# RECORD 8674ce1937729ab9e1f1084511ae7a29ecdbc635 # TITLE: The Role of Subjective Perceptions and Objective Measurements of the Urban Environment in Explaining House Prices in Greater London: A Multi-Scale Urban Morphology Analysis # YEAR: 2023.0 VENUE: ISPRS Int. J. Geo Inf. DOI: 10.3390/ijgi12060249 # AUTHORS: Sijie Yang; K. Krenz; Waishan Qiu; Wen-Jing Li # PAGES: 21 CANDIDATE TABLE PAGES (1-based): [9, 13, 14, 15, 16] # ABSTRACT: House prices have long been closely related to the built environment of cities, yet whether the subjective perception (SP) of these environments has a differing effect on prices at multiple urban scales is unclear. This study sheds light on the impact of people’s SP of the urban environment on house prices in a multi-scale urban morphology analysis. We trained a machine learning (ML) model to predict people’s SP of the urban environment around properties across Greater London with survey response data from an online survey evaluating people’s SP of street view image (SVI) and linked this to house price data. This information was used to construct a hedonic price model (HPM) and to evaluate the association between SP and house price data in a series of linear regression models controlling location information and urban morphological characteristics such as street network centralities at multiple urban scales, quantified using space syntax (SS) methods. The findings show that SP influences house prices, but this influence differs depending on the urban scale of analysis. Particularly, a sense of ‘enclosure’ and ‘comfort’ are important factors influencing house price variation. This study contributes by introducing SP of the urban environment as a new dimension into the traditional HPM and by exploring the economic impact of SP on the house price market at multiple urban scales. ===== PAGE 1 (score 0, numeric-paren 0, table-words 0, var-words 0) ===== 6.2 3.099 The Role of Subjective Perceptions and Objective Measurements of the Urban Environment in Explaining House Prices in Greater London: A Multi-Scale Urban Morphology Analysis Sijie Yang, Kimon Krenz, Waishan Qiu and Wenjing Li Article https://doi.org/10.3390/ijgi12060249 ===== PAGE 9 (score 12, numeric-paren 0, table-words 3, var-words 4) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 8 of 20 models. Backpropagation and its application to neural networks were first proposed and further developed by Rumelhart et al. [86]. This multilayer perceptual model can cope with arbitrarily complex patterns for classification and provides sufficient multi-dimensional function mapping. As shown in Figure 5, in this study, the view indexes of 30 physical elements in a single SVI, e.g., Vsky, Vwall, Vtree, constitute the input layer. After the function calculation in the hidden layer, the output layer yields the scores of this image on eight subjective perceptual attributes, e.g., Simageability, Senclosure, Shuman scale. The BP neural net- work model was used as a classifier to rate each SP variable of each SVI as an integer score ranging from 1–5 based on the information from the SVI segmentation. The data for the pre-trained model are derived from the results of the online perception survey based on 300 pre-determined SVIs and view indexes extracted from these images. Eighty percent of the data are used as a training set to build the BP neural network model, while 20% are used as a testing set to assess the model’s accuracy.   Figure 5. Algorithms diagram of Backprop Neural Network. Accuracy, Precision, Recall, and F1 Score evaluate the prediction performance of a model. The best-performing model was then used to predict the SP scores for all 70,059 SVIs. The streetscape perception scores within 1 km of a property were averaged to represent the quality of the street environment in the property’s neighborhood. However, it is acknowledged that what constitutes a neighborhood can vary in size and scale based on individual preferences. Descriptive statistics for the SP scores of the street environment around each property are presented in Table 2. In Figure 6, one can see that the SVIs are seg- mented according to physical features to obtain visual indices of different physical features. Subsequently, the subjective streetscape perception scores are predicted by the ML model. Table 2. Descriptive statistics of all variables. Variable Description Count