The purpose of using unmanned aerial vehicle (UAV) remote sensing application in Five-hundred-meter aperture spherical telescope (FAST) project is to dynamically record the construction process with high resolution image, monitor the environmental impact, and provide services for local environmental protection and the reserve immigrants. This paper introduces the use of UAV remote sensing system and the course design and implementation for the FAST site. Through the analysis of the time series data, we found that: (1) since the year 2012, the project has been widely carried out; (2) till 2013, the internal project begun to take shape;(3) engineering excavation scope was kept stable in 2014, and the initial scale of the FAST engineering construction has emerged as in the meantime, the vegetation recovery went well on the bare soil area; (4) in 2015, none environmental problems caused by engineering construction and other engineering geological disaster were found in the work area through the image interpretation of UAV images. This paper also suggested that the UAV technology need some improvements to fulfill the requirements of surveying and mapping specification., including a new data acquisition and processing measures assigned with the background of highly diverse elevation, usage of telephoto camera, hierarchical photography with different flying height, and adjustment with terrain using the joint empty three settlement method.
The study investigated wetland change in Wanning. For this purpose, three high resolution SPOT images recorded in 2002, 2007 and 2013, respectively, were classified. The results indicated that there were little change in wetland types during 2002 and 2013. The coastal waters, culture pond and river were the main wetland types. The natural wetland trended to decline. The ditch had the largest net increase and the reservoir shrank the most. There was a dramatic increase of culture pond plaques, which making the landscape more fragmentized. The coastal waters and the land had a lot change with other wetland types. The area change in Wanning was mainly composed of the transition between the land and culture pond.
Statistical methods to map water depth from medium-high resolution multispectral images were easier and more popular than wave spectrum bathymetry or water scattering-based implementation. However, less studies compared the effectiveness of the popular statistical methods for pelagic islands. This study used the Log ratio transform, primary component analysis and independent component analysis methods to retrieve water depth of Pratas Island,using one Landsat 8 Operational Land Imager (OLI) image. Results showed that the Log ratio transformation was not the best method as the proposer suggested. The first primary component and the second independent component are good predictors for absolute water depth ranging from 0 to 20m, while Log Ratio was more sensitive to water depth ranging from 0 to 5m, IC2 was sensitive to water depth between 5 and 10 m.