###### Abstract
(**a**) (Reprinted from [7] with permission from [PERSON]/GNUplot); (**b**) (Reprinted from [8] with permission from [PERSON]). ever, maps do not currently meet these standards. In fact, the European Directive on the accessibility of websites and mobile applications offered by the public sector [12] states explicitly, \"Article 1.3. This Directive does not apply to the following websites and mobile applications:... (d) online maps and mapping services, as long as essential information is provided in an accessible digital manner for maps intended for navigational use.\" We can also find this translated in other national directives [13]. Nevertheless, the battle is not lost, and we can point to research that evaluated existing limitations and proposed how to overcome them [14; 15; 16; 17; 18; 19]. One way to circumvent these access limitations is through other types of interfaces, such as VUIs. Of note, the field of accessibility is not limited to applications for disabilities but covers the entire population spectrum. Integrative orientations, such as Design for All, Universal Design, or Inclusive Design, emphasize that accessibility problems can arise from not only circumstances at birth but also age, illness, trauma, life changes [20; 21; 22], or the education level [23]. In line with this, the more recent term \"place-on\" [24] (based on the widely known concept of personas [25]) shows how the user's location and activity influence their choice of technology (and, therefore, acceptance). For example, in the car, the place-ona is \"eyes busy, hands busy, ears free, voice free\"; in the kitchen, it is \"hands busy, eyes, ears and voice free\" [26]. Furthermore, in the changing technological context illustrated before, designing smart products entails not only the definition of technologies, services, components, and communication processes but also the consideration of new relationships of understanding, using, and interacting between humans and technology [3; 22; 27]. In this line and according to user-centered design philosophies, understanding user needs and behavior is essential [28; 29]. As [22] stated, we should identify the problems users face, view them from their perspective, develop a critical view of the need to define related product functionalities, and humanize the software we create. Nonetheless, an outstanding issue is establishing effective interaction with the user. For example, the Loopventures test in [30] highlighted this point by assessing the gap between success in understanding (i.e., the extent to which the assistant correctly registers the user's words), which is close to 100%, and success in executing the appropriate response to the user's needs (i.e., whether the response provided is correct). The resulting gap ranged from 52.4% to 85.5%. In other words, a gap exists between the effectiveness of grammar (which works properly) and the establishment of prompts (which fail in many cases). However, even the first level of success has not been achieved for GISs since a corpus of natural language terms is not available that allows the usual functions of a GIS to be commanded. This paper develops technology elements to gain knowledge of how we can expand VUIs for GISs. This expansion might empower virtual assistants with advanced capabilities so they can deliver more advanced GIS services. A voice-based approach, in particular, may offer tools to improve these systems' accessibility. The work focuses on managing the interaction with a web-based user interface that can correspond with Google Maps and other geographic information visualization tools offered by spatial data infrastructures [31]. Despite having many general elements, such as voice recognition libraries, the current technology still lacks the ability to fully understand and process the semantics that real users apply to command the geographic information systems. This paper presents a three-part study assessing and improving VUIs for Spanish speaking users, which follows a mixed-methods approach [32].