# RECORD 755578f10943061d8e5adfd02909b14166725d76 # TITLE: Influence of the Urban Green Spaces of Seville (Spain) on Housing Prices through the Hedonic Assessment Methodology and Geospatial Analysis # YEAR: 2022.0 VENUE: Sustainability DOI: 10.3390/su142416613 # AUTHORS: E. Ramírez-Juidías; J. Amaro-Mellado; J. Leiva-Piedra # PAGES: 15 CANDIDATE TABLE PAGES (1-based): [8, 9] # ABSTRACT: The city of Seville (Spain) is made up of a historical network of pre-existing city overlaps, which increase the economic and heritage value of certain urban areas. To date, green spaces are one of the most important variables in determining the economic value of housing. Thus, this paper uses the hedonic technique and geostatistical analysis with GIS as a methodological approach to infer the economic influence of urban green spaces on housing prices. Along with the traditional variables used to explain dwelling prices, the size of the green space has also been taken into account as an environmental variable affecting prices. The sample consists of 1000 observations collected from Seville. According to the findings, the most relevant variables depend on the hedonic model. Still, in general terms, a dwelling’s selling price is related to basic explanatory variables such as living area, number of rooms, age, and number of baths. The green area per inhabitant present in a dwelling’s district is also included as part of these basic explanatory variables. In conclusion, the hedonic linear model is the model that best fits housing prices where the values are similar to those obtained by kriging regardless of the district. Based on this research, each square meter of green space per inhabitant in a district raises the housing value by 120.19 €/m2. ===== PAGE 1 (score 20, numeric-paren 0, table-words 1, var-words 18) ===== Citation: Ramírez-Juidías, E.; Amaro-Mellado, J.-L.; Leiva-Piedra, J.L. Influence of the Urban Green Spaces of Seville (Spain) on Housing Prices through the Hedonic Assessment Methodology and Geospatial Analysis. Sustainability 2022, 14, 16613. https://doi.org/ 10.3390/su142416613 Academic Editors: Marco Devecchi, Fabrizio Aimar and Matteo Caser Received: 6 November 2022 Accepted: 9 December 2022 Published: 12 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). sustainability Article Influence of the Urban Green Spaces of Seville (Spain) on Housing Prices through the Hedonic Assessment Methodology and Geospatial Analysis Emilio Ramírez-Juidías 1 , José-Lázaro Amaro-Mellado 2,3,* and Jorge Luis Leiva-Piedra 4 1 Instituto Universitario de Arquitectura y Ciencias de la Construcción (IUACC), Universidad de Sevilla, 2 Reina Mercedes Avenue, 41012 Seville, Spain 2 Departamento de Ingeniería Gráfica, Universidad de Sevilla, 41092 Seville, Spain 3 Instituto Geográfico Nacional-Servicio Regional en Andalucía, 41013 Seville, Spain 4 Laboratorio de Investigación en Teledetección, Universidad Tecnológica del Perú, Intersección Avenida El Progreso s/n-Vía de Evitamiento, Chiclayo 14001, Peru * Correspondence: jamaro@us.es Abstract: The city of Seville (Spain) is made up of a historical network of pre-existing city overlaps, which increase the economic and heritage value of certain urban areas. To date, green spaces are one of the most important variables in determining the economic value of housing. Thus, this paper uses the hedonic technique and geostatistical analysis with GIS as a methodological approach to infer the economic influence of urban green spaces on housing prices. Along with the traditional variables used to explain dwelling prices, the size of the green space has also been taken into account as an environmental variable affecting prices. The sample consists of 1000 observations collected from Seville. According to the findings, the most relevant variables depend on the hedonic model. Still, in general terms, a dwelling’s selling price is related to basic explanatory variables such as living area, number of rooms, age, and number of baths. The green area per inhabitant present in a dwelling’s district is also included as part of these basic explanatory variables. In conclusion, the hedonic linear model is the model that best fits housing prices where the values are similar to those obtained by kriging regardless of the district. Based on this research, each square meter of green space per inhabitant in a district raises the housing value by 120.19 €/m2. Keywords: hedonic method; GIS; geospatial analysis; urban green space; housing prices 1. Introduction Green spaces serve essential environmental and recreational functions [1]. Forest and urban vegetation, in edaphoclimatic terms, improve the environment