Mean Std.Dev. Min Max Data Source PRICE £/m2, dependent variable 49,603 6793.59 3427.28 117.77 91,866.95 LR-PPD data House Structure attribute H1_FLARA Total floor area (m2) 49,603 91.25 57.15 6.26 4373.00 EPCs data H2_INSUP House insulation performance 49,603 2.58 1.63 1.00 5.00 H3_LIGTP House lighting performance 49,603 3.69 1.52 1.00 5.00 H4_HOTWP House hot water performance 49,603 3.80 0.89 1.00 5.00 H5_CO2EM House CO2 Emission 49,603 2.00 1.62 −1.40 66.00 ===== PAGE 10 (score 24, numeric-paren 0, table-words 1, var-words 10) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 9 of 20 Table 2. Cont. Variable Description Count Mean Std.Dev. Min Max Data Source Description Values Count Percent Avg.Price Avg.Area Data Source H6_FLLEV Floor level 1: Low 15,959 32.17% 6908.76 65.03 EPCs data 2: Mid 32,093 64.70% 6698.90 105.08 3: High 1551 3.13% 7571.03 74.85 H7_PROTY Property type 1: Detached 3464 6.98% 6123.85 174.60 2: Flat 24,841 50.08% 7539.41 67.13 3: Semi 7961 16.05% 5683.22 113.49 4: Terrace 13,337 26.89% 6244.62 101.24 H8_MENER Main energy source 1: Electricity 4626 9.33% 6602.96 63.06 2: Gas/LPG 38,167 76.94% 6409.88 97.83 3: Oil/Coal 101 0.20% 6684.66 100.98 4: Others 6709 13.53% 9111.52 73.11 Subjective urban perception variable Count Mean Std.Dev. Min Max Data Source S1_IMBLY Perceived imageability 49,603 3.05 0.36 1.00 4.16 SVIs, Investi- gation data, ML results S2_ENCLS Perceived enclosure 49,603 2.86 0.46 1.50 4.65 S3_HMSCL Perceived human scale 49,603 3.06 0.26 1.00 4.29 S4_TRANS Perceived transparency 49,603 2.82 0.20 2.00 4.00 S5_CMPLY Perceived complexity 49,603 3.24 0.27 1.33 4.00 S6_SAFTY Perceived sense of safety 49,603 3.24 0.22 1.00 4.50 S7_COFRT Perceived sense of comfort 49,603 3.03 0.21 2.00 4.00 S8_INTST Perceived level of interest 49,603 3.09 0.17 2.00 4.33 Objective urban perception variable Count Mean Std.Dev. Min Max Data Source Location Attribute (Urban morphology) L1_D2CBD Cost network distance to CBD 49,603 0.30 0.15 0.02 0.81 OS data L2_POSDT Postcode District 49,603 / / / / M1_INT400 Space syntax-Integration[HH] (R400) 49,603 23.18 6.63 3.56 68.69 M2_CH400 Space syntax-Choice (R400) 49,603 108.54 59.18 0.00 902.55 M3_INT800 Space syntax-Integration[HH] (R800) 49,603 49.09 20.54 3.56 176.85 M4_CH800 Space syntax-Choice (R800) 49,603 788.61 485.01 0.00 6399.87 M5_INT2000 Space syntax-Integration[HH] (R2000) 49,603 155.50 88.85 3.56 575.72 M6_CH2000 Space syntax-Choice (R2000) 49,603 11,141.62 7914.72 0.00 47,980.45 M7_INT6000 Space syntax-Integration[HH] (R6000) 49,603 650.86 459.06 3.56 2148.27 M8_CH6000 Space syntax-Choice (R6000) 49,603 272,714.0 249,841.4 0.00 1,552,460 Neighbourhood and Environment Attribute (Urban Functional Property) F1_DENLS Density of urban services (within 1 km) 49,603 341.28 384.77 0.00 5515.00 OS data F2_DENWK Density of workplace (within 1 km) 49,603 337.43 463.93 1.00 5880.00 F3_DENAT Density of attraction (within 1 km) 49,603 27.36 40.80 0.00 572.00 F4_D2UDG Distance to TfL station (km) 49,603 0.75 0.58 0.00 7.26 TfL data F5_A2UDG Accessibility to TfL station (within 3 km) 49,603 15.94 13.04 0.00 70.00 F6_D2SCH Distance to quality school (km) 49,603 0.56 0.40 0.00 6.94 Ofsted data F7_A2SCH Accessibility to quality school (within 3 km) 49,603 24.93 14.76 0.00 83.00 ===== PAGE 13 (score 17, numeric-paren 0, table-words 4, var-words 5) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 12 of 20 3. Results 3.1. Subjective Urban Perception Prediction 3.1.1. Accuracy of the Machine Learning Prediction Model The prediction performance and model evaluation of the BP neural network model on the SP scores of the urban street environments are shown in Table 3. The model performed on average moderate or above for all subjective perceptual variables, with values greater than 0.5 based on a generally accepted rule of thumb evaluation criteria. The best-performing perceptual prediction models are models of ‘imageability’ (S1), ‘human scale’ (S3), ‘transparency’ (S4), ‘sense of comfort’ (S7), and ‘level of interest’ (S8), all with accuracy greater than 0.7, of which ‘human scale’ has the highest accuracy of 0.795. The prediction models for ‘enclosure’ and ‘sense of safety’ are less accurate at 0.643 and 0.652, respectively, while the model for ‘complexity’ has the lowest accuracy at 0.579. The accuracy of the SP model predictions in this study is relatively high, ranging