Topographical / elevation maps

General Discussion How To
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I am still a bit of a novice in this field and I am curious in what is recommended for best results for drone pilots have to create a topographical / elevation maps for clients. For example: flight settings, flight height, picture processing and then the specific exports that the client can use in AutoCAD or other tools. Your help is greatly appreciated!!

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Welcome to the forum. I think you’ll get allot of good information from the community. For a good topographic map your most important number is your GSD (Ground Sampling Distance).

  1. As long as you are at 1in/px (2-3cm) or better you are going to get good data.
  2. Get the right lighting. Obviously the times depend on where you are but we try not to have the sun at less than 20 degrees on the horizon or directly overhead. Fully overcast days are the best but you might need to turn on the Low Light option in Advanced Settings.
  3. Try to use Terrain Awareness if the site has more than a 30ft (10m) variation from it’s highest point to its lowest.
  4. For maps start with overlaps at 80 front and 65 side. Adjust the frontlap down to 75 if the battery savings makes sense.
  5. For crisp 3D models use the Enhanced 3D with crosshatch and perimeter. I cut the perimeter on really big sites. If the buildings/site has structures close together it would be a good idea to run a standard nadir flight to capture those in between spaces.
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Thank you MichaelL for your response. With respect to using the Enhanced 3D (with buildings), are you suggesting running 2 flights, one with 3D and another with nadir? And then uploading both sets for the same map processing?

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That’s correct. One standard nadir and then Enhanced 3D with crosshatch. This helps get ground data in between things that an oblique image can never see unless it happens to run down the centerline of that space. It’s particularly helpful on construction sites where you have project trailers, storage crates and the spaces where everyone parks.

I would only use the perimeter on projects smaller than 10 acres and/or if there are structures close to the property line. If it’s a construction with just one or a couple of buildings more towards the center of the site it’s just wasted space in my opinion. I would rather run a line around the structure specifically with Litchi or manual flight.