The Urban heat island (UHI) effect has been increasing so prominently that the measures for quantitative monitoring, analysis and evaluation of the UHI effect have become one of the most important fields in current urban climate and environment researches. This paper deals systematically with data sources, methods and results of applying remote sensing to the study of urban heat island, and gives a detailed review of researches on UHI conducted by experts all over the world in such aspects as its thermal pattern, process change regularity and causes. On such a basis, the paper predicts the development trend of applying remote sensing to studying urban heat island in future.
With the rapid urbanization, problems caused by heat-island effect have become more and more serious. It is necessary to make rapid and effective monitoring of the distribution of heat islands in cities. In this paper, the Landsat7 ETM+ image of Nanjing was investigated as an example. A correlation model was built between ground temperature and image brightness of TM6, and in this way, the distribution of temperatures in Nanjing was obtained. The urban vegetation can be classified into forest, interspersed tree and herbaceous plant based on the NDVI value. At the same time, the other ground objects can be classified by supervised classification. In addition, the authors probed into the correlation coefficient between the ground covers and the temperature distribution from the angle of fragmentation degree. It can be concluded that different fragmentation degrees of urban greening exert different effects on the temperature of ground surface.
AMSR and MODIS are two EOS (Earth Observing System) instruments in Aqua satellite. A regression analysis between the brightness of all AMSR bands and the MODIS land surface temperature product provided by NASA indicates good correlation, and hence retrieving land surface temperature from AMSR passive data is available without ground true data (soil moisture and land surface type). The analytical results in such regions as North Africa, Northeast China, Tibet China and India indicate that the radiation mechanism of snow-covered surface is different from mechanism of other conditions. In order to retrieve land surface temperature more accurately, we can classify the land surface at least into two groups. For land surface covered with no snow, the average land surface temperature error is about 2℃ relative to the MODIS LST product. For snow-covered land surface, the average land surface temperature error is about 2~3℃ relative to the MODIS LST product. Besides, the emissivity of passive microwave is a very important parameter for retrieving soil moisture. The authors computed the emissivity through land surface temperature retrieved by the statistical regression method and made an analysis.
This paper describes and tests three kinds of transform algorithms for remote sensing image rectification. A comparison with results from PCI commercial remote sensing software shows that the Givens transform algorithm is on the whole superior to other algorithms in precision in 1~5 order multinomial rectification.
Simplification of triangulation structure plays an important role in constructing three-dimensional models. The authors studied all currently-used triangulation-simplification algorithms and applied a very useful algorithm named TIN simplification based on Vertex Decimation to actual simplification of the three-dimensional terrain. Considering the huge quantities of data from the three-dimensional terrain, the authors made some improvement on this algorithm so as to render it more efficient. The simplified modeling using the improved algorithm simplification has the same error as the original algorithm.
In data processing, data are usually obtained through coordinate conversion. The cadastral parcel is one of the most important objects, and the area of a parcel is the key attribute with legal authorization. However, the parcel area based on the conversion data is different from the original area. In this paper, the authors have developed a relational equation of area computation with coordinate conversion parameters, which is a simple and convenient method for area computation. Theoretical analysis and case studies show the correctness of the equation of area calculation with coordinate conversion parameters. It is concluded that the area conversion parameters in area adjustment are easier to be detected and hence the scheme of the coordinate conversion can be selected correctly.
Aimed at tackling the problem of data conversion in urban GIS exploitation, this paper puts forward the data conversion technique from MapGIS to ArcSDE. By comparing the difference and commonness between MapGIS and ArcSDE, this paper proposes using filtration to covert point and polygon information and using symbol comparison table to covert the symbols of two GIS softwares. This method can meet the need of urban GIS exploitation.
This paper analyzes the limitation of traditional edge detection methods in the use of multispectral images, and proposes an edge detection technique based on spectral space analysis of local area whose average radius can be calculated. This method expands the previous concept of edge detection of the single image and, because of the transformation from the gray value to the gray vector and the consideration of multi-scale combination, can acquire satisfying results.
This paper describes in brief the capabilities and design of HDF 5 (Hierarchy Data Format), such as its structure which is hierarchical in logic and B-Tree in physics, its advantage in straightforward implementation and self-description means of sharing science data among people, projects and types of computers, and its object-oriented specificity. The standardization of remote sensing data can benefit from these characteristics.
