Extended Abstract
Introduction
Due to the increasing growth of urbanization, the exponential expansion of cities, and the severity of environmental, social, and psychological issues. Currently, the issue of planning for leisure time and developing and equipping recreational spaces on urban and suburban scales has become a social necessity; recreation in natural areas can take many of us away from daily life and the nervous pressure of the city streets. Like many urban centers, the Mashhad metropolis has faced a rapid urban growth trend in recent years. On the other hand, the existence of the Holy Shrine of Imam Reza, as a religious center for Shia Muslims in the Islamic world and influenced by other religious, historical, social, and economic values, has caused a large number of pilgrims and tourists from cities and surrounding countries to travel to this city. Therefore, this city needs special attention to strengthen and create attractive and functional public spaces to improve the mental health of the urban community and enhance its position in urban competitions, considering the transnational role of this city. The southern heights are one of the most important natural landscapes in the urban landscape of Mashhad, which has enhanced the overall ecological image of the city. On the other hand, some actions in the process of equipping the environment for the development of recreational activities have caused unreasonable interference and conflicts in the natural areas around Mashhad, especially in the southern highlands, which currently show the rapid process of changes in the visual-perceptual system of the environment. Thus, the current research, aimed at "evaluating the visual effects of the southern highlands using a development approach with the role of a resort," tries to understand the visual values of the environment in the development of the area under study with the function of a resort to strengthen the relationship between humans and the natural environment and identify the negative effects of development on visual resources. The results can help target the development of the mentioned area as an attractive urban space accessible to the public while paying attention to the protection of ecological qualities in the design and operation process.
 
Methodology
Based on library and documentary studies, a framework of theoretical foundations was developed in the initial stages of this research. In this section, using a questionnaire, criteria extracted from review studies to evaluate the effects of landscapes were checked and weighted by 15 specialists and experts in this field. In the next step, relying on field methods to record the scenery and the focal points of the scenery to simulate the scenery resulting from the resort development projects in the studied area in order to evaluate the visual effects of development measures and policies on the existing visual resources, public preferences from tourists and experts were received using questionnaire tools and images of simulated landscapes. This process randomly selected 15 experts and 165 tourists as the statistical population. Finally, the data analysis was performed based on the data obtained from comparing the existing landscapes and the landscapes caused by the development. In the final part, solutions were presented based on reducing the negative visual effects caused by the development measures.
 
Results and discussion
According to the results, in general, the development measures of the promenade in the southern heights of Mashhad have affected many linear and wide corridors due to the establishment of artificial elements (such as service buildings, gazebos, facility elements, benches, etc.) or the planting of trees in a non-targeted manner. Moreover, vision is often limited to distant visual qualities, especially when receiving wide landscapes. Although the planting of trees has improved the sense of naturalness and complexity in most of the received landscapes, on the other hand, due to the lack of attention to the effects of planting trees on the sight corridors, in many views of this area, the range of vision is limited, and the distance of receiving the view is reduced in people's perception. Additionally, the presence of artificial elements incompatible with the natural form of the area has caused a sense of inconsistency and reduced cohesion in the natural integrity of the landscape. Furthermore, the traffic of cars and heavy vehicles, along with the presence of artificial elements incompatible with the natural form of the area, has reduced the sense of naturalness, virginity, and untouchedness. Consequently, it has reduced the visual and ecological qualities of the audience of this area, including mountaineers and nature walkers.
 
Conclusion
In this area, there needs to be a focus on following a set of measures to develop and equip the southern elevations of Mashhad metropolis. However, these measures should consider the effects on the image and natural landscape of the area, as well as the visual corridors towards natural visual resources, particularly strategic centers offering wide views of the city with high visual quality. Visibility is limited, and artificial environmental elements reduce the sense of naturalness in many landscapes. By examining research sources based on landscape assessment methods, it becomes evident that more activity needs to be undertaken in this area. However, it is noteworthy that despite the attention of city managers from other cities in the country towards the development of the resort in the southern heights of Mashhad as a valuable project, no research has been conducted focusing on the visual effects of this area. Thus, the results obtained from the present research can contribute to the improvement of the management of the valuable visual resources of this natural area in the recreational development process. It can also be used as an experience in evaluating the visual effects of the recreational development of similar projects.
 
Funding
There is no funding support.
 
Authors’ Contribution
Authors contributed equally to the conceptualization and writing of the article. All of the authors approved the content of the manuscript and agreed on all aspects of the work declaration of competing interest none.
 
Conflict of Interest
Authors declared no conflict of interest.
 
Acknowledgments
 We are grateful to all the scientific consultants of this paper.