*ISPRS Int. J. Geo-Inf.* **<sup>2023</sup>**, *<sup>12</sup>*, 38 *ISPRS Int. J. Geo-Inf.* **2022**, *<sup>11</sup>*, x FOR PEER REVIEW <sup>7</sup> of 17

**Figure 2.** (**a**) The welcome view of the tested application window with a list of peaks to choose from; (**b**) the view of the selected three-dimensional model of the *Tarnica* peak in the web browser displayed on the PC monitor. **Figure 2.** (**a**) The welcome view of the tested application window with a list of peaks to choose from; (**b**) the view of the selected three-dimensional model of the *Tarnica* peak in the web browser displayed on the PC monitor.

Then, the respondents were asked to watch a video that showed how to use the application in the AR mode (Figure 3). Due to the registration of the real image and of the image displayed on the smartphone screen, functioning in the AR technology, each respondent had an opportunity to see what operating the 3D model looked like and what opportunities to view/operate it in that mode were available (https://youtu.be/E\_t8ZU2OtMY accessed on 29 November 2022). To demonstrate how

In the video, which was the main part of the test survey (Figure 3), the view of the real image, along with the view of the 3D model laid on the real-world view and visible on the smartphone screen, was registered. It was also possible to see the activities performed by the operator. Selected frames of the video are presented in the Figure 3.

the AR mode worked, a Samsung Galaxy S20 smartphone was used.

**Figure 3.** Selected frames from the video attached to the survey questionnaire showing the use of the tested application and activities (**A**–**F**) performed by the operator on a smartphone equipped with the AR mode (https://youtu.be/E\_t8ZU2OtMY accessed on 28 November 2022)—compare with Figure 1a–c. **Figure 3.** Selected frames from the video attached to the survey questionnaire showing the use of the tested application and activities (**A**–**F**) performed by the operator on a smartphone equipped with the AR mode (https://youtu.be/E\_t8ZU2OtMY accessed on 28 November 2022)—compare with Figure 1a–c.

In the first shot from the video (A), one can see the moment of the selection of the *Tarnica* mountain peak (1346 m above sea level). Shot B presents the moment of starting the AR mode in which the mountain peak is going to be displayed. Shot C shows the operator moving the 3D model to place it in the appropriate position on a flat surface. In shot D, one can see how the operator is scaling the model to adjust its size to the one In the video, which was the main part of the test survey (Figure 3), the view of the real image, along with the view of the 3D model laid on the real-world view and visible on the smartphone screen, was registered. It was also possible to see the activities performed by the operator. Selected frames of the video are presented in the Figure 3.

required. Shot E demonstrates that the operator is rotating the model around its own axis. In shot F, one can clearly see that the operator has moved; the model is located in a fixed place that was presented previously, but the operator is looking at the model from a different side of the table, from a different angle and distance. The shot also demonstrates the area visible from the mountain peak (in green) that can be entered by the option "Co widać ze szczytu?" (What can you see from the mountain top?). In the top right corner of the frames (A-E), from the video one can see the same image that is visible on the smartphone screen. The short video was necessary to make it easier for the respondents In the first shot from the video (A), one can see the moment of the selection of the *Tarnica* mountain peak (1346 m above sea level). Shot B presents the moment of starting the AR mode in which the mountain peak is going to be displayed. Shot C shows the operator moving the 3D model to place it in the appropriate position on a flat surface. In shot D, one can see how the operator is scaling the model to adjust its size to the one required. Shot E demonstrates that the operator is rotating the model around its own axis. In shot F, one can clearly see that the operator has moved; the model is located in a fixed place that was presented previously, but the operator is looking at the model from a different side of the table, from a different angle and distance. The shot also demonstrates the area visible from

the mountain peak (in green) that can be entered by the option "Co wida´c ze szczytu?" (What can you see from the mountain top?). In the top right corner of the frames (A–E), from the video one can see the same image that is visible on the smartphone screen. The short video was necessary to make it easier for the respondents to compare both modes available in the application and to help them decide which one (i.e., AR/no and AR) fits a given criterion better (in their opinion).

