Archived Story

Council discusses aerial imagery

Published 5:36pm Friday, August 16, 2013

The public works committee met Thursday at city hall and heard a presentation from a geospatial solutions company on how LiDAR data could benefit the city.
LiDAR, which stands for light detection and ranging, allows specially equipped aircraft to create a picture of the surface terrain.
“We put a sensor in an aircraft and a laser pulse comes down out of it, hits the features on the surface and bounces back to the sensor,” said Jennifer Whitacre, senior program manager with Photo Science Geospatial Solutions. “It generates point data. This data is basically the building blocks of generating endless possibilities of things.”
This data can be used to generate end products such as slope analysis, flood pain mapping, line of site analysis and encroachment mapping for rights-of-way, to name a few.
Bradley Kruse, GIS coordinator, has submitted a budget request to have the data collected. Kruse explained that this bulk amount of data could help the GIS department assist other city departments.
“Our program is only good as our foundation,” Kruse said. “We have the software – we just need the data.”
Kruse explained that the resulting data set would be accurate enough to form 1-foot contour topographic maps with accuracy within 9 centimeters.
Councilmembers asked what the information could do for the city. Gerard Brewer, city engineer, said the imagery data would have multiple uses.
“For us, the topographic information would be indispensable,” Brewer said. “To be able to look at the city and know the true topographic lay of the city would be used routinely.”

Brewer noted that the high resolution imagery could be used for many construction projects, which require an initial survey.
Whitacre also noted that the data could be used to generate maps of building footprints, which Brewer said could help with maintenance records as information would be imbedded into the GIS map generated from the data.
The data could also help the city assess its storm water management plans.
The LiDAR data could map impervious and pervious surfaces, giving engineers an idea of potential storm runoff problems.
“We are beginning to have some downtown flooding and flash flooding at times, like a lot of cities,” Brewer said. “It would give us a tool to use to really assess our storm water situation.”
The data could also be sold, Whitacre said, to developers or those who need surveys done for construction projects.
Brewer noted that the last time aerial photography was performed in the city was in 2008.