The potential of GIS and multi-platform remote sensing for dynamic landfill airspace monitoring: A systematic review of trends, applications and opportunities

Abstract Efficient landfill airspace management is a critical aspect to address the growing global waste crisis. Waste facility operators are encouraged to limit landfilling by focusing on waste recovery and recycling efforts. Reliable monitoring tools became essential to achieve desirable decisions for optimal landfill airspace usage. This systematic review presents the findings on employing geographic information system (GIS) and remote sensing (RS) in landfill airspace management, while also exploring their potential applications in assessing landfill settlement. The literature in this field has expanded at an average annual rate of approximately 26.3%. Nearly half of the studies reviewed (43%) originated from China, the USA, and Italy. Contributions from other countries remain limited, suggesting that research in this area is still emerging globally and has not yet achieved widespread adoption.The primary research approach identified was through the use of airborne and spaceborne RS, accounting for 70% of the total studies. This was followed equally by geotechnical/in-situ monitoring, mathematical modelling, and review-based synthesis. The review findings clearly indicate that airborne RS, mainly through Unmanned Aerial Vehicles (UAVs), have emerged as the key technology for volumetric monitoring of landfill airspace, surpassing traditional ground-based surveying techniques. However, it is noted that future studies on landfill airspace management should adopt context-driven approach to ensure that the selection of GIS and RS tools is well-aligned with the specific objectives and requirements of each study. This study further highlights that integrating GIS and RS technologies can generate reliable datasets, enhance the accuracy of landfill settlement models and optimize the data collection process. Settlement parameters that can be effectively monitored using these tools are landfill elevation, waste volume, gas emissions, moisture distribution, and thermal behaviour. To further develop landfill airspace and settlement assessment through the integrated GIS-RS approach, it is essential to address data collection limitations for various landfill parameters, ensure the accuracy and reliability of data and equipment, and enhance funding support, technical expertise, and knowledge in the field.