Learn Remote Sensing & GIS

How is Energy Transferred? The energy can be transferred in the three basic ways: conduction, convection, and radiation. The transfer of energy by electromagnetic radiation (EMR) is of primary interest to remote sensing because it is the only form of energy transfer that can take place in a vacuum (the region between the Sun and the Earth). The Sun bathes the Earth’s surface with radiant energy causing the air near the ground to increase in temperature. The less dense air rises, creating convectional currents in the atmosphere. Energy may be conducted directly from one object to another as when a pan is in direct physical contact with a hot burner. Energy Interactions When Electro-Magnetic (EM) energy is incident on any given earth surface feature, three fundamental energy interactions are possible.  Reflection (ER) Absorption (EA) Transmission (ET) Incident Energy (EI) = reflected energy +  transmitted energy + absorbed energy Three forms of Interactio

Sources of Electromagnetic Energy There are three main sources of  electromagnetic radiation that are used in  remote sensing:  Solar radiation (natural radiation from the  sun)  Terrestrial radiation (natural radiation  emitted by Earth's surface)  Artificial radiation (from a remote sensing  system) Solar Radiation The Sun yields a continuous spectrum of EM  energy. This Incident radiation can be reflected  from the Earth's surface. This process produces a large amount of  short wavelength energy (from 0.4 - 0.7 µm;  blue, green, and red light). It can also be emitted by the Earth's  surface. Such emitted radiation is typically  of a longer wavelength, in the middle and  far infra-red wavelengths. Interacts with the atmosphere and surface  materials (reflect, absorb).  Since the Sun has a much higher temperature  (6000 degrees K) than the Earth (303 degrees  K), so the overall energy radiated by the  Earth is lower and has its peak at a longer  wa

Contents Advantages Limitations Applications Advantages of Remote Sensing : Provides a synoptic view over a large region; Offers Geo-referenced information and digital information; Most of the remote sensors operate in every season, every day, every time and even in tough weather; Limitations : Can be expensive; Can be technically difficult; Not direct; Measure surrogate variables e.g. reflectance (%), brightness temperature, backscatter; Applications of Remote Sensing Urban & Regional Planning Scope: Mapping & updation of city/town maps  Urban sprawl monitoring Town planning Facility management  GIS database development Benefits: Better decision support, planning & management Rapid information updation Infrastructure development monitoring Spatial information analysis Agriculture Scope: Crop acreage estimation Crop modeling for yield & production forecast / estimation Crop & Orchard monitoring Soil sensing Mapping

Remote Sensing Process A. Energy Source or Illumination – the first requirement is to have an energy source which illuminates or provides electromagnetic energy to the target of interest. B. Radiation and the Atmosphere – as the energy travels from its source to the target, it will come in contact with and interact with the atmosphere it passes through. This interaction may take place a second time as the energy travels from the target to the sensor. C. Interaction with the Target – once the energy makes its way to the target through the atmosphere, it interacts with the target depending on the properties of both the target and the radiation. D. Recording of Energy by the Sensor – after the energy has been scattered by, or emitted from the target, we require a sensor to collect and record the EMR. E. Transmission, Reception, Processing – the energy recorded by the sensor has to be transmitted, often in electronic form, to receiving and processing station where the data a

Contents What is Remote Sensing? Need for Remote Sensing? Who uses Remote Sensing and Why? Remote Sensing :  The art & science of  acquiring, processing, and interpreting information (images and related data) about the Earth’s surface without  actually being in physical contact between the object and sensor. This is done by sensing & recording reflected or emitted energy  and processing, analyzing and applying that information. The images and related data are obtained from ground-based, air-or space- borne instruments that record the interaction between matter (target) and  electromagnetic radiation. " remotely" means using instruments (sensors) carried by platforms . Need For Remote Sensing Systematic data collection; Global coverage; Repeatability; Inaccessible areas – sometimes the only solution; Multi-purpose information Who Uses Remote Sensing & Why The geographer who looks for changes in the Earth’s surface

Welcome to my new blog. To begin with, I would highlight the  objective of the blog  briefly. When I first ventured into the field of Remote Sensing and GIS, it was a period when the subject was treated as a tool or device for solving geospatial problems. Even then it had the clout of an academic discipline, which was overlooked by a lot of mainstream academicians. Even now I find it amusing when this rich multi-disciplinary subject is referred to as a mere tool. Nevertheless, I will make a sincere attempt to take the discipline to as many enthusiasts and practitioners of Remote Sensing and GIS as possible in a simple manner.  The entire purpose of this blog will be to provide -  Document-based tutorials; Powerpoint presentations; Project development techniques; Dissertation guidelines; Book reviews; Sample test questions; Practical training (through youtube videos*); To conclude, I would give a brief  introduction  about me. I am a Remote Sensing and GIS professional with