Abstract
During the last few decades, a large number of people have migrated to Kathmandu city from all parts of Nepal, resulting in rapid expansion of the city. The unplanned and accelerated growth is causing many environmental and population management issues. To manage urban growth efficiently, the city authorities need a means to be able to monitor urban expansion regularly. In this study, we introduced a novel approach to automatically detect urban expansion by leveraging state-of-the-art cloud computing technologies using the Google Earth Engine (GEE) platform. We proposed a new index named Normalized Difference and Distance Built-up Index (NDDBI) for identifying built-up areas by combining the LandSat-derived vegetation index with distances from the nearest roads and buildings analysed from OpenStreetMap (OSM). We also focused on logical consistencies of land-cover change to remove unreasonable transitions supported by the repeat photography. Our analysis of the historical urban growth patterns between 2000 and 2018 shows that the settlement areas were increased from 63.68 sq km in 2000 to 148.53 sq km in 2018. The overall accuracy of mapping the newly-built areas of urban expansion was 94.33%. We have demonstrated that the methodology and data generated in the study can be replicated to easily map built-up areas and support quicker and more efficient land management and land-use planning in rapidly growing cities worldwide.
Highlights
Worldover, cities function to compactly cluster populations and support a high degree of economic activity [1]
We propose the use of the metric Normalized Difference and Distance Built-up Index (NDDBI) generated using Normalized difference vegetation index (NDVI) and the distance to roads and buildings represented in OpenStreetMap (OSM)
The plotted graph shows that there was generally a significant drop in NDVI values associated with the conversion from other land cover types into built-up areas
Summary
Cities function to compactly cluster populations and support a high degree of economic activity [1]. Over the past 30 years, built area expansion has been outpacing urban population growth, suggesting that cities are becoming less compact rates [3,4]. Most of this growth is expected to occur in small and medium-sized cities, not in mega-cities [5]. The reasons for these migrations are multi-fold and include the lure of reliable food and infrastructure, and a perception of increased economic opportunities, prosperity, and security
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.