from 0.58 to 0.80, which is a significant improvement compared to previous studies, with R2 of Verma, et al.’s prediction model [98] ranging from 0.20 to 0.66, and R2 of Qiu, Zhang, Liu, Li, Li, Xu and Huang’s perception prediction model [30] ranging from 0.47 to 0.61. Table 3. Performance of BP Neural Network predictions. Perception Accuracy Precision Recall F1-Score Criteria S1. Imageability 0.710 0.731 0.725 0.721 Good S2. Enclosure 0.643 0.630 0.666 0.629 Moderate S3. Human Scale 0.795 0.785 0.780 0.779 Good S4. Transparency 0.722 0.723 0.732 0.724 Good S5. Complexity 0.579 0.628 0.613 0.613 Moderate S6. Sense of Safety 0.652 0.657 0.664 0.659 Moderate S7. Sense of Comfort 0.720 0.726 0.732 0.716 Good S8. Level of Interest 0.711 0.737 0.724 0.729 Good Evaluation criteria: >90% very good, 70–90% good, 60–70% moderate, <60% low. A higher accuracy indicates fewer variations in survey scores, which in turn may imply that these SP dimensions can be better understood by respondents [5,30]. Imageability (S1), human scale (S3), transparency (S4), sense of comfort (S7), and level of interest (S8), all show higher levels of accuracy whereas complexity (S5) showed lower levels of accuracy, hinting towards a more ambiguous perception of the latter. 3.1.2. Spatial Heterogeneity of Urban Subjective Perception Figure 7 shows the spatial distribution of SP prediction results, with clear spatial patterns for some SP variables. For the three SP variables of ‘imageability’ (S1), ‘enclosure’ (S2), and ‘complexity’ (S5), there is a strong tendency for the ratings to cluster geographically towards the city center, with enclosure being the most pronounced. This phenomenon can be explained by the high density of buildings in the city center, where the presence of buildings makes the street space more impressionistic and more enclosed and adds to the diversity and complexity of the urban space. For the three variables ’human scale’ (S3), ‘transparency’ (S4), and ‘sense of safety’ (S6), the geographical distributions are reversed, with scores highly concentrated in the periphery of the city. The urban periphery, with fewer buildings and more greenery, is considered by respondents to have a ‘human scale’ (S3), ‘transparency’ (S4), and a ‘sense of safety’ (S6). The spatial distributions of ‘sense of comfort’ (S7) and ‘level of interest’ (S8) ratings are scattered across the research region, with interest scores being the most dispersed, suggesting that people’s perceptions in these two SP dimensions are more complex. ===== PAGE 14 (score 25, numeric-paren 8, table-words 8, var-words 0) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 13 of 20   Figure 7. Spatial distribution of properties with SP scores. 3.2. Spatial Hedonic Price Model Result 3.2.1. Correlation of Each Attribute Group with House Prices Table 4 shows the strength of the four attribute dimensions that make up the HPM in explaining house prices (p < 0.01). Location attributes, i.e., urban morphology attributes, are the strongest in explaining house prices (R2 = 0.427), followed by SP scores (R2 = 0.342) and neighborhood attributes (R2 = 0.339). The weakest influencing attribute group is the set of house structure attributes (R2 = 0.085). Table 4. Model performance of each attribute group. OLS Diagnosis House Structure Attributes Location Attributes (Urban Morphology) Neighborhood Attributes (Urban Function) Subjective Perception Scores Adjusted R2 0.085 *** 0.427 *** 0.342 *** 0.342 *** Pr. (F-statistic) 0.000 *** 0.000 *** 0.000 *** 0.000 *** *** p < 0.01 level. 3.2.2. Results of Regression Models with Multi-Scale Urban Morphology The OLS model results are shown in Table 5, and the impact ranking of each of the five urban scale models is shown in Figure 8 respectively. The baseline model (Model 0) ===== PAGE 15 (score 112, numeric-paren 90, table-words 6, var-words 0) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 14 of 20 uses traditional location attributes, i.e., the property’s network cost distance to the CBD (L1_D2CBD) and its postcode district (L2_POSDT). The other models (Model 1–4) apply different scales of integration and choice as location attributes of the HPM. Table 5 shows the regression model’s performance and diagnostic outcomes. The adjusted R2 indicates a comparable association with house prices among the five models. When comparing Model 0 and Model 