Environmental situation awareness in this study focuses on monitoring techniques to discover public safety and potential risks at local spots. Changing amount of radiation dose recently has become a great concern by citizen near nuclear power plants. Observation approach to resolution of the concern in this study is the application of Unmanned Aerial Vehicle equipped with a situation monitor in order for covering observation points at the local spots which cannot be accessed by walking or wheeled vehicle. This paper presents an ontology based map integration process that merges 3D trajectory maps into a local distribution map in Google earth. 3D to 2D projection is introduced to visualize changes in spatial situation at ground level by calculation of radiation dose based on distance decay.