in which they are found and serve as the foundation for the conservation of fauna and flora. Recreational activities with a basis in nature are becoming more popular and, while the effects are on a smaller scale, urban parks serve the same environmental and recreational functions as larger forests and green spaces. Gardens and city parks play the primary environmental function of absorbing carbon dioxide (CO2) emissions. These emissions are primarily generated through the use of private vehicles in urban transportation. Moreover, emissions have increased significantly in recent decades. It is worth noting that, in Spain, each person in a large city emits 4.62 tonnes of CO2 per year [2]. Given that one hectare of Mediterranean forest can absorb approximately four tonnes of CO2 per year, a simple calculation leads us to conclude that we require more than one hectare of green space per inhabitant (inh) to offset the pollution generated by these emissions. The preservation of urban green spaces is thereby becoming increasingly important in order to combat the growing contamination of our cities. Additional factors, such as acoustic isolation, should be included in the list of the environmental functions of urban green parks as some gardens serve as acoustic screens Sustainability 2022, 14, 16613. https://doi.org/10.3390/su142416613 https://www.mdpi.com/journal/sustainability ===== PAGE 8 (score 27, numeric-paren 0, table-words 7, var-words 9) ===== Sustainability 2022, 14, 16613 8 of 15 the average price per m2 and was taken into account (Table 4) in accordance with Solano- Sánchez et al. [39]. Under the predefined hypothesis, a higher value per m2 in a district implies a higher dwelling value. This index was created by assigning one value to the city’s most expensive district and then assigning a proportional value to the remaining zones. In order to be able to test and validate this study, a comparison of real price (www.idealista.com) versus estimated price for each HPM model will be conducted. Table 4. District Index (DI) value for each set of districts (Own elaboration). Set of Districts €/m2 DI Triana 2715.69 0.865 Torreblanca-Sevilla Este-Parque Alcosa 1207.94 0.385 Santa Justa-Miraflores-Cruz Roja-San Pablo-Santa Justa 1919.3 0.612 San Jerónimo-Pino Montano 1188.24 0.379 Prado de San Sebastián-Felipe II-Bueno Monrreal-La Palmera-Los Bermejales-Bellavista-Jardines de Hércules 2497.18 0.796 Nervión 2642.49 0.842 Macarena 1368.73 0.436 Los Remedios 2899.17 0.924 Cerro-Amate 1017.51 0.324 Centro 3137.89 1 Finally, a literature review was conducted to analyze the results obtained in this study and to carry out a coherent discussion concerning the works published to date. 5. Results and Discussion Following the data analysis, it was discovered that including the green area (m2/inh) variable in the price equation allowed for the estimation of the influence of environmental factors on dwelling market value. In order to find out if the HPM presents multicollinearity, it was decided that obtaining the Variance Inflation Factor (VIF) (Table 5) would be required. As is well known, if the VIF value for each independent variable is greater than ten then the multicollinearity is considered to be high. Table 5. Independent variables and coefficients of linear HPM model (r = 0.85, R2 = 0.721, p ≤0.001) (Own elaboration). Variables Coefficients Stand. Error Student’s t Prob. VIF Constant −120.443 14.795 −0.075 0.000 - Size (m2) 30.032 0.039 1.7 0.000 1.622 Baths (n◦) 98.725 0.042 0.14 0.000 1.467 Age (years) −53.31 1.42 −1.42 0.000 1.535 Green area (m2/inh) 11.145 0.87 0.872 0.000 1.020 Regarding the HPM model selected as the most satisfactory, it should be mentioned that the linear function form was found to be the most appropriate after performing the data analysis. Like the VIF, Table 4 also displays the independent variables’ coefficients. As for the logarithmic model, in addition to the VIF value, Table 6 provides the differences with respect to the linear model. Thus, the main difference is the dependence on the number of rooms (Rooms) variable in the logarithmic model. In contrast, under the linear model, the property’s value depends on the dwelling area (Size) variable. This may be because of the relationship between both variables which causes the predominant variable to cancel the slave variable in the requisite model depending on the selected model. ===== PAGE 9 (score 17, numeric-paren 0, table-words 4, var-words 6) ===== Sustainability 2022, 14, 16613 9 of 15 Table 6. Independent variables and coefficients of the logarithmic HPM model (r = 0.816, R2 = 0.667, p ≤0.001) (Own elaboration). Variables