Introduction: Sightline analysis has been around for a long time and has a variety of uses. Some examples of use are cell tower locations, construction site locations, real estate values, and archeology. The two main types of visibility models used are line of sight and field of view. Line of sight profiles model point-to-point visibility, while viewsheds model point-to-area visibility. (View Surface Analysis and Visualization, 2003) Viewshed analysis is used to calculate which locations in a digital elevation model (DEM) can be connected by an uninterrupted straight line to a viewpoint location at a specified distance. (Llobera, 2003) Using multiple viewsheds and combining them to create a cumulative viewshed is commonly used. A view where analysis focuses on understanding the relationship between points in isolation, and where concern about the space between the two is lost and deemed meaningless and inert. (Llobera, 2003) Cumulative viewsheds can be used to identify locations where the visual presence of elements may be greatest. (Llobera, 2003) My idea was to determine the visibility of hillside development by looking at it from the valley floor and to compare the hills on the east and west sides. Using small cumulative viewsheds, I can try to determine where the visual presence of houses may be most important. The “viewshed” model in Idrisi creates a 360-degree arc around the viewpoint point or area and calculates which cells in the surface image are visible. within the specified distance. Creating a continuous field of view of the area involved would be time consuming and not practical for the purposes of this project. .....underexploited areas. I gained a better understanding of vision basins and their complexity as well as a better knowledge of Irdisi's processes. Error that occurred: The reclassification sum files ended up being the same for trees and no trees, which gave me the same results and I had to go back and redo the analysis. I gained a better understanding of vision basins and their complexity and a better knowledge of Irdisi systems. process.BibliographyAnalysis and visualization of visibility surfaces. Caldwell, DR, et al. 2003. 2003.Joly, Daniel et al. 2009. A quantitative approach to visual landscape assessment. Annals of the Association of American Geographers. 2009, Vol. 99, 2, pp. 292-308. Llobera, M. 2003. Extending GIS-based visual analysis: the concept of visual landscapes. International Journal of Geographic Information Sciences. 2003, Vol. 17, 1, pp... 25-48.