After watching the video, each respondent would receive six questions concerning their preferences related to the modes of the application compared, i.e., no AR mode (Figure 2b) and AR mode (Figure 3), and suggestions on which one was: *ISPRS Int. J. Geo-Inf.* **2022**, *11*, x FOR PEER REVIEW 10 of 17


In the brackets above, the researchers provided the number of the subsection according to consecutive factors (compare with Figure 4). Respondents had the following qualitative answers: Definitely the AR mode; Rather the AR mode; Comparably AR and no AR mode; Rather no AR mode; Definitely no AR mode; and No opinion. and respectively 9.5% for the 41+ age group). A total of 64.8% of all respondents in the study knew the term AR before and had used AR applications; 10.6% knew the term AR before, but had not used AR apps; 16.2% declared that they did not know the term AR before and had not used AR apps as well; and 8.5% of respondents did not know the term AR, but they had used apps using this technology.

mode (light purple), Definitely no AR mode (dark purple), and No opinion (grey). The black triangles show the dominating answer (if specific modes are indicated, the triangles refer to "Definitely" and "Rather" answers considered jointly). As far as age groups are concerned, there was a visible tendency to give the "No opinion" answer more often by respondents in the 41+ age group. In each case, it was the number reaching one-third of the respondents in a given age group. People from the 19–24 group were more decisive as the percentage of the "No opinion" answer was the lowest in this group. Generally, the

Figure 5 demonstrates the preferences of the respondents that evaluated the two modes of using the application (i.e., AR and without AR), i.e., viewing the 3D model of the exemplary mountain top, *Tarnica*, in terms of which one works best in the context of the analyzed usage traits. The respondents had the following qualitative answers to choose from (Figure 5): Definitely the AR mode (dark blue), Rather the AR mode (light

**4. Results**

### *3.3. Participants*

The study was carried out in the form of an online survey in the group of 142 respondents (72 women, 70 men) of different ages. The youngest participant was 19, the oldest was 83 and the largest number of respondents consisted of people aged 21 (the average age was 32, the median was 28). The respondents were also diverse in terms of social groups; there were students doing majors in Geography-related fields, researchers and people from Klub Zdobywców Korony Gór Polski (Club of the Conquerors of the Crown of Polish Mountains) active in social media. The respondents filled in the survey voluntarily, without any time constraints and gratification, and they could end it at any moment. They were divided into three age groups (19–24; 25–40; 41+), with a similar number of people in each, and with similar percentages in terms of the division into sexes. Figure 4 demonstrates the entire structure of the respondents according to the knowledge of the term "augmented reality" and according to sex, in specific age groups, and overall.

The youngest age group consisted of people aged 19–24. Many of them use a computer and mobile devices not only for studying and working but also for the entertainment, such as computer games, social media and multimedia (e.g., films and music). Another group included people aged 25–40, who remember the "era" before mobile devices with colorful touch screens, and the existence of solutions is not as obvious to them as it is for the younger age group that failed to understand or remember a different state of affairs. The third age group (over 40) consisted of both people who started their adventure with computers when computers were just beginning to come into common use and those who remembered the times when computers and mobile devices had not existed yet or maybe had been in a very early stage of development. Among people aged 19–24, 93% had heard about the term "augmented reality" before they took part in the research; in the group aged 25–40, it was 74.4%; and in the group aged over 40, it was a little bit more than half (52.4%). As much as 94.7% of the youngest respondents used an application that used AR in the past; in the group of people aged 25–40, that percentage was only 74.4%; and in the group aged 41+, the percentage was lower than half (42.9%). There were 50 people who knew the term AR and used such applications in the 19–24 group (87.7% of respondents in this age group), 28 in the 25–40 group (which is 65.1%), and 14 in the 41+ group (respectively 33.3%). When it comes to people that knew the term AR but failed to use such applications, the numbers were the following: 3 in the 19–24 group (5.3% of respondents in this age group), 4 in the 25–40 group (which is 9.3%), and 8 in the 41+ group (respectively 19.0%). There were no people in the 19–24 group that did not know the AR term and failed to use AR applications, in the 25–40 group there were 7 such people (16.3% of respondents in this age group), and in the 41+ group there were 16 such people (which is 38.1%). There were 4 people in each age group that failed to know the AR term but did use such applications (which is 7.0% for the 19–24 age group, 9.3% for the 25–40 age group and respectively 9.5% for the 41+ age group). A total of 64.8% of all respondents in the study knew the term AR before and had used AR applications; 10.6% knew the term AR before, but had not used AR apps; 16.2% declared that they did not know the term AR before and had not used AR apps as well; and 8.5% of respondents did not know the term AR, but they had used apps using this technology.