Coefficients Stand. Error Student’s t Prob. VIF Constant 6.56 1.49 4.36 0.000 - Room 1.39 1.08 1.29 0.000 1.705 Baths (n◦) 0.26 0.6 0.432 0.000 1.523 Age (years) −0.365 0.205 −1.78 0.000 1.380 Green area (m2/inh) −0.013 0.13 −0.1 0.000 1.000 If the reciprocal model is analyzed, Equation (8) is obtained (r = 0.647, R2 = 0.42, p ≤0.05): P = 5581.151 −344, 864.49·  1 S  (8) After the reciprocal model’s price estimation (Figure 3) is represented, it can be ob- served that the price function shape in the limit, “P” trends towards “α = 5581.151”. The term “−(β/α)” refers to the smallest amount of surface available in a dwelling (61.79 m2 in this study). Figure 3. Reciprocal model representation when “α > 0” and “β < 0”. (Own elaboration). If the three models are compared based on the coefficient of determination (R2), it can be said that a higher value of this coefficient implies a better estimate of the housing price. For this reason, the linear model explains 5.4% more of the predicted price than the logarithmic model and 30.1% more than the reciprocal model. On the other hand, the logarithmic model explains 24.7% more of the estimated price than the reciprocal model. Additionally, the Chow test [40] was used to ensure the models’ stability. It should be noted though that the Chow test has its origin in economics. Nevertheless, it has also been applied to other fields such as renewable energies [41], flood risk assessment [42], and spatiotemporal disease diffusion [43]. In this study, the results revealed that no structural changes occurred exclusively in the parameters of either the linear or logarithmic models. This can be seen in Figure 4, which compares the real price (from www.idealista.com (accessed on 18 October 2022)) to the estimated price for each model used. As can be seen, Figure 4 allows for the simulation of hypotheses that facilitate the validity of the study to be tested. ===== PAGE 10 (score 10, numeric-paren 0, table-words 1, var-words 8) ===== Sustainability 2022, 14, 16613 10 of 15 Figure 4. Comparison of real (www.idealista.com (accessed on 17 October 2022)) versus estimated prices for each HPM model. (Own elaboration). When the models’ degree of fit is perfect, they should appear as point clouds in a diagonal line starting at the origin (1017.51; 1119.94 in this study), as shown in Figure 4. In this case, the estimated values for linear and logarithmic models indicate that the linear form is a good fit. However, the reciprocal model presents a trend line that does not coincide with the indicated origin. For this reason, the model does not have as much stability as the linear and logarithmic ones. Furthermore, with regard to the kriging, Figure 5 shows the geostatistical price interpo- lation for the city of Seville. As is well known, in order to perform predictions using kriging the forecasting system must be geometrically defined at some point. This means that we must establish the neighbourhood of the data that will intervene in the approximation. It is possible to use all the dwelling prices (assuming a global neighbourhood) and a set of data (considering a local neighbourhood) in the estimation. In practice, only house prices within a predefined circumference or ellipse centred on the estimated point are used. Obviously, the proximity of the data for each point to be valued will differ, thereby necessitating a different kriging equations system for each point on the map at which a prediction is desired. On the other hand, this method allows for the synthetic representation of housing price estimates in the form of a colour map. This representation is generated by performing predictions on the nodes of a regular mesh. In this manuscript the housing price has been estimated at each node of a 10-m-sided regular mesh. The map in Figure 5 displays how the more valuable areas coincide with those closest to the city centre. The least valued areas, on the other hand, are primarily in the districts of San Jerónimo-Pino Montano, Torreblanca-Sevilla Este-Parque Alcosa, and Cerro-Amate. This is primarily due to a shift in buyer preferences following the COVID-19 pandemic. Following confinement the percentage increase in the preference for housing (new or used) with a balcony was around 80% [44]. As a result, the average percentage decrease in housing prices was 5% across the districts, except for the Centro district which is dominated by homes with small balconies and a communal roof terrace. In order to compare the kriging values in terms of €/m2 with those of the analyzed models, Table 7 lists the average values per district corresponding to the centroid established in the geospatial analysis.