Data Products
The detection and recording of electromagnetic energy can be done photographically or electronically. Photographic processes utilize light-sensitive film to detect and record energy variations, while scanning devices capture images in digital format. It’s crucial to differentiate between “images” and “photographs.” An image refers to a pictorial representation, regardless of the energy regions used for detection, whereas a photograph specifically denotes images recorded on photographic film. Thus, all photographs are images, but not all images are photographs.
Remotely sensed data products are broadly categorized into two types based on the detection and recording mechanism:
- Photographic Images: These are obtained in the optical regions of the electromagnetic spectrum, ranging from 0.3 to 0.9 µm. Different types of light-sensitive film emulsion bases are used, including black and white, color, black and white infrared, and color infrared. In aerial photography, black and white film is commonly used. Photographs can be enlarged without losing information or contrast.
- Digital Images: A digital image comprises discrete picture elements known as pixels, each with an intensity value and a two-dimensional address. A digital number (DN) represents the average intensity value of a pixel, which depends on the received electromagnetic energy and the intensity levels used. The reproduction of object details in a digital image is influenced by the pixel size. Smaller pixels are beneficial for preserving scene details and digital representation. However, excessive zooming in a digital image can lead to information loss and pixelation. Digital image processing algorithms can manipulate the intensity levels represented by digital numbers in an image.
Chapter 6: Introduction to Remote Sensing| Class 11 Geography Practical Work
Class 11 Geography Ch 6 Introduction to Remote Sensing Notes: Introduction to Remote Sensing is the sixth chapter in CBSE Class 11 Geography, which discusses the concept of Remote Sensing and its various forms. The chapter explains how this technique works, its different methods, and how it’s used in various fields like geography, agriculture, and environmental science.
Students learn about the sensors used to collect data, like cameras and scanners, and how they create images and information about the Earth. They also learn how to analyze this data to understand changes in things like land use, vegetation, and the environment. Overall, the chapter helps students understand how remote sensing helps us learn more about our planet from afar.
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