Line of Sight Analysis


The Village of Oak Brook has recently contracted a design firm to
come up with some ideas for a corporate sign being added to an
intersection which conceals a few businesses. The design firm initially
came up with a sign that was 8 ft. tall and 15 ft. wide, which was to
be placed at the northwest corner of the given three way intersection.
In order for the sign to be added, some preliminary research also needed
to be done in order to test the feasibility of such a large sign being
added. The two primary factors that came into play were the underground
utilities located at the intersection and the signs visibility due to a
transformer box already located at the corner of the intersection. In
order to find out of the sign would be visible, Village engineers and
GIS staff were tasked with researching what size the sign would need to
be in order to be viewed from behind the transformer box.

By using the Village’s lidar point elevation data, the GIS
specialist was able to determine the approximate height of the
transformer box and the ground elevation of the proposed location for
the sign. The sign location was determined after all underground
utilities were marked in the field, and measurements were taken from the
curb to the closest spot free of utilities. Once the approximate
heights of the transformer box and ground elevations were determined,
the GIS specialist was then able to find the ground elevation of six
‘viewing’ points on the adjacent road, ranging from 135 to 710 feet away
from the proposed sign location. By then making a 3.5 ft. adjustment
to the ground elevation, we were able to determine the approximate
elevation that a typical person would be viewing the sign at. After
compiling the statistics, as shown in the image, it was determined that
the proposed sign would have to be at minimum 3 ft. taller than the
initial proposal. Without GIS, much, if not all, of this research
would’ve needed to be done in the field through the use of expensive
survey contractors or costly man hours taken away from the engineering
department. GIS was able to perform this analysis within a single day,
and provided multiple maps and tabular statistics supporting the