The high spatial resolution and temporal observation frequency of HJ-1/CCD make it suitable for aerosol monitoring.However,because of the lack of a shortwave infrared band,it is difficult to use HJ-1/CCD imagery to retrieve aerosol optical depth(AOD).We developed a new algorithm for HJ-1/CCD AOD retrieval by introducing MODIS surface reflectance outputs(MOD09) as support.In this algorithm HJ-1/CCD blue band surface reflectance was retrieved through MOD09 blue band surface reflectance by band matching of the two sensors.AOD at 550 nm was then generated through a pre-calculated look-up table for HJ-1/CCD.Eighteen HJ-1/CCD images covering the Jing-Jin-Tang(Beijing-Tianjin-Tangshan) region were used to retrieve AOD using the new algorithm,and the AODs were then validated using AERONET ground measurements in Beijing and Xianghe.The validation shows that compared with AERONET ground measurements,27/29 AODs have error less than 0.1 in absolute value.
SUN Lin1,2,SUN ChangKui1,LIU QinHuo2 & ZHONG Bo2 1Geomatics College,Shandong University of Science and Technology,Qingdao 266510,China
传统的基于ArcGIS API for Flex的数字校园系统存在以下几个问题:(1)在目标定位时,只定位到目标建筑物几何中心位置,对建筑物内部具体单元定位精度不够;(2)管理者更新、维护空间数据须结合地图编辑软件和ArcGIS Server来实现,给数据维护造成不便;(3)360度实景导航技术在数字校园中的引入已成为研究热点,而大量实景数据必然增加了系统负担,降低加载速度。本文提出采用精确地理定位网的方法,即在处理线状道路数据时,暂不考虑真实目标之间的位置关系,细化原线状矢量层,并与其他网络分析图层分别保存,使得定位更加精确;以新版ArcGIS的Feature Access,采用ArcGIS API for Flex在线编辑工具进行在线编辑地图;将360度实景数据在服务器上管理,生成实景链接地址,在程序运行时只需调用该链接。本文以某高校数字校园系统为例,验证了精确地理定位网方法、实景数据的单独管理,以及在线地图编辑的可行性与有效性。
