What is aerial Photography?
What is aerial photography? It’s simply aerial photography. This has made it difficult and expensive in the past. The genre has changed dramatically with the advent new technology.
The answer to the question “What is aerial photography?” was once “photography taken from a helicopter or plane”. This made it the exclusive preserve of a small group of experts. The genre has seen a radical democratization thanks to the advent of drone cameras.
This hobby, which began as a curiosity among the wealthy in the 19th century, has become a popular pastime for people around the globe.
This article will be about: 1. Introduction to Aerial Photography 2. Characteristics of aerial photography 3. Interpretation.
Introduction to Aerial Photography
Aerial photography is photography taken from the air. Aerial photography can be described as one of the most versatile, economical and common forms of remote sensing. It can be used to fix time within the space-time framework. Aerial photography was used in remote sensing for the first time, and it is still being used today with electronic scanners and satellites. Aerial photos will continue to be the most popular type of remote sensing data.
As early as the mid 1800s, aerial photographs were taken using balloons and kites. Gasper Felix Tournachon, an 1858 pilot of a balloon, took the first ever aerial photo from a balloon at 1,200 feet above Paris. Any type of camera can be used to take aerial photographs. Aerial photography has been used in many successful applications using handheld 35mm cameras on light aircraft.
High geometric and radiometric accuracy is required for large area studies. Only purpose-built cameras can achieve this. A smaller-scale photograph will show an object as smaller than a larger one. A larger scale aerial photo will give a more detailed view of a smaller area. Aerial photography can be used for land-use planning, mapping, geologic mapping, species habitat mapping, and integration into GIS.
Characteristics of aerial photography:
i. Synoptic Point:
Aerial photos give us a bird’s-eye view of large areas, allowing us to see the spatial context in which they are located. These photographs enable us to detect small-scale features and spatial relationships that are not possible on the ground.
ii. Time Freezing:
These records are almost permanent records of the Earth’s surface conditions at one time and can be used as historical documents.
iii. Capability to stop Action
They are helpful in studying dynamic phenomena like flooding, moving wildlife and oil spills, as well as studying how they affect traffic and forest fires.
iv. Three Dimensional Perspective
It gives a stereoscopic view on the Earth’s surface, and allows for measurements both horizontally and vertically. This characteristic is missing in most remotely sensed data.
v. Spatial and Spectral Resolution:
Aerial photos are sensitive to radiation at wavelengths beyond the human eye’s spectral sensitivity. They are sensitive to objects beyond the spatial resolution power of the human eye.
You can easily access aerial photographs at many scales to see much of the world.
These are usually cheaper than field surveys, and often more accurate than maps.
Aerial Photo Interpretation
Aerial photographic interpretation can be defined as the act or process of looking at photographs from the air in order to identify objects and determine their significance.
The seven tasks that the aerial photo interpreters are usually responsible for during the interpretation process include:
ii. Recognition and identification
vi. Accuracy determination.
All aerial photos have the advantage of being able to be taken in stereo pairs, which can give a perspective or 3D view of the terrain. Most common instruments are the pocket stereoscope (or mirror stereoscope), scanning stereoscope, and interpreter scope.
These are the basic characteristics of a photograph that an interpreter will use:
i. Tone (also known as Hue or Color):
Tone is the relative brightness of an element in a photograph.
It is important to consider the size of objects in relation to the scale of a photograph. This will allow you to identify the object.
It is the general shape of objects. Regular geometric shapes are often indicators of human presence or use. Some objects can be identified just by their shape.
Frequent changes in tone in photographs can give the impression that image features are smoother or more rough.
v. Pattern (Spatial Arrangement):
A photo’s patterns can help you identify objects, e.g. Random pattern created by unmanaged trees and evenly spaced rows by an orchard.
Shadows are used to aid in the identification of heights in aerial photos. Shadows can also hide objects within them.
It is a topographic or geographical location. This is a key characteristic for identifying landforms and vegetation types in photographs.
It refers to certain features occurring in relation to other features.
It’s the science and technology that allows you to obtain spatial measurements from aerial photos. Photogrammetric analysis can be used to determine distances, area and elevations with hardcopy (analog), photographic products, equipment, and simple geometric concepts. It can also be used to generate precise digital elevation models using digital images and other analytical techniques. Preparing topographic maps is one of the most common uses of photogrammetry.