Any study of urban-rural relations and interactions requires the fundamental assumption that some spaces can be classified as “urban” and others as “rural”. While this is true, urban and rural areas do not constitute two separate territories that can be needed in isolation. On the contrary, they are surely interrelated in many ways, and their connections must be investigated, theoretically and empirically, in terms of identity, causality, and effects.

Terms like  rural  vs.  urban  and  rural  vs.  the city  are commonly used to identify the main types of geographical spaces, both in academic and colloquial circles. Defining them, in both cases frequently, implies a simplifying conceptual approach to address interdependent and complementary realities, focusing on the main characteristics of their interconnections; hence the numerous and continuous attempts to derive an almost impossible conceptual delimitation that, until recently, and especially in the case of rural spaces, frequently lacked exhaustiveness and precision [ 1 , 2 ].

The terms "rural" and "urban" refer to spatial realities that have often been interpreted as opposed, or even antagonistic and divergent [ 10 , 11 ], from a dichotomous binary perspective based on alterity with the urban environment. This approach not only represents a simplification in various aspects, but also expresses a non-existent homogeneity of rural and urban spaces, as if there were only one model of each category.

Spatial reality is much more complex than the previous notion. Furthermore, this issue of complexity is increasing and a full understanding of the need for multiple interdisciplinary analyses. This is especially true today, when hybrid spatial environments [ 12 ] and numerous multifunctional rural landscapes [ 13 ] are being configured. Although the most intense interactions are taking place in rural spaces that have been integrated into functional urban and peri-urban areas, rural spaces that are more distant or less connected to urban ones are also experiencing the impact of cities, albeit indirectly; for example, as the drop in population levels caused by rural-urban migration [ 14 ].

Regarding the first aspect, many rural areas are now witnessing the birth of a differentiated spatial reality. The term “new rurality” [ 15 , 16 , 17 , 18 ] refers to the reconstructed forms of organization and the functional transformations that are being observed in spaces that previously had a rural identity and that are now evolving towards a different category of rural space. [ 19 , 20 ]. Although the meanings assigned to this term by different theorists do not always coincide, in particular, there are significant conceptual differences between European [ 21 ] and Latin American [ 22 ] authors., 23 , 24 , 25 , 26 , 27 , 28 ]—, it is generally accepted that the essential features of this “new rurality” consist of a greater mobility of people and merchandise, the diversification of economic activities and a modification of the use of the land. soil [ 29 , 30 ].

A major socioeconomic transformation that has taken place in many areas is “deagrarianization” [ 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38], that is, the reduction in the importance of agricultural activities, in terms of employed population and income, and the corresponding greater weight of non-agricultural forms of employment. The degrarization leads to a progressive loss of traditional ways of life, so that agricultural activity ceases to constitute the economic base and the main hallmark of rurality. It is a process that responds to the new productive and territorial logics of the globalized economy and that has been associated with deruralization [ 39 ] from a perspective based on the premise—that the rural environment can be fully identified with agricultural activity. As far as Spain is concerned, deagrarianization [ 40 , 41 , 42] has been cited among the structural causes of the rural exodus, with special reference to the modernization of agricultural activity [ 43 ]. For this reason, it is often seen as a generalized effect and not exclusive to urbanized rural areas.

Another significant change, generally complementary to the previous one, is the shift in patterns of employment and economic activity towards the service sector, together with the acquisition of a subsidiary residential function with the construction of second homes for the urban population [ 44 , 45 , 46 ].

The historical interaction between rural and urban spaces has been constantly evolving, profoundly transforming the relationships between the countryside and the city [ 47 ] and blurring the boundaries between urban and rural environments. However, significant differences persist and few authors question the existence of a rural-urban gap. Furthermore, scholars have observed the gradual consolidation of fissures between different types of rural spaces [ 48 , 49 , 50 ], although these may be masked by the regular occupational mobility of a large part of the rural population [ 51 , 52 ].

It is almost universally recognized that the main driver of these changes is 'rural urbanization'. This process has multiple consequences, including the physical modification of the territory and changes in its socioeconomic structures [ 53 , 54 , 55 ]. This urbanization is functional, morphological, landscape and cultural, and occurs not only in areas bordering or with easy access to large cities, but also in more remote areas bordering medium-sized and even small cities [ 56 , 57 , 58 ] , thus configuring micropolitan areas [ 59 ].

The fact that urbanization processes are the main factor triggering the territorial mutations that have occurred in many contemporary societies [ 60 , 61 , 62 ] explains the primacy of the urban-centric approach that has been adopted in most studies. about rural areas, both past and past. present [ 63 , 64 ]. Thus, it is widely accepted that the revitalization of rural spaces goes through logics according to which they are physically and socially modified. These logics also have an impact on the strategies used to obtain the economies of urban agglomeration, such as spatial externalities, from which some rural areas also benefit [65 , 66 , 67 , 68 , 69 , 70 ]. Conversely, other spaces, typically those in peripheral and marginal locations, may suffer from the adverse effects of reflux, a process associated with the core-periphery paradigm [ 71 , 72 , 73 , 74 , 75 , 76 , 77 , 78 , 79 , 80 , 81 ].

