Photogrammetry: A guide to good practice

Photogrammetry is a field of technology in which photographs are used for various kinds of measurement. Photogrammetry can be used to determine the exact positions of geographical features (for example for topographic maps), and to create rotatable 3D models of photographed objects or various types of 3D visualizations. This guide aims to provide guidance on what to consider both before and during the documentation and archiving of datasets produced using digital photogrammetry. The guide covers common file formats used for storing photogrammetry files and which of these are suitable for archiving. The guide also discusses archiving strategies that can be used to ensure that the quality of photogrammetry files is maintained after preparation for archiving. The guide builds on existing documentation standards and describes the photogrammetry data that is considered to be important to preserve for future use. 

Photogrammetry can be performed from a long distance, for example from a drone or an aircraft, or at close range with a handheld camera or a camera on a tripod. Data collection with drones or aircraft often results in exceptionally large data sets and requires (to some extent) different data management than data collected with ground-based photogrammetry. The guide is therefore limited to ground-based photogrammetry, performed at close range with a digital camera. 

Structure-from-Motion (SfM) is a common branch of photogrammetry. SfM is based on the same principles as other photogrammetry and aims to create 3D models but is more user-friendly and has lower accuracy requirements. For example, SfM does not require camera calibration or advanced camera equipment. The guide is also aimed at people working with SfM, and the information about file formats, metadata and significant properties is the same for anyone working with photography-based 3D reconstructions, regardless of the level of accuracy.