### **4. Results**

Figure 5 demonstrates the preferences of the respondents that evaluated the two modes of using the application (i.e., AR and without AR), i.e., viewing the 3D model of the exemplary mountain top, *Tarnica*, in terms of which one works best in the context of the analyzed usage traits. The respondents had the following qualitative answers to choose from (Figure 5): Definitely the AR mode (dark blue), Rather the AR mode (light blue), Comparable between the AR mode and the no AR mode (yellow), Rather no AR mode (light purple), Definitely no AR mode (dark purple), and No opinion (grey). The black triangles show the dominating answer (if specific modes are indicated, the triangles refer to "Definitely" and "Rather" answers considered jointly). As far as age groups are concerned,

there was a visible tendency to give the "No opinion" answer more often by respondents in the 41+ age group. In each case, it was the number reaching one-third of the respondents in a given age group. People from the 19–24 group were more decisive as the percentage of the "No opinion" answer was the lowest in this group. Generally, the total result for all age groups and for all criteria showed that the AR mode had more supporters. *ISPRS Int. J. Geo-Inf.* **2022**, *11*, x FOR PEER REVIEW 12 of 17 only 7.7% of the respondents chose the mode without AR. "No opinion" was selected by 15.5% of the respondents.

**Figure 5.** Respondents' preferences regarding the use of the application in the AR mode or non-AR mode, broken down by age group and in total.

In F1, in which respondents were supposed to choose the mode of using the application that was more convenient and with the simpler manner of controlling the 3D model, the polarization was the greatest; the number of answers suggesting that the AR/no AR mode was the better choice was similar in all age groups. In the youngest age group, the no AR mode scored slightly higher (the ratio of with AR/Without AR answers was 0.96), and in the middle (25–40) group the AR mode scored higher (1.1). The AR mode was preferred also in the oldest age group, but it was the "No opinion" answer that actually scored the highest there. The "Comparable between the AR mode and no AR mode" scored the highest in the 19–24 age group. Considering all of the respondents from all age groups, the AR mode seemed to score the highest but only slightly (1.1). The percentage of the respondents who thought that both modes were comparable in that respect was 17.6% and of those who had no opinion 15.5%.

The next subsection (F2) was related to the choice of the more effective mode, i.e., the one that allowed one to take a closer look at the fragment of the model. In that case, in each age group, the mode with AR won significantly. The with AR/without AR ratio was 3.1 for the 19–24 group, 2.1 for the 25–40 group and 2.0 for the 41+ group, respectively. Taking into consideration all answers, the AR mode scored slightly higher than 50% of all answers (29.6% for Definitely the AR mode, 21.2% for Rather the AR mode); for 12.7% of the respondents, both modes were comparable in this respect; slightly more than 20% of the respondents chose Without AR (10.6%—Rather no AR mode, 9.9%—Definitely no AR mode); and 16.2% of the respondents had no opinion. The people that definitely preferred the AR mode came from the youngest age group (38.6% of answers in that group).

