Identification of urban land use efficiency by indicator-SDG 11.3.1

TLDR

Rapid urbanization has led to inefficiencies in urban land use, and the UN SDG 11.3.1 indicator is designed to assess this efficiency. Using geospatial and statistical data from 1990 to 2015, the study extracted built‑up land in Wukang, Deqing County, China, validated the extraction with an error matrix, and applied the UN metadata model to compute SDG 11.3.1 land‑use efficiencies. The results show that Deqing County’s land‑use efficiency is below the global average, that urban land becomes denser with population growth—enhancing sustainability—and that the findings can guide local government in balancing land consumption and population growth.

Abstract

Inefficiency in urban land use is one of the problems caused by rapid urbanization. The UN Sustainable Development Goals (SDGs) indicator 11.3.1 is designed to test urban land use efficiency. This study employed geospatial and statistical data to compute land use efficiencies from 1990 to 2015 with five 5-year and ten 15-year intervals in Wukang, center of Deqing County, China. A flowchart was designed to extract the built-up lands from multiple data sources. The produced built-up lands were demonstrated to provide good accuracy by constructing an error matrix between the extracted and manually interpreted built-up lands as classified and reference images, respectively. By using the model provided by UN metadata to calculate SDG 11.3.1, the land use efficiencies from 1990 to 2015 were identified in Wukang. Our results indicate that the land use efficiency in Deqing County center is lower than the average of cities around the world, primarily because our in-situ study focused on a county center with larger rural regions than urban areas. Over the long term, urban land use becomes denser as the population grows, which will have a positive impact on the sustainability of urban development. This work is helpful for the local government to balance urban land consumption and population growth.