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Analysis of urban green spaces using geospatial techniques- a case study of Vijayawada urban local body, Andhra Pradesh, India

Student name: Ms Priyal Bhatia
Guide: Dr Nithiyanandam Yogeswaran
Year of completion: 2021
Host Organisation: Andhra Pradesh Space Applications Centre (APSAC)
Supervisor (Host Organisation): Dr Vani Timmapuram

In the past, urban green space was regarded as one of the most important aspects of a healthy city. However, with rapid urbanisation, urban sprawl, and population growth, there has been a sharp decline in open green spaces in cities, particularly in metropolitan areas. Also, over the last few decades, there has been a shift in land use and land cover, with a decrease in the area of green spaces, agricultural lands, and urban greenery. This study was carried out to assess green spaces in Vijayawada's Urban Local Body. Because of better economic opportunities, the city has seen a surge in population inflow. Furthermore, the city's outskirts are more vulnerable to transition due to the presence of the Krishna River. As a result of these factors, there has been a decrease in urban green spaces from 2012 to 2020. The total ratio of urban built-up (NDBI) has also spiked. For the year 2012, the total area accounted for by built-up was 25.38 square kilometres. However, in 2020, it has grown to 35.06 square kilometres. This has skewed per capita greenness of the city. It is only 16 sq m. at present. The results show that there exists a negative correlation of -0.46 between per capita green and population, therefore with every 1 unit increase of population, the demand for built up and urban amenities will increase, thereby, impacting the per capita green and overall greenness index of the city negatively. The study also compares the Normalized Difference Vegetation Index (NDVI) to the Transformed Difference Vegetation Index (TDVI). It is a new index that is not widely used. Because it does not saturate, TDVI has proven to be superior to NDVI for urban green analysis. NDVI shows vegetation of 21.25 sq km where as TDVI shows vegetation of 16 sq km. Not only this, there has been an increase of merely 2% of vegetation in past 8 years span. The study also aims at identifying areas which are suitable and available for expansion of urban green and open spaces. A total of 2618 sq m area has been identified for expansion of the same. Geospatial techniques have been used here for mapping, graphing and quantifying the changes from 2012 and 2020. Furthermore, remote sensing techniques and methods have been used for assessing the satellite data. The same shows that vegetation and wastelands had a high transition rate to built-up and other LULC classes. Apart from wastelands and vegetation, a total of 11% of transition from other LULC classes to built-up has been observed.

KEYWORDS: Urban Landscape NDBI, NDVI, TDVI, Urban Green Space, Site Suitability, Per Capita Greenery.