As far as F3 is concerned, the respondents were supposed to evaluate which mode was more realistic in terms of the visual perception of the 3D model. In all age groups, there was a strong preference for the AR mode, with a relatively low percentage of "Without AR" answers. In the 19–24 age group, 80% of respondents chose the AR mode; in the 25–40 age group, nearly 60%; and in the 41+ group, it was less than 45%. The last group scored higher in terms of the "Without AR" answer, still reaching less than 15%. Considering all answers from all age groups, the AR mode scored over 60% (35.2% Definitely the AR mode, 26.8% Rather the AR mode), 12.7% of the respondents claimed that both modes were comparable, less than 10% of respondents selected the "Without AR" answer (3.5% Rather no AR mode, 4.9% Definitely no AR mode) and 16.9% of the respondents had no opinion on the matter.

When it comes to F4, according to which respondents decided which mode was the more natural when it comes to viewing the 3D model, it was characteristic that in all age groups answers favoring the absence of AR scored 20%, while in the 41+ group the answer "Definitely no AR mode" was selected more often (16.7%). In the 19–24 group, 63.1% selected the AR mode; in the 25–40, it was 41.8%; and in the 41+, it was 33.3%. In total, 46.8% of the respondents chose the AR mode (23.2%—Definitely the AR mode, 24.6%—Rather the AR mode), 16.9% of respondents believe that both modes were comparable and 19.4% of the respondents chose no AR (10.6%—Rather no AR mode, 8.5%—Definitely no AR mode), with 16.2% of the respondents choosing the "No opinion" answer.

The fifth criterion, according to which respondents selected the more interesting and attractive way of exploring the 3D model, (F5), was dominated by the supporters of AR. It was particularly visible for the 19–24 age group, in which 91.3% of the respondents believed so in total (70.2% chose the "Definitely the AR mode" answer). It was the highest score that was not achieved for any other criterion. At the same time, only 1.8% of the youngest respondents selected no AR for that criterion, and only 5.3% decided that both modes were comparable. In the 25–40 group and 41+ group, a general preference for AR was observed, while there were more "Comparable" and "No opinion" answers. In total, 66.9% of all of the respondents selected AR (46.5%—Definitely the AR mode, 20.4% Rather the AR mode). Both modes were evaluated as comparable by 9.9% of the respondents, and only 7.7% of the respondents chose the mode without AR. "No opinion" was selected by 15.5% of the respondents.

The last criterion, (F6), was related to choosing which mode was better for perceiving and estimating the relative land elevation differences. The distribution of the results looks similar to the one for the fourth criterion. There were many undecisive people in the 41+ age group. In total, 48.6% of the respondents selected the AR mode (28.2%—Definitely the AR mode, 20.4%—Rather the AR mode), 19.7% claimed that both modes seemed comparable to them, 12.6% chose no AR (7.7%—Rather no AR mode, 4.9%—Definitely the AR mode) and 19% of the respondents had no opinion on the matter.

The most unambiguous results were achieved for F5, as the with AR/Without AR ratio was 8.7 in total. This means that the respondents selected AR nearly nine times more often. Particularly, a great part was played by young people, as the number of young people who selected AR was 50 times higher than the number of those who did not select AR. F3 was the second most important criterion. The number of AR supporters was 7.4 times higher than the number of AR opponents. Again, the largest ratio, not as high as for F2, was noted for the 19–24 age group (14.9 times). F6 ranked 3rd. The general ratio was 3.9. F2 and F4 ranked 4th ex aequo. F1 ranked last, with the number of votes distributed nearly evenly, with a slight advantage of AR.

### **5. Discussion**

It seems that, along with the development and popularization of new technologies, devices that handle webXR standards and detection of planes are going to be increasingly available. Currently, the list of such devices includes over 600 models of smartphones of different manufacturers (https://developers.google.com/ar/devices accessed on 29 November 2022) [34]. Among the multiple types of the AR user interface available, such as a backpack computer with HDM, PDA, tablet or AR glasses [35], smartphones are those that seem to be the most available and universal, as we use them for numerous other purposes and have them always at our fingertips.

