scholarly journals Mapping Public Urban Green Spaces Based on OpenStreetMap and Sentinel-2 Imagery Using Belief Functions

2021 ◽  
Vol 10 (4) ◽  
pp. 251
Author(s):  
Christina Ludwig ◽  
Robert Hecht ◽  
Sven Lautenbach ◽  
Martin Schorcht ◽  
Alexander Zipf

Public urban green spaces are important for the urban quality of life. Still, comprehensive open data sets on urban green spaces are not available for most cities. As open and globally available data sets, the potential of Sentinel-2 satellite imagery and OpenStreetMap (OSM) data for urban green space mapping is high but limited due to their respective uncertainties. Sentinel-2 imagery cannot distinguish public from private green spaces and its spatial resolution of 10 m fails to capture fine-grained urban structures, while in OSM green spaces are not mapped consistently and with the same level of completeness everywhere. To address these limitations, we propose to fuse these data sets under explicit consideration of their uncertainties. The Sentinel-2 derived Normalized Difference Vegetation Index was fused with OSM data using the Dempster–Shafer theory to enhance the detection of small vegetated areas. The distinction between public and private green spaces was achieved using a Bayesian hierarchical model and OSM data. The analysis was performed based on land use parcels derived from OSM data and tested for the city of Dresden, Germany. The overall accuracy of the final map of public urban green spaces was 95% and was mainly influenced by the uncertainty of the public accessibility model.

2021 ◽  
Vol 12 (2) ◽  
pp. 83-92
Author(s):  
Aigul SERGEYEVA ◽  
Altynbek KHAMIT ◽  
Asima КOSHIM ◽  
Murat MAKHAMBETOV

The rapid pace of urban development triggers complex problems mostly related to urban environment pollution, and shortcomings of city’s improvement. The modern city is characterized by the highest man-made pressure on the natural environment, the main problems being overcrowding, lack of open-access green areas, as well as the decrease of vegetation areas, fact that does not create comfortable living conditions for urban residents. At present, remote sensing methods are some of the priority tools used in vegetation state assessment, particularly, the calculation of vegetation index (NDVI). But often, obtaining the necessary information is limited only to the analysis of satellite data, without geobotanical field surveys, which considerably increase the reliability of the detected results. In addition, the definition of dependencies when using an integrated approach of different man-affected surfaces with a different type of overgrowth within the city remains insufficiently studied. The purpose of this study is to assess the ecological condition of the green area (parks and squares) in Aktobe city. A comprehensive processing of satellite images including the calculation of NDVI index, mapping of green areas and data statistical analysis, was carried out. We learned that the average value of NDVI for green spaces in Aktobe ranges from 0,11 µm to 0,47 µm, which allows for the categorization of planted areas by levels of photosynthetic activity, from “unsatisfactory” to “good”, yet, with 59% of them in an unsatisfactory condition. This means that the city is underdeveloped in terms of modern landscape and infrastructure. The obtained results make it possible to assess the current situation, determine the dynamics of urban green spaces and optimize spatial planning measures for green space management.


Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 155
Author(s):  
Filoteo Gomez-Martinez ◽  
Kirsten M. de Beurs ◽  
Jennifer Koch ◽  
Jeffrey Widener

The urban heat island (UHI) effect is a global problem that is likely to grow as a result of urban population expansion. Multiple studies conclude that green spaces and waterbodies can reduce urban heat islands. However, previous studies often treat urban green spaces (UGSs) as static or limit the number of green spaces investigated within a city. Cognizant of these shortcomings, Landsat derived vegetation and land surface temperature (LST) metrics for 80 urban green spaces in Puebla, Mexico, over a 34-year (1986–2019) and a 20-year (2000–2019) period were studied. To create a photo library, 73 of these green spaces were visited and the available land cover types were recorded. Green spaces with Indian laurel were found to be much greener and vegetation index values remained relatively stable compared to green spaces with mixed vegetation cover. Similarly, green spaces with large waterbodies were cooler than those without water. These results show that larger green spaces were significantly cooler (p < 0.01) and that size can explain almost 30% of temperature variability. Furthermore, green spaces with higher vegetation index values were significantly cooler (p < 0.01), and the relationship between greenness and temperature strengthened over time.


Author(s):  
J. E. Patiño

Abstract. The availability of green spaces is an important issue for urban populations worldwide, given the benefits that the green spaces provide for health, well-being, and quality of life. But urban green spaces are not always distributed equally for different population groups within cities. Latin America is the second most urbanized region of the world, but there are few published studies analysing the green space availability for different urban population groups, and less so analysing the long-term trends. This work presents an analysis of long-term availability of urban green spaces by different socioeconomic status population groups in Medellin city, Colombia, using open geospatial data and open software tools. The results indicate that disparities between different groups have been decreasing in the last years, but there are still efforts to do. Showing this kind of analysis based on open data and tools is essential as it opens the possibility for replicating it in other cities with scarce budgets.


