## 5 Conclusions
In this regard, in the short term, it is considered that they should focus on overcoming the main barriers identified in relation to optimal site selection, monitoring and safety, and social acceptance. Although GIS, employed in roughly 80% of the papers for site selection and local resource assessment, has been identified as the predominant geospatial technique, the study has shown that other geospatial techniques such as photogrammetry and CV offer promising applications, including component inspection, infrastructure monitoring, and leak detection, but their use in the hydrogen sector remains limited. This is likely due to a combination of factors: technical difficulties in applying them in outdoor or industrial environments, high equipment and processing costs, and a physical infrastructure (production facilities, pipelines, applications) that is still limited. As the sector matures and the hydrogen industry grows, these techniques are expected to be adopted more widely, especially in process monitoring and automation. Based on the analysis of recent trends in each of the stages of HVC, the following three priority lines of research are proposed, which are undertaken in the next five years:  
* **GIS, IoT, and satellite information-based computational geo-intelligence framework. ** The development of tools capable of integrating real-time information on renewable energy resources from different sources of information is recommended. One of the key features of this type of tool is that human-machine interaction must be reduced, integrating predictive and machine learning models to automate the decision-making process at the local level. A framework of this kind would be very useful for administrations responsible for energy planning or for those responsible for the sustainability of critical facilities such as airports or ports. * **Participatory co-creation tools in early hydrogen application projects. ** The aim is to involve the different stakeholders in the development and evaluation of the functioning of a hydrogen-based energy community or hydrogen valley. It is considered that to increase social acceptance, it is necessary to have traceable (geolocated) tools where aspects for improvement and opinions from real users can be integrated. In this case, a combination of GIS and blockchain could be useful to promote end users' confidence in this technology, as well as being a useful source of information for professionals in the sector. * **Geospatial DT framework with real-time monitoring of facilities. ** Having DTs of facilities in operation is key to efficient management, improved safety, and the training of new professionals. In the process of creating DT, technologies such as LiDAR or photogrammetry will be useful for creating the 3D model, while techniques such as IoT or IRT will be useful in the operational phase for managing and monitoring the safety of the facility. Finally, we acknowledge that this review is limited to English-language literature indexed in Scopus and Web of Science through 2025; rapidly evolving practices and non-indexed studies may offer additional insights beyond this scope. **Author Contributions:** Conceptualization, G.H.-H. and N.V.-A. ; methodology, N.V.-A. ; validation, G.H.-H., N.V.-A., S.D.P. and S.L. ; formal analysis, G.H.-H., N.V.-A., S.D.P. and S.L. ; investigation, G.H.-H., N.V.-A., S.D.P. and S.L. ; resources, G.H.-H., N.V.-A., S.D.P. and S.L. ; writing--original draft preparation, G.H.-H., N.V.-A., S.D.P. and S.L. ; writing--review and editing, G.H.-H., N.V.-A., S.D.P. and S.L. ; project administration, S.D.P. and S.L. ; funding acquisition, S.D.P. and S.L. All authors have read and agreed to the published version of the manuscript. **Funding:** This research was funded by Spanish Ministry of Science and Innovation for the economic support given through NEXGENERATION EU funds under project HYSTORENEW (funded by CDTI in CIEN program). The authors also like to thank the SUDOE Interreg Program for the economic support given through SHAREDH2-SUDOE project.