珞珈一号夜间灯光影像中国城市建成区提取能力综合评估

Comprehensive evaluation of the urban built-up areas mapping ability from Luojia 1-01 nighttime light imagery over China

城市建成区是人类活动的物理空间,是监测城市化进程的重要指标,而夜间灯光影像是一种有效的城市建成区制图数据源。作为全球首颗专业夜间灯光遥感卫星,珞珈一号(LJ1)比可见光红外成像辐射仪NPP/VIIRS(NPP)的空间分辨率更高。目前关于珞珈一号城市建成区提取的研究尺度有限,缺乏系统性的大尺度评估。本文以NPP的表现为基准,首次评估珞珈一号在中国不同气候带及发展规模的城市建成区提取能力,并讨论集成LJ1和NPP两类夜灯数据的潜力。结果显示:一方面,LJ1百米制图结果的查全率一般都低于灯光溢出更明显的NPP;另一方面,得益于LJ1更高的空间分辨率和细节捕捉能力,除小城市外,LJ1提取结果的查准率均高于NPP。从F 1值来看,LJ1只在超大/大城市可取得优于NPP的表现。当制图分辨率为500 m时,LJ1的F 1值基本都低于NPP。两个分辨率的城市建成区制图结果均表明珞珈一号和NPP/VIIRS的联合利用优于单一夜灯影像。

The urban built-up areas are physical spaces for human activities,which is a critical indicator for monitoring the progress of urbanization.Furthermore,nighttime light imagery is an effective data source for mapping urban built-up areas(BUA).LJ1-01(hereinafter referred to as LJ1),the first global professional nighttime light(NTL)remote sensing satellite,has a finer resolution than the Visible Infrared Imaging Radiometer Suite(VIIRS)sensor on the Suomi National Polar-orbiting Partnership(NPP)satellite.Currently,studies focusing on the BUA extraction from LJ1 are limited in spatial coverage and lack of systematic large-scale evaluation.This study aims at achieving the first assessment of LJ1 for urban BUA mapping over China,including multiple biomes and city levels,with the results of NPP as comparisons.In addition,the performance of integrating both NTL datasets(LJ1 and NPP)is also discussed.The results show that LJ1 achieves lower recall ratio than NPP(that suffers from an enhanced blooming effect)at the 100 m resolution,while the precision of LJ1 is higher than that of NPP except for the small cities,owing to the higher spatial resolution of LJ1 and its capability in capturing more spatial details.As for F 1 score,LJ1 performs worse than NPP except in mega/large cities.At the resolution of 500 m,the F 1 of LJ1 is generally lower than that of NPP.The results at both resolution levels demonstrate that the combined utilization of LJ1 and NPP outperforms their individual use in the urban BUA extraction.