The book contributes to the subject area of Remote Sensing and Geographic Information System. It is focused on the study and analysis of automated Cloud detection and removal of satellite imagery using the selection of thresholds value for various spectral tests in the perspective of RSGIS. A significant obstacle of extracting information using satellite imagery is the presence of clouds. Removing these portions of image and then filling in the missing data is an important image editing task. Traditionally the objective is to cut the cloudy portions out from the frame and fill in the gaps with clear patches from similar images taken at different time. Remote sensing are providing opportunities in various branch of environmental research. The fields of application for multi-spectral remote sensing instruments in Earth observation are monitoring the forests, oceans or urban areas over agricultural applications to the extend of natural resources. A significant prerequisite for analysis of Earth observation data is the information that is free from external influences and disturbances. One possible cause of data loss is cloud cover of satellite imagery.