The AR technology opens up a whole range of new opportunities to interact with digital, 3D models of land relief that may constitute visual aids in learning the topography of specific places. Using webXR standards and algorithms of plane detection allows one to separate a new method of displaying content in AR, i.e., plane-based augmented geovisualizations (PAGs). A PAG frees users from the necessity to be in a specific place to see virtual content, as it frequently happens in augmented reality environments (AREs). Moreover, it is not necessary to use physical objects (paper maps) to start digital content as in augmented map (AM) solutions The tested application, developed for the purposes of this research, constitutes an example of using the PAG method in creating AR solutions. The application makes it possible to display 3D models whenever the mobile device that handles webXR standard detects a plane.

The display of the 3D model on the smartphone screen, combined with the real view of the surroundings (i.e., the room) in which the observation takes place and the plane, on which the model is mounted, makes the entire image more realistic, allowing the user to become immersed in the emerging, partially fictional world. The research shows that the feelings and impressions that were accompanying users during the process of exploring the land relief model seemed to be much closer to reality than when a classic interaction with a 3D model, operated with peripheral devices (a mouse, keyboard or a joystick), takes place. The manner of viewing the model in the AR mode resembles the natural one, because it requires observers to move, change the perspective of looking, change the distance if they want to see the model from a different side or scrutinize a detail that is invisible at a larger distance. At the same time, due to the mobility and flexibility of the solution, users have the freedom to choose the location in which they want to view the model, the scale at which the model is being presented and the initial rotation angle in relation to the observation location.

This research constituted a part of the trend in publications that encourages researchers to examine and establish whether various solutions, such as AR, may be used in practice; whether they may constitute an interesting method of promoting tourism; whether they may be helpful in education (e.g., in teaching geography), specifically, topography [22]; and whether they may be useful in such specific fields as mountain rescue services. As far as education is concerned, Scholz et al. [36] and De Almeida Pereira et al. [19] noted that

the 3D representation of AR can enhance users' abilities to perform spatial positioning and read map data, respectively.

The research on the usability of geomedia is frequently related to homogenous groups, e.g., students [37,38]. What is important in our study, however, was the testing of the usefulness of the AR application among different age groups. The division of respondents into three age groups (19–24; 25–40; 41+) and from different backgrounds became crucial. It seemed legitimate to divide respondents into three age groups because similarities and differences in the preferences related to the factors analyzed (F1–F6) could immediately be observed. Furthermore, significant differences in the subjective preferences of amateurs and experts were noted by Medy ´nska and Zagata [26] for the reconstruction of the stronghold in 3D, as well as by Medy´nska et al. [27] for the complexity level of a people gathering presentation on an animated map.

Those age thresholds were arbitrary, and the respondents may significantly differ in terms of habits, skills, and knowledge of the technology of geovisualizing the geographic space of the mountains, regardless of age. However, the differences obtained seem to prove that the conditions described may be the foundation for adopting such categories for dividing respondents into subgroups.

### **6. Conclusions**

Generally speaking, one may conclude that the AR mode in the application received positive evaluation according to different criteria (F2–F6), which means that respondents, regardless of age, can see the potential of such a solution. In some of the criteria, such as the attractiveness of that way of exploring the 3D model, a significant advantage may be observed; in others, such as easy operation (navigation), the opinions seemed a lot more divided. Quantitative differences were clearly visible in the age groups. One may actually observe certain regularities. It needs to be said that respondents in the 19–24 age group had the most positive opinion concerning presenting the 3D model in the AR mode. In all cases apart from F1, their percentage was over 65%. F1 was the only criterion in which, in that age group, there were slightly more people skeptical concerning AR but that was a statistically irrelevant difference (only 1.7%). It was also the only case in the entire research when the number of supporters of the monitor mode outnumbered the supporters of AR. In the 25–40 age group, the percentage of AR supporters was slightly lower, still reaching over 40% for all criteria, except F1, for which the opinions were almost evenly distributed (roughly 50/50) in all age groups. In the 41 and more age group, AR supporters comprised at least 35% of the respondents for all criteria (except F1). Older respondents (41+ years old) were more reserved towards that way of using the application. Those respondents, much more often than the younger ones, did not have an opinion concerning whether AR worked better for a given criterion. This was most observable for F6 (35.7%) but also for other criteria, where the percentage of indecisive answers was 31–33.3%. There were fewer respondents without an opinion in the 25–40 age group and that percentage was the lowest in the youngest group (the percentage oscillated between 1.8 and 5.3%).

