One of the most critical features for the successful operation of autonomous UAVs is the ability to make decisions based on the information acquired from their surroundings. Each UAV must be able to make decisions during the flight in order to deal with uncertainties in its system and the environment, and to further act upon the information being received. Such decisions influence the future behavior of the UAV, which is expressed as the path plan. Thus, decision-making in path planning is an enabling technique for deploying autonomous UAVs in real-world applications. This survey provides an overview of existing studies that use aspects of decision-making in path planning, presenting the research strands for Exploration Path Planning and Informative Path Planning, and focusing on characteristics of how data have been modeled and understood. Finally, we highlight the existing challenges for relevant topics in this field.