The Aerial Survey Section is responsible for acquiring aerial imagery and producing geospatial information products using photogrammetric processes for use in planning, design, construction, and maintenance of INDOT properties, facilities, and roadways. The information is collected by using one of many small Unmanned Aerial Systems (sUAS) that the section has. Photogrammetry is the art, science and technology of obtaining reliable information about physical surface features by recording, measuring and interpreting aerial photographic imagery. Photogrammetry uses precision aerial cameras to photograph the desired project areas.
The Aerial Survey Section also provides Light Detection and Ranging (LiDAR) services using sUAS. LiDAR data is collected by a sensor sending out hundreds of thousands of light pulses, or lasers, a second. The reflected light is then collected by the sensor. The LiDAR sensor calculates the time it took the various light pulses to return to the sensor and converts that into a distance. This information creates a 3D map of the area that it captures.
Below is a list of services that the Aerial Survey Section provides.
Aerial Survey Services
Photogrammetry
As previously mentioned, the Aerial Survey Section collects photogrammetry for INDOT and other state departments using sUAS. For photogrammetry, many pictures are taken of the project area. Each photo is overlapped with multiple photos on all sides. The photos, camera specifications, and location data are processed together. The images then get stitched together into one product that is accurate in size, scale, location, and elevation. The orthomosaics that are created from photogrammetry can be used for many things, including mitigation, measuring distanced/areas, supplemental survey support, and asset management.
3D Models/Maps
3D models/maps can also be created using photogrammetry. This uses the same concept as an orthomosaic, but a 3D model is created. A 3D model of a project can provide information wanted that a 2D map will not provide. Some examples are cuts, fills, volumetric measurements of stockpiles, and can help get a better understanding of the area that was captured.
If a detailed 3D model is needed, such as a specific building, bridge or other feature, more saturation would be required. Along with that, handheld camera photos can be combined with aerial photos to get good coverage.
Light Detection and Ranging (LiDAR)
As mentioned before, LiDAR data is collected by a sensor sending out hundreds of thousands of lasers per second. When the lasers reflect off of an object, the light goes back to the sensor. The sensor then calculates the time it took the laser to return. With that information, it can calculate the distance from the sensor. Since the sensor is georeferenced, the point that the laser hit can be georeferenced. After millions of points are collected throughout a project, a LiDAR point cloud can be created.
LiDAR is most useful in vegetation when compared to photogrammetry. This is because anywhere direct sunlight hits, so to can the LiDAR laser pulses. A good visual example is looking straight up through a tree. When someone looks up through a tree, there are bits of sky/sun that poke through. The lasers from the LiDAR can also poke through those holes. Photogrammetry does not do this because it utilizes pictures instead of direct points.
The Land and Aerial Survey Office also has the ability to use a terrestrial LiDAR sensor. This uses the same concept as the aerial LiDAR sensor, but the data is collected from the ground instead of the air. A terrestrial LiDAR sensor is beneficial when the data that is needed is hard to get from an aircraft. Some examples are sides of buildings, the underside of bridges, and tunnels.
Simple Photography/Videography
Along with photogrammetry and LiDAR, the Aerial Survey Section can also provide more simple photos and videos from the ground and aerial perspectives. Although the Aerial Survey Section has this capability, many times each department/district has a team that can also provide this service.
UAS Program Assistance
As sUAS professionals, the Aerial Survey Section wants the use of drones in Indiana to expand, especially in state departments. Because of this, we are willing to help assist Indiana departments, offices, and districts develop a sUAS team/program. We, along with the Aviation Office, are more than willing to help with this type of development.
Statewide Orthomosaics
The State of Indiana provides public, statewide orthoimagery in three-year cycles. The state is split up into 3 sections running north/south. Each year, one of these sections is flown by a manned aircraft with a camera to collect imagery to create an orthomosaic. The resolution is 6 inches statewide, with the options for municipalities to purchase 3 inch resolution. The Aerial Survey Section assists with the quality control of this project.
Contact Information
Douglas Heidenreich
Aerial Survey Coordinator
Indiana Department of Transportation
120 South Shortridge Rd.
Indianapolis, IN 46219
dheidenreich@indot.in.gov
Mark Shambaugh
Imaging Technician-Aerial Survey
Indiana Department of Transportation
120 S. Shortridge Rd.
Indianapolis, IN 46219
mshambaugh@indot.in.gov
Jonathan Schiemann
Lead Stereo Compiler-Aerial Survey
Indiana Department of Transportation
120 S. Shortridge Rd.
Indianapolis, IN 46219
jschiemann@indot.in.gov
Jennifer Waymon
Stereo Compiler-Aerial Survey
Indiana Department of Transportation
120 S. Shortridge Rd.
Indianapolis, IN 46219
jwaymon@indot.in.gov
Cole Bramel
Survey & Remote Sensing Technician
Indiana Department of Transportation
Land & Aerial Survey Office
120 South Shortridge Road
Indianapolis, Indiana 46219-6705
cbramel@indot.in.gov