Horizontal Accuracy Tests on Google Satellite Images Over Naples Added in QGIS

The chapter delves into the critical evaluation of the horizontal accuracy of Google satellite images over Naples, made accessible through QGIS. It begins by contextualizing the abundance of freely available remotely sensed data and the importance of verifying their positional accuracy for reliable GIS applications. The study focuses on Naples, a city rich in history and cultural significance, and examines the accuracy of Google satellite images using 45 check points distributed across the municipality. The methodological approach is innovative, utilizing vector maps at a detailed scale (1:1,000) to obtain reference coordinates, thereby saving time and resources compared to traditional ground-measured check points. The results reveal an encouraging level of accuracy, with a mean residual of 1.524 meters and an RMSE of 1.594 meters, indicating the potential of these images for various GIS applications and smart city initiatives. The chapter also explores the correlation between positional accuracy and the morphological characteristics of the study area, providing insights into how terrain variability affects the reliability of satellite imagery. The findings underscore the importance of understanding the positional accuracy of freely available satellite data to ensure their effective use in urban planning and smart city development.