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Require Photographs of Checkpoints

By NGP Standards and Specifications

Photographs will be required for checkpoints to help identify potential sources of error in the quality control process. There are currently no requirements in the Lidar Base Specification to provide photographs of checkpoints. 

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Status of this revision: Published in Lidar Base Specification 2020 rev. A

Photographs of checkpoints

Every checkpoint used to assess absolute vertical accuracy shall have a corresponding ground photograph with the following requirements: 

  • Photographs shall be captured at the time of the checkpoint survey.
  • Photographs shall be taken from each of the cardinal points (North, South, East, and West).
  • GPS survey equipment shall be in view so that the surrounding environment is recorded with respect to the point location being collected.
  • Photos shall be taken during daylight hours.
  • Photographs shall be of sufficient spatial resolution to enable interpretation of terrain undulations and vegetative cover surrounding the checkpoint for a minimum of 10 feet in all directions surrounding checkpoint.
  • All photographs shall be embedded and delivered in a single PDF document, preferably in the ground survey report.
  • Each photograph shall be labeled in the PDF with the checkpoint ID so that it can be readily located.