Lab 4 - Viewsheds

This week in Applications in GIS we took a look at viewshed and line of sight analysis. Most of the lab was completed in a 2D perspective but there were a couple of 3D components. All of the work was done using ArcMap and either the Visibility Tools in the Spatial Analyst Toolbox or the 3D Analyst Toolbox. Today my blog will focus on one of the 3D aspects of the lab.

We were provided with data for the Boston Marathon Finish Line to include the placement of one camera overlooking the finish line. We were asked to identify two other locations to place cameras to capture the happenings at the finish line based off of our viewshed analysis. The original camera was located to the west of the finish line at approximately 100 feet above the street next to a building with a 0-90 degree viewing angle. The two cameras I added are both located to the east of the finish line. I chose these locations based on the height of the building they could be attached because the viewshed was much more limited at ground level and for the different perspectives they would provide. The second camera (closest to the finish line) is located at a height of 194 feet and has a viewing angle of 150-260 degrees. I tried several different viewing angles but this angle created the largest area captured by all three cameras. This location also provides a decent birds eye view of the finish line. Third camera is located on a building one block to the east. It is positioned at a height of 117 feet with a viewing angle of 180-270. The locations of the three cameras capture the full finish line area from three different perspectives as seen in the graphic below.

Viewshed for Camera Placement Near Finish Line