4, the overall performance of the two models is comparable after replacing the traditional location attributes with the urban morphology variables of space syntax (R2 = 0.496, R2 = 0.494). However, the integration variable in Model 4 (M7_INT6000, M8_CH6000) increases the models standardized coefficients, as shown in Figure 8. Such a result suggests that integration captures characteristics of the urban environment that influence house prices that traditional location attributes have been unable to represent. Table 5. Regression with multi-scale urban morphology: results and diagnosis. Model 0 Model 1 Model 2 Model 3 Model 4 Location Attribute Baseline (L1, L2) M1, M2 (R400) M3, M4 (R800) M5, M6 (R2000) M7, M8 (R6000) Adjusted R2 0.496 *** 0.482 *** 0.484 *** 0.486 *** 0.494 *** Pr. (F-statistic) 0.000 *** 0.000 *** 0.000 *** 0.000 *** 0.000 *** Variable Coef. P > t Coef. P > t Coef. P > t Coef. P > t Coef. P > t CONSTANT *** *** *** *** *** House Structure attribute H1_FLARA −0.007 −0.009 ** −0.012 ** −0.014 ** −0.016 *** H2_INSUP −0.009 ** −0.006 −0.001 −0.001 0.004 H3_LIGTP −0.039 *** −0.037 *** −0.036 *** −0.036 *** −0.035 *** H4_HOTWP 0.002 0.002 0.001 0.002 0.003 H5_CO2EM 0.054 *** 0.059 *** 0.059 *** 0.06 *** 0.059 *** H6_FLLEV 0.068 *** 0.062 *** 0.063 *** 0.062 *** 0.066 *** H7_PROTY −0.026 *** −0.02 *** −0.021 *** −0.021 *** −0.02 *** H8_MENER 0.122 *** 0.135 *** 0.136 *** 0.134 *** 0.137 *** Subjective urban perception variable S1_IMBLY 0.024 *** 0.032 *** 0.031 *** 0.035 *** 0.029 *** S2_ENCLS 0.135 *** 0.157 *** 0.16 *** 0.164 *** 0.125 *** S3_HMSCL 0.043 *** 0.037 *** 0.035 *** 0.033 *** 0.027 *** S4_TRANS −0.022 *** −0.009 *** −0.009 *** −0.01 *** −0.017 *** S5_CMPLY 0.028 *** 0.034 *** 0.028 *** 0.028 *** 0.026 *** S6_SAFTY −0.039 *** −0.051 *** −0.051 *** −0.052 *** −0.048 *** S7_COFRT 0.112 *** 0.124 *** 0.126 *** 0.123 *** 0.112 *** S8_INTST −0.043 *** −0.044 *** −0.044 *** −0.041 *** −0.037 *** Objective urban perception variable Location Attribute (Urban Morphology) L1_D2CBD −0.098 *** / / / / L2_POSDT 0.136 *** / / / / M1_INT400 / 0.115 *** / / / M2_CH400 / −0.052 *** / / / M3_INT800 / / 0.217 *** / / M4_CH800 / / −0.14 *** / / M5_INT2000 / / / 0.286 *** / M6_CH2000 / / / −0.185 *** / M7_INT6000 / / / / 0.324 *** M8_CH6000 / / / / −0.087 *** ===== PAGE 16 (score 45, numeric-paren 35, table-words 2, var-words 3) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 15 of 20 Table 5. Cont. Model 0 Model 1 Model 2 Model 3 Model 4 Neighborhood Attribute (Urban Functional Property) F1_DENLS 0.135 *** 0.111 *** 0.088 *** 0.087 *** 0.102 *** F2_DENWK −0.137 *** −0.177 *** −0.165 *** −0.164 *** −0.181 *** F3_DENAT 0.419 *** 0.486 *** 0.479 *** 0.456 *** 0.437 *** F4_D2UDG −0.028 *** −0.019 *** −0.018 *** −0.021 *** −0.02 *** F5_A2UDG 0.048 *** 0.044 *** 0.046 *** 0.041 *** 0.009 *** F6_D2SCH 0.041 *** 0.031 *** 0.032 *** 0.03 *** 0.034 *** F7_A2SCH −0.071 *** −0.039 *** −0.045 *** −0.067 *** −0.126 *** ** p < 0.05 level, *** p < 0.01 level.   Figure 8. Impact ranking in models based on absolute standardized coefficients. For models 1–4, while different scales of urban morphology are used as the location attribute, no significant change in R2 can be observed. Meanwhile, the density of attractions (F3_DENAT) exhibits the highest standardized coefficient among all models, implying that being close to functional opportunities has a greater influence on house prices than being closer to generic opportunities. Other important functional variables include the density of workplaces (F2_DENWK) and the density of urban services (F1_DENLS). The models also show that the effect of people’s SP varies depending on varying urban morphological scales. At a relatively large scale, i.e., a radius of 6 km (Model 4), the integration variable (M7_INT6000) can better explain house price variation, than the SP variables ‘enclosure’ and ‘sense of comfort’ (S2_ENCLS, S7_COFRT). The importance diminishes as the scale decreases (Model 2, Model 3) and eventually falls below some SP variables (Model 1). The choice variable has a similar trend in Models 1–3 but is not as noticeable as the integration value. In terms of SP attributes, ‘enclosure’ and ‘sense of comfort’ can best explain house price variation, followed by ‘safety’ and ‘interest’, whereas ‘imageability’, ‘transparency’ and ‘complexity’ are the lowest. This result indicates that when holding other conditions equal, ===== PAGE 17 (score 6, numeric-paren 0, table-words 1, var-words 4) ===== ISPRS Int. J. Geo-Inf. 2023, 12, 249 16 of 20 people’s SP plays a role in shaping the house price market. Particularly areas featuring a sense of enclosure and which are also comfortable to live in tend to be more valued than other places. 