Objective  In the post-epidemic era, as residential and office routines gradually return to normalcy, there has been a notable surge in the demand for residential green spaces. The rejuvenation of these spaces holds significant importance for individuals seeking solace and tranquility in their surroundings. While previous researches predominantly focus on ground-level greening characteristics of outdoor spaces in settlements, it is equally crucial to explore people’s preferences for green spaces in high-rise settlements from an overhead perspective. In view of this, this research aims to delve into the following three key issues: 1) Quantification of the greening characteristics of outdoor space perceived by individuals at different heights and examination of corresponding changes in their psychological preferences through the application of advanced technical means; 2) elucidation of the correlation between the characteristics of outdoor space greening patterns and people’s perception preferences from an overhead perspective, along with the specific effects these patterns have on individuals; 3) exploration of the practical applications of the research findings for subsequent settlement planning and design and policy formulation, based on an in-depth analysis of outdoor space greening patterns from the perspective of people’s overhead preferences.

Methods  To achieve the aforesaid objectives, three exemplary high-rise residential areas in Nanjing are selected as research object. To ensure a comprehensive understanding of the relationship between people’s preferences and the greening of outdoor spaces, the research adopts a variety of technical methods such as aerial drone photography, LiDAR scanning and 3D visual simulation, together with relevant mathematical decision-making means, making it possible to establish a robust correlation between people’s overhead preferences at different heights and corresponding indicators of overhead greening patterns. The research workflow comprises three primary stages. Firstly, five spatial pattern indicators are carefully chosen to effectively describe the multidimensional pattern changes of outdoor space greening from an overhead perspective. These indicators encompass the three-dimensional visible greening volume, greening compactness, greening extension, proportion of greening view, and greening complexity. Secondly, to capture the essence of people’s overhead preferences, the research adopts the following four perceptual indicators: nature, order, species richness and serenity. These indicators are derived from detailed questionnaires distributed to participants. Subsequently, by quantifying and analyzing the identified indicators, the research conducts a comprehensive correlation analysis. This analysis aims to establish the relationship between the spatial pattern indicators and the perceptual indicators, thereby illuminating the specific influence of various factors and identifying key indicators. Finally, based on the insights garnered from research results, the research conducts an extensive discussion regarding the main findings, potential practical applications, and future research directions.

Results  The findings of this research unveil significant insights into the intricate relationship between people’s preferences for greening characteristics in high-rise settlements and their observations at different overhead heights. The analysis reveals an intriguing inverse relationship between the height of observation and three key greening characteristics, namely the three-dimensional visible greening volume, greening complexity, and greening compactness. Conversely, a positive relationship is observed between observation height and greening extension, as well as the proportion of greening view. Moreover, the research sheds light on the perceptual indicators and reveals a discernible pattern in people’s overhead preferences. Specifically, the indicators of order and species richness exhibit a positive correlation with floor height, suggesting that as the floor height increases, individuals perceive an augmented richness and orderliness in the vegetation surrounding the settlement. Conversely, the indicators of serenity, nature, and overall preference demonstrate an inverse relationship with floor height, indicating an amplified perception of overhead preference as floor height increases. Notably, strong correlations are observed between the indicators of serenity, nature, preference, and overhead greening. In contrast, the two overhead preference indicators of richness and orderliness demonstrate a weaker correlation with overhead greening indicators.

Conclusion  The findings of this research contribute empirical evidence highlighting the pronounced variations in people’s preferences for greening characteristics in high-rise settlements, particularly when considering observations at different overhead heights. The results establish a compelling correlation between people’s overhead preferences and the greening patterns they observe. Two key indicators of greening pattern, namely greening complexity and the three-dimensional visible volume of greening, emerge as influential factors shaping people’s overhead preferences. Furthermore, in terms of people’s overhead preferences, three key indicators, serenity, nature, and overall preference, are found to aptly reflect people’s perceptions of high-rise settlements from an overhead perspective. Importantly, the correlation between people’s overhead preferences and the characteristics of outdoor space greening shows a consistency across different settlement layouts, premised on the identical floor heights. The incorporation of an “overhead perspective” to comprehensively comprehend changes in people’s perception adds a novel dimension and viewpoint to landscape researches, positioning it as a pivotal indicator for evaluating people’s overhead perceptions in future research and practice. The findings from this research are of practical implications for refining regulations pertaining to settlement planning and design. Additionally, they serve as a foundation for fostering high-quality outdoor spaces that cater to the diverse spectrum of perceptual preferences among residents. To further enrich this field, future research should explore additional avenues for improvement, building upon the valuable insights gained from this research.