The urbancentric notion is also related to numerous concepts and words that have been coined to define the changing relationships between rural and urban settings: “suburbanization” [ 82 , 83 ], “periurbanization” [ 84 , 85 ], “rurbanization” [ 86 , 87 , 88 ], “exurbanization” [ 89 ], “rural urbanity” [ 90 ], “rural gentrification” [ 91 , 92 , 93 ], “urban countryside”, “infiltration of the city into the countryside” [ 94], etc. Furthermore, some of these terms are closely related to a process that has been called “counter-urbanization” [ 95 , 96 , 97 , 98 ]. The proliferation of recent studies that address these concepts highlights their conceptual interest and underlines the presence of a renewed dialogue between rural and urban geographies.

Another relevant consideration is the territorial concept of sprawltown [ 99 , 100 , 101 ], also identified as “ città diffusa, campagna urbanizzata ” [ 102 , 103 , 104 , 105 , 106 , 107 , 108 , 109 , 110 ], characterized by the absence of vertical territorial hierarchies from the center to the periphery, which are replaced by horizontal connections between population centers and by the dispersion of functions [ 111 , 112 ].

It is now widely accepted that the old elements of differentiation between urban and rural contexts are no longer operational and that alternative approaches to spatial realities are required. One of these approaches involves the functional integration of the two types of geographic spaces, whose hallmarks, such as agricultural activities, are weakening but have not completely disappeared [ 113 ]. One result of these changes is the creation of multifunctional spaces and hybrid landscapes [ 114 , 115 , 116 ], ambiguous spaces in which urban and rural features fade or even disappear as clearly legible spatial units within the landscape [ 117, 118 , 119 ].

Recent studies on these issues have adopted a more fully integrated perspective of geographic space, moving beyond the dichotomous viewpoint, which many believe reflects an anachronistic static perspective [ 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 , 128 , 129 , 130 , 131 , 132 ].

Geographic space has long been viewed and analyzed as a continuum, containing a gradual transition from urban to rural and vice versa, without noticeable territorial discontinuities [ 133 ]. However, this interpretation has been questioned by some authors [ 134 ] and updated and reformulated by others [ 135 , 136 , 137 ]. However, for most experts, the concept of spatial continuum is accepted as a gradient of urban/rural levels [ 138 ] or as cyclical phases of urbanization [ 139 ].

Some authors even deny the usefulness of the traditional terminology for different types of spaces (suburban, peri-urban and rururban), affirming that what has been configured is a new model of a detached city that is post-industrial or even post-urban [ 140 , 141 , 142 , 143 , 144 , 145 ], which should be understood as an integrated mosaic of urban elements within a territorial matrix [ 146 ] as a result of a “metastatic metropoliticization” [ 147 , 148 , 149 ].

The question of how rural areas and zoning interrelate has attracted increasing interest since the late 20th century [ 150 ], with increasing studies influencing socio-economic and land-use planning policies. for rural areas and lead to the adoption of new paradigmatic and methodological approaches. This new point of view could be seen as a "rejuvenation" of rural geographic studies, based on a scientific and epistemological renewal achieved through dialogue and debate between rural and urban researchers seeking to improve our understanding of developments in this area[ 151]. Although the contemporary approach to rural geography maintains some classic criteria, it also reveals new perspectives and is increasingly interested in the diverse practices and representations of the rural environment and its inhabitants [ 152 , 153 , 154 ].

This evolving research focus first became apparent in the United States and Europe [ 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 ] and later in Latin America [ 172 , 173 , 174 , 175 , 176 ,177 , 178 , 179 ], and is currently being accepted in Asia, especially China [ 180 , 181 , 182 , 183 ]. In the latter country, after the accelerated urbanization of the countryside under the model of state capitalism applied in China since the end of the 1970s [ 184 ], there have been drastic changes in land use, with a large-scale conversion of agrarian to urban practices. This development has attracted the attention of numerous researchers from different areas of knowledge, including geography, economics, and environmental sciences [ 185 , 186 , 187, 188 , 189 , 190 ].

Numerous recent studies have analyzed and interpreted the functional territories [ 191 ] resulting from rural-urban integration or hybridization [ 192 , 193 , 194 , 195 ] in the so-called “rural-urban fringe”, understood as a space with its own characteristic character. [ 196 , 197 ]. This entity has also been described as the “rural-urban interface” and as composed of urbanized rural areas, intermediate territories, intermediate territories (TiBs), the territories of a new modernity [ 198 , 199 ] or “hybrid geographies”.

Most studies on these issues have focused on the territorial transformations derived from economic and technical changes (degrarization and outsourcing, in particular) in the distribution of services and production centers, in physical and virtual accessibility and, especially, in mobility [ 200 ].

On the other hand, some recent analyzes of rurality and urbanity [ 201 , 202 ] continue to address quantifiable data such as population size [ 203 , 204 , 205 , 206 , 207 ], population density and/or distances between settlements of different categories [203, 204, 205, 206, 207] 208 , 209 ]. However, these indicators are relatively ineffective as a means of describing rurality [ 210 , 211 , 212], including multivariates that incorporate not only population density but also factors such as demographic dynamics, mobility patterns, migrations, and distances to major service centers [ 213 , 214 , 215 , 216 , 217 ]. Very few analyzes have also used geographic information techniques for territorial measurement [ 218 , 219 ].

It has been observed that the effects of the urbanization of rural spaces must be considered according to the specific conditions of both rural and urban spaces in which the process takes place [ 220 ]. The reason for this is that the dynamics of urbanization do not occur in the same way or with the same intensity in all territories. In recent times, both the variety and the complexity of rural spaces have intensified; some evolve dynamically, while others are characterized by stagnation and decline.