ca/eng/satellites/wildfiresat/default.asp