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Location – Where the object is found on the map or photo. Knowing the place can give clues about what it is.
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Size – How big or small it appears, which helps identify objects (e.g., a football field vs. a garden).
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Shape – The outline or form of the object, such as round, rectangular, or irregular.
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Shadow – The dark area an object casts; it helps guess height, shape, and type of object.
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Tone/Color – Lightness, darkness, or color differences that help tell objects apart (e.g., blue water, green vegetation).
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Texture – How smooth or rough the surface looks in the image (e.g., forest appears rough, grassland appears smooth).
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Pattern – The arrangement or repetition of objects, like rows of trees or grid-like city blocks.
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Height/Depth – How tall or deep an object or landform is, often estimated from shadows or stereo images.
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Site/Situation/Association – The surroundings and relationships between objects (e.g., a swimming pool next to a house, or a factory near a railway line).
Remote sensing indices are band ratios designed to highlight specific surface features (vegetation, soil, water, urban areas, snow, burned areas, etc.) using the spectral reflectance properties of the Earth's surface. They improve classification accuracy and environmental monitoring. 1. Vegetation Indices NDVI – Normalized Difference Vegetation Index Formula: (NIR – RED) / (NIR + RED) Concept: Vegetation reflects strongly in NIR and absorbs in RED due to chlorophyll. Measures: Vegetation greenness & health Uses: Agriculture, drought monitoring, biomass estimation EVI – Enhanced Vegetation Index Formula: G × (NIR – RED) / (NIR + C1×RED – C2×BLUE + L) Concept: Corrects for soil and atmospheric noise. Measures: Vegetation vigor in dense canopies Uses: Tropical rainforest mapping, high biomass regions GNDVI – Green Normalized Difference Vegetation Index Formula: (NIR – GREEN) / (NIR + GREEN) Concept: Uses Green instead of Red ...
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