LiDAR Visibility Analysis - Module 3

 This week we utilized ESRI Academy's learning plans to take several courses on visibility analyses and introductions to utilizing 3D information. I was able to learn several useful tircks that will quite possibly be useful in my endeavors ahead. These are visibility analyses. These forms of spatial analyses map the geographic areas that are visibile from one or multiple points on a geographic serface. 

There are two types of visibility analysis, the first is deemed a viewshed analysis. This where a raster is created which displays in binary value whether or not a cell is visibile from a vertain geographic location on the map. ArcGIS even has the capability to adjust the height of the individual or structure to display which pixels are visibile from the actual height of the feautre. A map of the visible areas from multiple locations are also possible. 

The second form of visibility analysis is deemed a line of sight analysis. This analysis determines whether two points in space are intervisible. Essentially, if one point on the map is looking directly at another point on the same map, is there anything that will be impeding the 'line of sight' from the observation point to the target point. This has a multitude of uses in especially in the world of surveillance and security. Once again, ArcGIS Pro harbors the ability to easily make these analsyes in its geogrocessing toolbox. In creating a line of sight map, one simply uses the create sightline tool and to create the 3D visibility lines and then plug the result into the line of sight analysis tool. This will then highlight the impeded lines of sight in red. These can be suqsequently removed by selecting by attribute ofthe impeded lines and then removing them. Below are some screenshots of my line of sight analysis. 

Observation points established, red line represents paradoue route that must be observed. 

Sight lines are established:

Line of sight analysis is run, areas where sightline is obstructed are in red. 

Areas out of line of sight are removed. 

Visible extent reduced to 600ft. 

The courses that were directed towards being an introduction to the use of 3D information discussed its adavatage as being a better tool to communicate certain forms of information. ArcGIS Pro has spatial analysis tools that are not only able to operate with 3D features but convert 2D images into 3D as long as there is some form of a digital elevation model to base the feature's height upon. Not only can these 3D scenes be created but they can now be exported and uploaded and opened on ArcGIS Online or Google Earth as scene layer package files (.slpk). Scene layer package files are created through the use of a geogrocessing tool which compiles all of the information within the 3D scene and allows those features to be recreated in the afforementioned outlets.