Near-Scene Photogrammetric Measurement
Photogrammetry is the science of making measurements from photographs. Near-scene photogrammetric measurement is the science of making accurate measurements from photographs taken close to the object being photographed. Near-scene photogrammetry is used to measure difficult to access remote or dangerous environments such as steep slopes, open pits, deep water, and high cliffs.
The goal of near-scene photogrammetry is to obtain measurements that are as accurate as possible with the least amount of effort and cost. To achieve this, it is important to select the right photographic equipment, understand the types of measurements that can be made from photographs, and develop the skills necessary to make accurate measurements.
Photographic equipment is designed to take photographs of different sizes and at different distances. Most photographs taken for photogrammetric measurements are taken with a single-lens reflex camera. This type of camera has a single lens which allows the photographer to adjust the focus, angle and composition of the photograph.
The distance between the camera and the object being photographed will affect the accuracy of the measurements. The further away the camera is, the less accurate the measurements will be. It is important to have an accurate measure of the distance between the camera and the object being photographed to ensure accurate measurements.
The type of measurements that can be made from photographs depends upon the type of camera used and the number of photographs taken. For example, measurements of length, width and height can be made from the photographs taken with a single-lens reflex camera. More complex measurements involving angles and distances can be made from photographs taken with a stereo camera.
Once the type of measurements that can be made from the photographs has been determined, the photographer must develop the skills needed to make accurate measurements. Photogrammetric measurement is done by referring to a set of photographs taken from different angles and perspectives. The photographer must be able to interpret the elements in the photographs such as lines and angles in relation to one another and in relation to the objects being measured.
Once the photographs have been taken and the measurements have been interpreted, the photographer must calculate the measurements. Calculating the measurements involves using a software package designed specifically for photogrammetric measurements. The software package will allow the photographer to input the photograph data, enter the measurements, and generate a report of the measurements.
Near-scene photogrammetric measurement is an invaluable tool for measurement in remote or dangerous environments. With the right photographic equipment, a knowledge of the types of measurements that can be made, and the skills to make accurate measurements, a photogrammetric photographer can make measurements quickly, safely, and accurately.
