The main idea is how a remote-sensing sensor collects information about an area . A sensor does not simply take an ordinary photograph. It measures the electromagnetic energy reflected or emitted by objects in different wavelength bands . Depending on how many bands are measured and how the sensor collects them, different imaging systems are used. 1. Multispectral vs. Hyperspectral Multispectral imaging (MSI) records information in a limited number of relatively broad, separate spectral bands , such as blue, green, red, near-infrared and shortwave infrared. Hyperspectral imaging (HSI) records information in many narrow and usually contiguous spectral bands . Therefore, it provides a much more detailed spectral signature of each pixel. The resulting dataset is commonly called a hyperspectral data cube (hypercube) because it contains: X-axis → spatial information Y-axis → spatial information Z-axis → wavelength/spectral information Thus, hype...
Areal Differentiation means the study of how and why different places on the Earth's surface are different from one another . Geographers study: What phenomena are distributed in an area — physical and human. Where they occur . How they are related to each other . Why their distribution differs from place to place . How these differences create distinct regions . Simple example Kerala and Rajasthan are different because of differences in: Climate + relief + soil + vegetation + population + agriculture + culture → different geographical characteristics. Therefore, Areal Differentiation asks: “Why is one area different from another?” Core Concepts A. Area A portion of the Earth's surface where particular geographical phenomena occur. B. Region An area having some common or distinctive characteristics . C. Homogeneity Sameness or similarity within a region. Example: An area having similar rainfal...