Remote Sensing and Image Analysis Flashcards
6 cards from real GISP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Remote Sensing and Image Analysis flashcards as text
The Kappa coefficient in accuracy assessment ranges from 0 to 1; a value of 0.85 indicates:
Answer: Strong agreement between the classification and reference data
A Kappa coefficient of 0.85 indicates strong agreement (typically interpreted as excellent), meaning the classification is substantially better than a random assignment.
Which phenomenon causes a single pixel in a multispectral image to contain the spectral mixing of multiple land cover types?
Answer: Mixed pixel (mixel) problem
Mixed pixels occur at boundaries between land cover types or when the spatial resolution is too coarse, causing a single pixel to contain reflectance contributions from multiple surface materials.
In Change Detection analysis using remote sensing imagery, what is the primary purpose of image-to-image registration?
Answer: To ensure pixels from different dates represent exactly the same ground location
Image-to-image registration aligns multi-temporal images so corresponding pixels represent the same geographic location, which is critical for accurately detecting true surface changes.
What remote sensing index is calculated as (Green - SWIR) / (Green + SWIR) and is primarily used to map water bodies?
Answer: NDWI (Normalized Difference Water Index)
The Normalized Difference Water Index (NDWI), developed by McFeeters, uses green and shortwave infrared bands to highlight open water features while suppressing vegetation and soil.
Which orbital altitude range characterizes most Earth observation satellites used for medium-resolution land cover mapping, such as Landsat and Sentinel-2?
Answer: Low Earth Orbit (LEO) at 500–900 km
Most Earth observation satellites like Landsat and Sentinel-2 operate in Low Earth Orbit (LEO) at altitudes of roughly 500–900 km, providing sufficient spatial resolution for land cover mapping.
When performing object-based image analysis (OBIA), what is the initial segmentation step designed to produce?
Answer: Homogeneous image objects that group similar adjacent pixels
Image segmentation in OBIA groups spectrally and spatially similar neighboring pixels into homogeneous objects (segments), which are then classified based on shape, texture, and spectral attributes.