4. Conclusions The findings show that SP of the built environment has a significant effect on house prices. This effect is higher than neighborhood attributes (i.e., urban functions) or house structure attributes. However, our analysis has shown that location attributes (i.e., urban morphology) have a higher importance than SP attributes. This suggests that people’s SP variables of the urban environment have significant impacts on house prices, above some objective urban environment attributes. The HPM based on multi-scale urban morphology shows that when comparing urban morphological attributes with SP attributes, the smaller the scale of urban morphology (i.e., the more local the measure), the more important is the SP. Moreover, the larger the scale of urban morphology (i.e., the more global the measure), the more important are the urban morphological attributes. For the different SP variables, ‘enclosure’ (S2_ENCLS) and ‘sense of comfort’ (S7_COFRT) have more significant impacts on house prices than other variables. This study adds the SP dimension to the house price assessment model, helping to explore the impact of SP on house prices at different scales of urban morphology. Future related research could refer to such a framework using SVI data and SP surveys to incorporate people’s SP of the urban streetscape near the property into house price assessment at multiple urban scales supported by SS techniques. 5. Limitation and Future Work There are several limitations to this study. First, this study only used visual indices from SVI segmentation in building an SP prediction model. The prediction accuracy of this approach may be improved by increasing the quality and precision of SVI data extraction and expanding the volume of perception survey data: (i) more features, such as HSL histograms and Blob detection, may be added to complement the physical features presented by the SVIs; (ii) more field experiences and surveys may be added to the study to cross-validate the SP predictions and minimize the bias introduced by web image surveys. Second, in the SP survey, some participants’ understanding of the concepts of SP may not accurately capture their perception. A better questionnaire design and question setting as well as a larger sample size could improve this limitation. Future research could involve a larger more representative sample including urban design professionals to provide a more accurate and efficient assessment of the street environment in images. In addition, VR technology and panoramic SVIs can be used in the perception survey sessions to provide participants with a more realistic environment and more accurate exploration of their SP. Finally, many studies have shown that spatial dependence and non-stationarity violate the basic assumptions of OLS regression. Due to spatial correlation effects, OLS regression models may be biased in their coefficients and report incorrect significance. More tests for OLS regression may be carried out, such as Moran’s I and robust Lagrange multiplier (LM) tests, to see if lags and errors due to spatial correlation exist. Given there are spatial lags or errors in OLS regression models, other regression models that solve for spatial dependence may be introduced for more accurate multi-factor impact studies, including the Kelejian– Prucha’s model (SAC) [99] and geographically weighted regression (GWR) [100]. These models can effectively manage spatial dependence and non-stationarity-related issues and achieve higher R2 values, thereby enhancing the models’ precision and providing stronger data support for the paper’s conclusions [51,55]. Author Contributions: Conceptualization, Sijie Yang, Kimon Krenz, and Waishan Qiu; methodology, Sijie Yang, Kimon Krenz, and Wenjing Li; software, Sijie Yang; validation, Sijie Yang; formal analysis, Sijie Yang; investigation, Sijie Yang; resources, Wenjing Li; data curation, Sijie Yang; writing—original draft preparation, Sijie Yang; writing—review and editing, Kimon Krenz and Waishan Qiu; visualiza-