## 2 Materials and Methods
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Geospatial technique** & **Description** & **Maturity Level** & **Ref.** \\ \hline GIS & **GIS** is a computer system that collects, stores, manages, analyzes, displays, and applies geographic information, as well as a general technique for analyzing and managing mass spatial data. & [41] \\ \hline Remote sensing & **Remote sensing** refers to the acquisition of information on a given target without making contact with the target. It uses the entire electromagnetic spectrum, ranging from short wavelengths (for example, ultraviolet) to long wavelengths (microwaves). & \\ \hline Topographic survey & **Topographic surveys** are generally used for the representation of the Earth’s undulating topography, commonly known as relief features of the Earth’s surface. & [43] \\ \hline Photogrammetry & **Photogrammetry** provides the ability to build three-dimensional (3D) models from two-dimensional (2D) images. & [44] \\ \hline Computational vision (CV) & **CV** is a broad term mainly used to refer to processing image and video data. CV aims to enable machines to perceive, observe, and understand the physical world as if they have human eyes. & Emerging & [45] \\ \hline Real-time monitoring or Internet of Things (IoT) (Absolute or relative coordinates) & **Real-time monitoring and IoT** allow real-time data collection, contributing to more proactive planning and early detection of issues before they cause unplanned downtime and revenue loss. Whenever georeferenced data is considered either by absolute coordinates (latitude/longitude by Global Position System (GPS)) or relative coordinates (distance to a reference point). & Experimental & [47] \\ \hline Geo-visualization & **Geo-visualization** techniques developed are able to provide information about the different spatial data for users in a visual way and also help to understand better the spatial information using a cognitive approach. & [48] \\ \hline Geophysics & **Geophysics** analyzes the distribution of physical properties in the subsurface for a wide range of geological, engineering, and environmental applications at different scales. Seismic, electrical, magnetic, and electromagnetic methods are among the most applied and well-established geophysical techniques. & [49] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Description of the main geospatial techniques included in the systematic review. * **HVC:** TITLE-ABS-KEY. (\"production\" OR \"storage\" OR \"fuel cell\" OR \"end-users\" OR \"transport\" OR \"cross-cutting\" OR \"Supply Chain\" OR \"Value Chain\" OR \"Infrastructure\" OR \"mobility\" OR \"use\"). To ensure that the results are complete, different synonyms such as \"hydrogen\" OR \"green hydrogen\" OR \"renewable hydrogen\" OR \"Hydrogen Economy\" have been used. To ensure that the research is replicable and updatable as the field evolves, this study follows the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) methodology [49]. Figure 1 presents the flowchart outlining the selection and refinement process of the research included in the systematic literature review. An initial total of 3632 documents (SCOPUS: 1946 and WoS: 1686) were retrieved based on the search terms without applying restrictions. To align with the scope of this review, which focuses on recent developments, the dataset was limited to publications from 2019 to 2025. This refinement reduced the number of relevant documents to 2188 (SCOPUS: 1182 and WoS: 1006). This initial filtering step reveals that over 60% of the research utilizing  
Figure 1: Refinement of studies based on the PRISMA workflow. geospatial techniques in the hydrogen value chain (HVC) has been published within the last six years, underscoring both the novelty and the growing importance of the topic. Papers indexed as \"Book Chapter\", \"Original review\", 'Article' and \"Conference Paper\" and using English as language were considered. Therefore, 658 documents were excluded from the initial identification (SCOPUS: 265 and WoS: 393).