Viewshed: What is it?

A viewshed is defined as an area that’s visible to the human’s naked eye from a specific location. All the surrounding points within the line of sight that can be viewed without any obstruction due to an obstacle on the terrain are counted in the viewshed. To put it in simple terms, viewsheds refer to the place or cells in the rasters that an individual can easily view from one or multiple points. You may need to use viewshed when it is important to track the visibility of a certain object. In simple words, it helps you identify how visible a particular object is from a specific location. For example, the archeologist might use this concept to see how the water tower will look from a specific location or if it is placed in a certain location. It gives you a clear idea of how the view will be from the road or other viewing spots. GIS and Viewshed With the help of the GIS (geographic information system), you can determine which objects can be located from a specific location or which observing point gives you a clear and unobstructed view of the object in question. GIS also helps you identify the areas that are within your eyesight based on the prehistoric conditions. It is important to note that a viewshed does not necessarily have to be visible to human eyes. The viewshed is also found in the radiocommunication industry to locate the areas where certain transmitters or the combination of the antenna and other tools can help you get the best signal. The most common application of viewsheds is in the public areas. These are calculated for the public roads, high-rise buildings, and other public properties that need proper measurement. It is also called visibility analysis. As mentioned earlier, the concept is popularly used for identifying the capabilities (the areas that can be seen) as well as vulnerabilities (what cannot be seen with the naked eyes). That’s what the visibility analysis helps you locate. GIS tools are used to divide the line of sight into parts - visible and invisible sections. This gives users a clear picture of the objects that are visible for a specific point (observing point) and the objects that can’t be seen. The simplest definition of the viewshed is identifying objects that are in sight from a specific distance. However, there is a difference between the viewshed and the line of sight. The former is used to indicate only the areas that are visible to the human naked eye from the observer’s point of view while the line of sight is used to create two separate sections showing the obstructed and unobstructed view. Like other applications of the geographic information system, the viewshed is commonly used for public places, military, and construction applications. Imagine getting clear of the roads, heights, and other items from your viewshed. It will be easier to differentiate between the obstructed and unobstructed views and get a clear picture of the things ahead of you.