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How to guarantee overlap when flying rooftops
How to guarantee overlap when flying rooftops

This article will cover the considerations that need to be made when flying rooftops or objects that are above ground level

Updated over a week ago


Flying a roof while taking off from the ground may present challenges. As the overlap of flight is calculated at ground level, even if you have factored in the height of the building for the GSD your overlap values will be much lower than the set values.

The following process will help you ensure the overlap values are correct, even at the roof level.

How to set up your flight

1 - Estimate the height of the roof.

  • For tilted roofs, note the height of the highest part

2 - Prepare your flight without taking the building into account.

  • For the height, do not use the total height for the flight. Start by introducing the height as if there was no building. For example, if you want to fly 34m above the roof, start planning the mission at 34m above the ground.

  • For the overlap, use the values defined as per the data product requirements.

  • Note down the estimate of the number of photos.

3 - Modify the mission to take the building height into account

  • Add the height of the roof to the height of the flight. If the roof is 10m high, add this to the 34m to get to 44m in total.

  • You will see that the number of photos will have gone down significantly at this stage.

  • You must increase both overlap values (front and side) until the number of photos reaches the previous amount calculated in point 2.

  • Do not forget to ensure the front and side overlaps have the same value. Typically, for a roof of 10m, the overlap will have to go from 80% to approximately 86% front and side.

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