Visibility Analysis

This week we used Esri courses to learn about visibility analysis.  Visibility analysis can be used for many things, such as determining sight lines from observer points to target areas or what regions a grouping of security cameras can or cannot see.

This is a linked view of two separate perspectives of the same map.  Moving around one map replicates the same movement in the other so that they match. 

3D is often used for this type of analysis.  It is useful for being able to see multiple viewing angles and understanding the nature of the terrain.  For some maps it makes more sense to use photorealistic imagery and for others it is fine to use more simplistic symbology.  The purpose of the map and the intended viewer influences these decisions.

A scene with 3D buildings and trees.  The goal of this task was to use the global scene feature to explore light and shade at different times of day.

Using GIS to create lines of sight has a wide range of uses.  For example, if a company was looking to build a hotel and wanted to know where to buy land that had the best observation points for well-known landmarks line of sight analysis could be used for determining this.

A demonstration of lines of sight for a parade going through Philadelphia.  This sort of map can be used for knowing where to place security officers so that no section of the parade is in a blind spot.

View shed analysis is another method of using GIS for visibility.  It takes into account what areas are covered by the view shed with regards to things like terrain.  This sort of analysis is commonly used when figuring out where to place security cameras so that all areas of interest are covered.   

This map shows the boundaries of a park and the four lampposts.  The area in white shows where at least two areas of light overlap from two different lampposts.

3D scenes can be exported and shared with others to make projects more easily accessible.