There are two kinds of spatial relations between remote sensing ore-searching information and geochemical anomalies, i.e., overlap and coupling. With the fusion processing of data, their correlation can be recognized and judged accurately so as to find the composite ore-prospecting target. On the basis of such idea, the fusion processing methods and the application of remote sensing data and geochemical data are studied in the research area of East Tianshan Mountains.
Using seismic materials on the basis of GIS, this paper has made an integrated analysis of the gravity, magnetism, electricity and remote sensing data obtained from Aktobe area in Kazakhstan. As most of carbonate oil reservoirs already found in this area are fracture porosity reservoirs, a study of the distribution of small faults and fractures on the basis of remote sensing will contribute to the improvement of water injection efficiency. The study can play an important role in controlling well patterns, providing accurate well location coordinates and investigating ground facilities in such oil fields as Zhanazhol and Alibekmola.
Based on data fusion between landset-7 ETM+ pan band and multispectral bands and RGB synthesis, the authors analyzed the surface rock images and linear and ring images of Xiangshan area, and interpreted five linear fractures, namely NE, NNW, NWW, SN, and EW trending faults. The reactivation of NE trending fault No.F2 in Quaternary led to the subsidence of the northwestern part relative to the southeastern part in the Xiangshan ore field, forming two special image areas, namely the southeastern image area and the northwestern image area. The former is a archibole and has experienced a relative intense denudation, whereas the latter is a target area for uranium ore exploration.
Using Landsat ETM data, the authors applied remote sensing to geological mapping. First, the image
processing (using ER Mapper 6.2 platform) mainly based on the principal component analysis, RGB-HSI-RGB
transformation and false-color composition was adjusted according to several geological sections in the working area
in order that the major lithological units could be distinguished from each other on the image. Then ETM Pan as well
as the 15 m resolution band was used for promoting some final images to 1︰50,000 scale through data fusion.
Moreover, geological mapping was carried out by using ARCVIEW 3.0 a platform on the basis of the images and in the
light of the cross section studies and all of the known facts. Certain lithological boundaries and faults were
selected to be inspected in site and the image processing was adjusted again to the inspection result. In the end,
the geological map was fulfilled through the final modification based on the further processed images, general
analyses and editing on the ArcInfo 7.1.1 platform. Field examination shows that this geological mapping method
using remote sensing is accurate and suitable to the areas characterized by limited vegetation and soils as well as
tough topography.
Using 1986 and 2000 remote sensing data as the basic information resource and with the support of GIS,
the authors built up a wetland spatial information dataset. On such a basis, the changes of wetland resources in
this area were analyzed, and the reason for such changes was investigated. The area of farmland as well as shrimp
and crab pools increased rapidly while that of swamp and shoal land decreased significantly in 15 years. The changes
of wetland in this area were closely related to climate fluctuation, rapid growth of population and development of
industry and agriculture, with the social-economic factors being most important.
This paper reports the achievement of a knowledge innovation project of GIS named the spatial-termporal
information analysis of terrestrial environment by remote sensing in combination with pre-research of relative
theory and the technique of digital earth. The classification of the water-level fluctuating zone of Three Gorges
Reservoir aims to provide a theoretical basis and scientific methods for rational development, utilization and
management of the water-level fluctuating zone by local government and administration department.
The authors examined the capability of reflectance spectroscopy for drill core logging in the Yanzhuang
magnetite-quartzite type iron deposit of Changli county, Hebei province. 261 rock samples were collected for
chemical analysis and spectral measurement. The results show that the reflectance of iron ore is low, generally
between 5%~20%. The absorption band of iron ion is in the range of 400~1100 nm. The content of iron shows
significant negative exponent correlation with the average reflectance of 850~900 nm, and this provides a
theoretical and technical basis for hyperspectral drill core logging in this kind of ore deposits.
Internationally,the building of the standardized spectral library in remote sensing has already
developed towards network share since 1990’s. As a reform and opening window in China, Guangdong province urgently
needs building up a standardized crop spectral library, especially in featured crops of South China, for stepping up
the agricultural information level. This research focused on the organization of spectral data and the construction
of a database system for featured crops of Guangdong province. The database is composed of five parts, i.e., the
knowledge database, the library for measured spectra, the remote sensing model database, the spectral analysis and
the application demonstration for the litchi orchard. In the spectral analysis, the authors designed and provided
the query of spectral data, the uploading of remote sensing images, and the analysis and simulation of spectral
data. The spectra-based planting area monitoring demonstration of the litchi orchard is presented so that the users
can utilize the spectral library conveniently.