remote sensing and its applications by lra narayana

The term ‘spectral signature’ is sometimes used to describe the spectral response curve for a study target. In some instances, the interaction between incident radiation and earth’s surface object will be different from time to time, such as might be expected in the case of vegetation as it changes from the leafing stage, through maturity growth and, finally to senescence. The spectral reflectance can be affected by many factors such as soil nutrients, the growth stage of the vegetation, the color of the soil (which may be affected by recent weather conditions). A basic assumption made in remote sensing is that specific study targets (different types of soils, water having different degrees of impurities, rocks of different lithologies, or vegetation of various species) have an individual and characteristic manner of interacting with incident radiation that is described by the spectral response of that study target. Land-cover and land-use maps are required for many applications such as regions planning, landscape planning, and landscape ecology, agricultural management, and forestry.Įlectromagnetic energy reaching the earth’s surface from the Sun is reflected, absorbed or transmitted. The passive sensor is superior within the field of technical observation of the planet, such as Multispectral and Hyperspectral technology. Passive sensors are more used because it provides great quality satellite imagery. Examples of passive remote sensors are photography, infrared, and radiometers. Sunlight reflection is the most common source of radiation measured by passive sensors. The sensors gather radiation that is emitted or reflected by the object or surrounding areas.

RADAR and LiDAR are examples of active remote sensing which measure the time delay between emission and return. Active sensors throw their own energy to scan the object. The sensor embodies within itself the source of illumination like a satellite equipped with a RADAR sensor. This is done by capturing the reflected radiation/energy. Remote sensing is the process of acquiring information, detecting, analyzing, monitoring the physical characteristics of an area by recording it is reflected and emitted radiation energy without having any physical contact with the object under study. Remote that means something which is not exactly in contact or physical contact, Sensing means getting information, data something like temperature, pressure, photograph, etc.

Remote sensing and its applications by lra narayana