Remote sensing is the process of acquiring details about an object without physical on-site observation by satellite or aircraft. Remote sensors are mounted on the aircraft or satellites to collect data by detecting the energy reflected from the Earth. Remote sensing has been useful to scientists who constantly need data regarding the earth, the ocean and the atmosphere.
History of remote sensing
The field of remote sensing has undergone numerous advances in recent years as the field of photography and aircraft innovation have facilitated the development of the discipline. It was not until 1960 that the term remote sensing was adopted. Before this, the term “aerial photography” was the common term used. Aerial photography at the time represented black and white images and new technologies and methods were emerging that promoted more detailed graphic images. Computer technology has also enabled a digital form of images. During the 1960s and 1970s, the United States and Russia favored aircraft over airplanes, as they could regularly monitor.
Overview of remote survey
Remote sensing can be performed by remote passive or active sensors. Passive sensors collect radiation from external stimuli. They respond to the energy reflected from the earth’s surface. The primary source of energy invoked by passive sensors is reflected sunlight. Radiometers, infrared and photographic films are examples of passive remote sensors. Active sensors, on the other hand, depend on internal stimuli for data collection. They reflect energy for the particular area and, after detection, measure the energy reflected from the region. Examples of such sensors include the Lidar, which projects the laser light to measure the distance to a target. One of the most important satellites that allowed remote sensing is Landsat, a project conceived in the United States. Since its launch,
Applications of remote sensing in geography
Remote sensing helps people acquire information on Earth. Hazard assessment and monitoring of land degradation and conservation is therefore essential. The system keeps track of bad weather, floods, earthquakes, hurricanes and the data collected can be interpreted to analyze the destruction caused by natural disasters. These data can be used to formulate strategies to be implemented before and after disasters. Because the system can access areas that are inaccessible to humans, it can monitor the impact of deforestation on significant regions (including the Amazon basin) and can also map areas that need protection. The system is particularly essential in environmental monitoring and in the management of natural resources and analyzes the human impact on the environment. Remote sensing is also useful in oceanography as it keeps track of ocean circulation, temperature and wave height to better understand ocean resources. The system is used in geology and mining exploration, forestry and agriculture.
Remote sensing limitations
The resolution of the images produced by the satellites can be too coarse to identify small areas of contrast and undertake a detailed mapping. The process of analyzing the collected data is complicated and expensive and the measurement uncertainty is often extensive. The costs of operating a remote sensing system can be expensive, especially for small and developing countries with inadequate finances, technological gaps and lack of qualified personnel.
