SATELLITE IMAGERY & MULTISPECTRAL IMAGERY ANALYSIS: A CASE STUDY OF VOLTA LAKE OF GHANA




















The satellite imagery of Volta lake presents an original grayscale scene from Landsat 8 and Landsat 9, specifically using Band 1. This band captures data in the coastal and aerosol range of the electromagnetic spectrum. It is sensitive to fine particles and surface reflectance differences, which explains the strong contrast seen between bright and dark areas. The tonal variation suggests differences in land cover, moisture, and possibly suspended particles near the river. The map includes clear geographic coordinates, a small locator map of Ghana, and a legend showing reflectance values ranging from 70 to 958. This indicates that the dataset was not only radiometrically calibrated but also visualised to highlight fine variations in surface characteristics. It is a raw depiction of reflectance patterns without spectral enhancement.

The second map shows a processed multispectral analysis of the same region of the Volta River basin. Unlike the grayscale map, this map uses colour to represent different land and water features. The blue tones mark open water or areas with strong absorption in near-infrared wavelengths. The green tones point to vegetated surfaces, and the orange areas likely represent bare soil or mixed land cover with higher reflectance in shortwave infrared bands. This suggests that several Landsat bands were combined, through a false-colour composite. The map emphasises structural variation in terrain and land cover, showing clearer boundaries between water, vegetation, and less vegetated surfaces.

The grayscale image is useful for understanding the general distribution of surface brightness but does not easily distinguish between vegetation, soil, or water. Because Band 1 reflects mostly atmospheric effects and fine scale reflectance, it helps identify textural patterns but not detailed land cover categories. Bright regions in this image may correspond to exposed ground, built-up areas, or high-reflectance surfaces, while darker regions may represent water bodies or dense vegetation.

On the other hand, the multispectral image, by contrast, reveals much more about environmental conditions. The clear separation between blue, green, and orange areas shows that spectral information has been used to classify or enhance land cover differences. The strong blue region emphasises water masses of the Volta River system. The green region highlights vegetation, probably along the riverbanks and surrounding areas. The orange and yellow tones correspond to drier or less vegetated terrain. This enriched spectral view allows for assessment of ecological patterns, hydrology, and landscape structure that are not visible in the grayscale image.


Conclusion

Together, the two images show two stages of remote sensing analysis. The first presents original radiometric data in a single band, which is valuable for basic reflectance interpretation but limited in land cover discrimination. The second image demonstrates the advantage of multispectral processing, where combining several spectral bands produces clearer distinctions among water, vegetation, and soil. This improved clarity supports, environmental monitoring and makes it easier to understand spatial patterns along the Volta River.

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