Antarctic sea ice is a sensitive factor to global climate changing. Study the sea ice changing laws is useful to choose the safe routes for the scientific investigation and merchant ships. South Shetland Islands adjacent sea is an important krill fishing area, it could be beneficial to choose the suitable days and routes to know the sea ice distribution and moving features in fishing seasons in advance. SAR data has the advantage of better penetrating ability than visible and infrared bands remote sensing data, they are more suitable to detect Antarctic sea ice than optical remote sensing data. A series of imagery pre-processing steps were carried out, including heat noise removing, radiometric calibration, speckle filtering, geo-coding, projection transformation, subarea clipping. Threshold method was carried out to detect sea ice, and 24 sea ice distribution maps were gotten from December 2015 to February 2016. Then sea ice concentration were calculated based on the sea ice extraction results maps, and sea ice changing law were analyzed in the South Shetland Islands adjacent sea area. Multi-polarization SAR data is more beneficial to improve the sea ice detection accuracy in the Antarctic sea area.
In this paper, a method which vectorizes and visualizes of 3-d terrain based on the contour line map using R2V and ArcGIS software is discussed. This method makes digitization and visualization easier, faster and more applicable. These data of contour line being vectorized and edited by R2V was imported into ArcGIS , finally the processed datum displayed in three-dimention manner. With the help of R2V and ArcGIS, digitizing of relief map and making DEM will be more effective and helpful for the technician in need.
Antarctic krill (Euphausia superba Dana), one of the resources which have never been fished before, is full of development potential. The data of the ocean environment, generated from remote sensing, is the important parameter in analyzing the spatial and temporal distribution, the state of resource and the fishery work environment of Antarctic krill fishery. After downloading, extracting, clipping, registration, projection and calculation, we have got the information about the sea area and state data of Antarctic Krill fishery. Then we make the thematic map according to the data characteristic. From the distribution map of the 3 fishing areas in 2011, it is indicated that chlorophyll-a density is maximum in December and minimum in February. The sea surface temperature is maximum in February, and minimum in August. And the sea ice density is maximum in September and minimum in February. There are some differences in different season.
How to project remote sensing data on a surface determines the accuracy of the remote sensing data analysis results. The
dramatically increasing large scope of high resolution remote sensing imagery requires an effective data structure. In
recent years, a number of data structures for global geo-referenced data sets have been proposed based on regular, multiresolution
partitions of polyhedron, named as geodesic Discrete Global Grids (DGGs). The DGGs can be used to manage
global multi-resolution geospatial data effectively. Octahedral quaternary triangular mesh (O-QTM) is a common
discrete global grid. An effective method for analysis of remote sensing data is proposed in this paper. The remote
sensing data are transformed to image based on octahedral quaternary triangular mesh. Image overlay analysis is
On the basis of the equilateral octahedron in the sphere, the global is recursively subdivided. With level of subdivision increasing, subdivision speed will descend markedly. So for the deeper hierarchy of subdivision, local subdivision is chosen. After the sphere is divided, to display the proper area, the correct cells should be found. So when the specific region is showed, its central cell needs to be as initial search cell to find grid cells within a certain range, and then show. Grid cells after subdivided can not achieve the ideal that the cells have the equal area and the equal shape, which affects the effect of display and the accuracy of search. Through the analysis of cell distortion, it is known that the basic attributes of cells distribute according to a certain law. With level of subdivision increasing, the changes tend to be stable which ensures the reliability of the deeper levels subdivision.