Author(s):  
Juliana Melo ◽  
Ana Isabel Ribeiro ◽  
Susana Aznar ◽  
Andreia Pizarro ◽  
Maria Paula Santos

Environmental factors play an important role in obesity-related behaviors. Evidence indicates significant associations between weight and urban green spaces in adults, but it is not clear whether this relationship applies to adolescents. Therefore, our aim was to determine the associations between urban green spaces, greenness exposure and species richness in residential environments with physical activity and body mass index. Sixty-two adolescents between 12 and 18 years of age answered a self-administered questionnaire, providing information on height, weight, age, sex and home address. Data on socioeconomic deprivation were obtained from the European Index of Deprivation for Small Portuguese Areas. Physical activity levels were assessed using accelerometers. Urban green space counts and the normalized difference vegetation index values were measured using buffers along the roads with distances of 300, 500, 1000 and 1500 m from each participant’s residence. To quantify the species richness, the species richness index was used. Linear regression models were fitted to analyze whether urban green spaces, exposure to green spaces and species richness counts for each distance were associated with physical activity and self-reported body mass index. We did not find significant associations between the independent variables and the probability of overweight or obesity. The relationship between environmental variables, adolescents’ physical activity and body weight seems to be complex and further studies may contribute to better understanding of the topic.


2020 ◽  
Vol 9 (10) ◽  
pp. 586
Author(s):  
Kee Moon Jang ◽  
Jaeman Kim ◽  
Hye-Yeong Lee ◽  
Hyemin Cho ◽  
Youngchul Kim

Advancements in remote sensing techniques and urban data analysis tools have enabled the successful monitoring and detection of green spaces in a city. This study aims to develop an index called the urban green accessibility (UGA) index, which measures people’s accessibility to green space and represents the citywide or local characteristics of the distribution pattern of green space. The index is defined as the sum of pedestrians’ accessibility to all vegetation points, which consists of the normalized difference vegetation index (NDVI) with integration and choice values from angular segment analysis. In this study, the proposed index is tested with cases of New York, NY, and San Francisco, CA, in the US. The results reveal differences based on the significance of streets. When analysis ranges are on a neighborhood scale, a few hotspots appear in well-known green areas on commonly accessible streets and in local neighborhood parks on residential blocks. The appearance of high-accessibility points in low-NDVI areas implies the potential of the efficient and proper distribution of green spaces for pedestrians. The proposed measure is expected to help in planning and managing green areas in cities, taking people’s accessibility and spatial relationships into consideration.


2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Viet Nghia NGUYEN ◽  
Le Hung TRINH ◽  
Thi Thu Nga NGUYEN ◽  
Thi Le LE

This paper presents the results of an assessment of change in urban green spaces in Thanh Hoacity (Vietnam). Sentinel 2 MSI data in 2015 and 2021 are used to calculate 3 parameters: percentage ofgreen, weight of green types, and weight of proximity to green. These parameters are used to calculate theWeighted Urban Green Space Index (WUGSI). The final result shows the distribution of green space inthe study area consisted of very high-quality green, high-quality green, moderate quality green, and lowquality green. The obtained results show that the quality of urban green space in Thanh Hoa city haschanged significantly in the period 2015-2021, in which the area with category “low quality green space”increased from 7.17% up to 9.48%; areas with category “very high-quality green space” reduced from65.02% to 47.39%.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Archana Bele ◽  
Ujwala Chakradeo

Abstract The significance of biodiversity in the survival of human beings and enhancing the urban quality of life is evident from the empirical measurements and qualitative studies carried out across the globe. Despite its importance and value, burgeoning population and growing urbanization are posing a serious threat to biodiversity leading to biodiversity homogenization and ecosystem fragmentation. Moreover, studies reveal that management practices of biodiversity hardly take into account perception, needs, and knowledge of urban residents regarding biodiversity. Urban green spaces have a major role to play in the conservation of urban biodiversity. However, the triangular relationship between biodiversity, urban green spaces, and public perception is still unexplored. With this aim, the paper attempts to compile, analyze, and synthesize the empirical findings to understand the state-of-the-art knowledge regarding public perception of biodiversity in urban green spaces. The search strategy acquired for the selection of papers resulted in 43 papers from 22 different countries of the world. The paper focuses upon an inclusive definition of urban green spaces, thus encompasses a wide variety of urban and peri-urban green spaces, parks, gardens, and waterfront urban spaces. The analysis of literature pattern reveals a recent increase in studies related to biodiversity perception over the last 10 years. It indicates a strong geographic bias in publications as well. Studies of animals including birds, insects, and reptiles are found scarce compared to plant species. The study could identify potential variables affecting human biodiversity perception which include species literacy, visitation rate, preferences, recreational, health, and restorative benefits, vegetation characteristics, nature connectedness, and conservation support. The paper also proposes a framework for understanding biodiversity perception in urban green spaces that can assist in improving our understanding of the relationship between human interactions and natural environments and framing strategies for urban development, landscape planning, and community health promotions.


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