Sherwood Surveying & SUE, a sister company of M&S Engineering, is now offering Aerial Photography and Drone Mapping Services. Photography, instead of LIDAR, uses multiple photos with overlapping angles to prepare a representation of the Earth’s surface. The use of a drone and photography allows us to utilize the cutting-edge photogrammetry software in order to create detailed topographic surveys, ALTA surveys, 2D orthophotos, and 3D digital terrain models, as well as can allow us to cut down the time it takes to complete a survey.

Our team includes pilots that are commercial licensed & FAA Part 107 Certified and a UAV (Unmanned Aerial Vehicle) that is commercially registered with the FAA and insured. Our expert team is capable of providing you with HD aerial photography and videos across your site. Our UAV is also capable of meeting your needs for Power Services Inspections, Telecommunication Tower Inspections, and Volumetric Analysis of Mining Operations.

Aerial Surveying is not new. This technique, formally known as “Photogrammetry” has been around since WW II. Today with the use of GPS and recent advancements in automated technology, the drone has evolved into a very powerful tool for the future of surveying.

Lots of people are now operating Drones out of there house as a small business, but without the professional oversight of surveyors. All surveys prepared by Sherwood are governed by Texas Board of Professional Land surveyors and under the direct supervision of an RPLS. We hold our drone data to these same professional standards.

The Drone used by Sherwood is registered through FAA as an UAV Unmanned Aerial Vehicle. It by law, has to be operated by a licensed pilot at all times. We currently have 2 licensed Pilots on staff. Our pilots go through a preflight check list as required by FAA for any flight. We keep very organized records of all of our flights.

Our current drone utilizes a specialized camera & flight program to survey the earth via photogrammetry techniques rather than LIDAR. Photogrammetry uses multiple photos with overlapping angles to prepare a representation of the Earth’s surface.

Before starting any drone project, we first screen the site’s conditions to see if it is favorable for photogrammetry & the drone’s capabilities. Heavy trees & tall grass are restrictions. Google earth or actually driving a possible site helps us pre-screen for these possible types of restrictions. Weather is also a factor that is on the preflight check list and our pilots must be aware of to conform with FAA standards. The drone is not safe to fly at night, in extreme cold, or extremely windy conditions.

Before any flight we check to confirm that the site is in a safe airspace per FAA Sectional Airspace Charts. Although we fly at low altitudes (never to exceed 400’), if a site is located in a controlled airspace, we still by law confirm with those regulations. There are new rules about this issue being reviewed that should open up more areas of these controlled airspaces specifically for drones and this kind of work.

Once, we have reviewed all possible restrictions and feel the site is safe to fly, we go about planning our flight.

A flight pattern is set up using a specific Flight App we utilize called “Map Pilot.” We still set ground control points / Aerial Targets, measure property corners, and tie in structures that cannot be seen by the drone from the air with conventional surveying equipment (such as a Total Station & GPS).

Once a flight plan is created and started, the drone lifts off the ground and the flight app takes over (similar to auto pilot) to maintain a constant altitude and flight path. It then flies along each line at a constant steady speed, recording HD photos of the ground, from directly overhead and overlapping angles. Although the drone is programmed via the Flight Apps, the pilot has direct control of the aircraft at all times, and must keep drone in line of sight, always monitoring for possible hazards and air traffic.

Photos are then essentially “meshed” together to create a 2D Orthophoto Aerial Overlay, and a 3D Digital Terrian Model of the site, from which survey grade data can be extracted. Not only does the drone provide greater accuracy, but it reduces time needed to accomplish projects. For example, a topographic survey was prepared of a 176.56 acre tract near Lockhart, Texas. The “on the ground survey” took about 3 days via traditional surveying equipment. The drone survey of the same site took about half a day.

3 miles of road survey took 5 days using ground and Drone Survey. Without the drone, it would’ve easily taken 10 days or more. Some traditional ground survey equipment is still needed to pick up objects under trees, corners of buildings, water meters, utility boxes,and  manholes. To maximize accuracy for our clients, we combine both drone & traditional data to complete surveys.

By flying at high altitude, the camera can easily capture photos outside our immediate property line. If for some reason we needed to fly over private property, we will ask for entry as needed. Our drone is optimized for projects such as roadways, parking lots, mining facilities, construction, and open properties with trimmed grass / vegetation. The drone’s HD photography can not only be used on overhead electric lines to inspect the lines, towers, insulators, but is extremely effective for inspecting roofs, water towers and other tall structures.

For additional information contact:

Cody Emanis, S.I.T. 
Sherwood Surveying & S.U.E.
6477 FM 311, PO Box 970, Spring Branch, Texas 78070
O (830) 228-5446
www.msengr.com
www.sherwoodsurveying.com
cemanis@sherwoodserveying.com