Evaluation of spectral indices in monitoring land use changes in the city of Wasit, Iraq

Evaluation and analysis of changes in environmental variables is an important step in the direction of presenting the components of management decisions. The use of spectral indicators is one of the methods of evaluation, analysis and monitoring of changes. In this research, to evaluate land use changes in Wasit city, in order to investigate the process of land use changes and vegetation, first, images of 3 periods related to Landsat 8 sensor OLI 2018 satellite were prepared and prepared for the necessary pre-processing and processing. Then, using the classification method and applying four plant spectral indices, land use was done in four classes. The investigation of vegetation spectral indices NDVI, NDBI, NDWI and SAVI showed that with the passage of time NDWI and NDVI had a decreasing trend and two indices NDBI and SAVI increased with the passage of time. Kappa index has also been used to evaluate the classification. The results showed that among the four spectral indices under investigation (NDVI, NDBI, NDWI and SAVI), the NDVI spectral index with accuracy percentage of 0.99%, 0.98% and 0.99% during the period from 2014 to 2023, has the highest accuracy in distinguishing vegetation classes. The changes in land use level for each index (NDVI, NDBI, NDWI and SAVI) during the time period from 2014 to 2023 also showed that the highest and lowest levels during this time period are related to NDVI and NDWI index which are equal to 35939.2968 and 541.6227 square kilometers respectively.