Estimating the Soil Copper Content of Urban Land in a Megacity Using Piecewise Spectral Pretreatment

Yi Liu, Tiezhu Shi (), Zeying Lan, Kai Guo, Dachang Zhuang, Xiangyang Zhang, Xiaojin Liang, Tianqi Qiu, Shengfei Zhang and Yiyun Chen
Additional contact information
Yi Liu: School of Public Administration, Guangdong University of Finance & Economics, Guangzhou 510320, China
Tiezhu Shi: State Key Laboratory of Subtropical Building and Urban Science & Guangdong–Hong Kong-Macau Joint Laboratory for Smart Cities & MNR Key Laboratory for Geo-Environmental Monitoring of Great Bay Area, Shenzhen University, Shenzhen 518060, China
Zeying Lan: School of Management, Guangdong University of Technology, Guangzhou 510520, China
Kai Guo: School of Geography and Remote Sensing, Guangzhou University, Guangzhou 510006, China
Dachang Zhuang: School of Public Administration, Guangdong University of Finance & Economics, Guangzhou 510320, China
Xiangyang Zhang: School of Public Administration, Guangdong University of Finance & Economics, Guangzhou 510320, China
Xiaojin Liang: Guangzhou Urban Planning & Design Survey Research Institute Co., Ltd., Guangzhou 510030, China
Tianqi Qiu: Guangzhou Urban Planning & Design Survey Research Institute Co., Ltd., Guangzhou 510030, China
Shengfei Zhang: School of Public Administration, Guangdong University of Finance & Economics, Guangzhou 510320, China
Yiyun Chen: School of Resource and Environmental Science & Key Laboratory of Geographic Information System of the Ministry of Education, Wuhan University, Wuhan 430079, China

Land, 2024, vol. 13, issue 4, 1-21

Abstract: Heavy mental contamination in urban land is a serious environmental issue for large cities. Visible and near-infrared spectroscopy has been rapidly developed as a new method for estimating copper (Cu) levels, which is one of the heavy metals. Spectral pretreatment is essential for reducing noise and enhancing analysis. In the traditional method, the entire spectrum is uniformly pretreated. However, in reality, the influence of pretreatment on the spectrum may vary depending on the wavelengths. Limited research has been conducted on breaking down the entire spectrum into distinct parts for individualized pretreatment, an innovative method called piecewise pretreatment. This study gathered 250 topsoil samples (0–20 cm) in Shenzhen City, southwest China, and obtained their vis-NIR spectra (350–2500 nm) in the laboratory. This study divided the spectrum into three parts, each processed by six commonly used spectral pretreatments. The number of pretreated parts varied from 1 to 3, resulting in 342 PLSR models being built. Compared to the traditional method, piecewise pretreatment showed an increase in mean residual predictive deviation (RPD) from 1.55 to 1.71 and an increase in the percentage of positive outcomes in ∆RPD from 33.33% to 55.56%. Thus, we concluded that piecewise pretreatment generally outperforms the traditional method. Furthermore, piecewise pretreatment aims to choose the most effective pretreatment method for each part to optimize the Cu estimation model.

Keywords: urban land; spectral pretreatment; heavy metals; Cu (copper) (search for similar items in EconPapers)
JEL-codes: Q15 Q2 Q24 Q28 Q5 R14 R52 (search for similar items in EconPapers)
Date: 2024
References: View references in EconPapers View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2073-445X/13/4/517/pdf (application/pdf)
https://www.mdpi.com/2073-445X/13/4/517/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jlands:v:13:y:2024:i:4:p:517-:d:1375453

Access Statistics for this article

Land is currently edited by Ms. Carol Ma

More articles in Land from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().