The most unambiguous preferences for using AR for the presentation of the 3D model were observed for criterion F5 (the more interesting and attractive way of exploring the 3D model). F3 (the more realistic when it comes to the visual perception of the 3D model) ranked 2nd. F6 (better at perceiving relative terrain elevation differences) ranked 3rd. F2 (more effective in terms of taking a closer look at the 3D model), and F4 (more natural when it comes to viewing the 3D model) ranked 4th ex aequo. F1 (more convenient and characterized by the simpler way of controlling the 3D model) had an almost equal distribution of votes, with a slight advantage of those for AR.

It is also worth noting that there were some differences in terms of the previous experience with AR within age groups. When it came to the knowledge of the term "augmented reality" and previous experience in using similar applications, those differences were arranged according to age groups: the lower the age of respondents, the higher percentage of AR users or those who knew the term AR prior to participating in this study The higher

the age of respondents, the lower the percentage of such people. Nine respondents from the 41+ age group knew the term AR but had not used similar applications before. In each group there were three respondents that shared the same experience. There were four people in each group that failed to know the term AR but did use AR applications. There was nobody aged 19–24 that used AR applications but failed to know the term. In the 25–40 age group, there were six such respondents, and there were 16 in the 41+ group.

The results show that AR technology that uses the PAG method for creating applications that allow one to view 3D models of land relief fragments is highly useful. They corroborate the fact that this solution may constitute an interesting, willingly chosen alternative to the classic approach to interactive exploration of 3D models on the computer. High scores obtained for specific criteria prove that users have a great interest in this form of geovisualization. The results of the research corroborate the potential of the AR technology and encourage researchers to conduct more studies, extending the range of research by adding the test with the application displayed in AR, with respondents using it physically on their smartphones.

Further research and the development of 3D models of land relief forms in AR may focus on special effects that could be added to the model to make the image even more realistic [39]. On historical topographic maps, the third dimension of the land relief was highlighted by means of suitably applied painterly means of expression [40]. Here, the orthophoto map was the cartographic base and the main objective was to simulate lighting and weather conditions. The opportunities to change the lighting conditions are well known from GIS applications, used for rendering 3D land relief models. Those conditions have a significant impact on the perception of the model [41]. It seems that, in this situation, smart solutions should adjust the height of the source of lighting, as well as the direction of lighting and length of the shadow cast to the position of the observer in relation to cardinal directions, the season, the time of the day and the real lighting conditions that may occur in a given location as a result of all those factors [42–44]. Furthermore, adding mist, as it takes place in the online 3D atlas of Switzerland (www.atlasderschweiz.ch accessed on 29 November 2022) [45,46], as well as rain, snow and clouds (as in 3D cities or in the digital land relief model in the TerrainView application), could create a highly interesting effect.

**Author Contributions:** Conceptualization, Ł.H. and Ł.W.; methodology, Ł.H. and Ł.W.; software, Ł.H.; validation, Ł.H.; formal analysis, Ł.W.; investigation, Ł.H. and Ł.W.; resources, Ł.H.; data curation, Ł.W.; writing—original draft preparation, Ł.H.; writing—review and editing, Ł.W.; visualization, Ł.H.; supervision, not applicable; project administration, Ł.H.; funding acquisition, not applicable. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare no conflict of interest.

### **References**


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