This paper obtained the satellite information derived from 5 channels of AVHRR data, which correspond to the 80 meterologic stations in the north-west of China, and researched the relationship between SI(sandy Index) and visibility, wind speed based on radiative properties of sand particle. The intensity of sand storm is confirmed by the levels of SI, which form a quantitative method to research the sand storm. The result showed that this method is effective for monitoring sand storm intensity.
:There are primary desertification types in Wuwei city that are wind erosion, water erosion and grassland retrogress at middle and low mountain. Through geometrical and projection system transform,standard false color composite, spatial enhance to image, link with land use/cover type, establish interpret symbol of TM image, and to extract information of desertification. It use different model piece of ARC/INFO software adequately, to interpret image, and compile and edit map, and statistic all kind of desertification information data. The results showed that desertification is very severe in Wuwei city, and total desertified lands have 217.07hm2, and occupy 83.33% of total area, among them most is Minqin county.
Based on the Landsat 7 ETM+ data and ground truth data, this paper takes Ruoshui Valley in the Heihe Basin as the typical region, and selects the training size of land use/cover classification with the method of Spectral Angle Mapper(SAM). Comparing the classification image with the true sample data,the paper got the feasible method for the desertification classification. And the accuracy of classification was also analyzed by using confusion matrix and Kappa statistic. The results show that the SAM could be used to classify land types with the overall accuracy of 0.7796 and the Kappa coefficient of 0.7139.
The study area of this paper is Qinghai Lake, the largest salt lake in China, which lies in the northwest of Qinghai province. The data derived from TM image in 1986 and 2000. Based on Remote Sensing, GIS and Mathematical Statistics, we analyze quantity and spatial construction changes of the landuse types. We also discuss the influence of the land use changes on the Qinghai Lake' s environment. The result shows that the farmland, water area and residential area all increase by 5 930.82 hm2, 2 218.75 hm2 and 382.69 hm2respectively. But the forest land, grassland and un-used land decreased by 7 542.64 hm2,894.34 hm2and 95.28 hm2respectively. In the decreasing part of the grassland, 6 266.56 hm2grassland area changed into cultivated land and 601.40 hm2grassland area changed into sand.
Each channel property of the MODIS image was analyzed for fire monitoring in this paper. In this year, the several forest fires occurred in Da Hinggan Ling Mountains and foreign regions were detected successfully by using infrared channel detecting and three-channel composite methods based on the MODIS data. The results show that we can get good effects when the 21st channel is used to be the channel for fire monitoring by using infrared channel detecting method. When the three-channel composite method is used,there is remarkable color difference between fire area and around area. So the forest fire can be detected fast and the trend of the forest fire can be estimated.
The objective of this paper is to study desertification of Gansu province. Two periods of Lnadsat TM images in 1986 and 2000 are used in our research. The desertification change is calculated for these two periods. We use two indexes, desertification scale and desertification degree, to quantify the desertification spatial pattern. The results show that Gansu province desertification has regional differential between eastern region and western region. The dividing point is Lanzhou. In detail, the desertification scale of the western region is bigger than that of the eastern region. By contrast, the desertification degree of the eastern region is higher than that of the western region. The activation of the fixed and semi-fixed sands is the main desertification source in both of these two regions.
In this paper, in order that the decennary change with riverhead conservation forest of upper reaches of Heihe river in Qi Lian mountainous area could be realized, the classification between coniferous forest and shrubbery based on TM data were achieved in this typical area. First of all, the TM data were preprocessed by geometrical correction and projection transform. Then, the composite color image was created by using 432 channels of TM data. The ground investigation was also achieved. The distinction and interpretation symbol was founded. Based on the result mentioned above, the classification between coniferous forest and shrubbery was successfully achieved in Qi Lian mountainous area by means of decision tree method. At last, the result of classification was verified.
Satellite remote sensing has become one of the important tools to survey land erosion. Take Zhungeer county as an example, depend on remote sensing images and other data, utilizing GIS software contained ARC/INFO and remote sensing software ERDAS, after disposition, transition of pattern and query, interpretation, the study achieve the soil erosion data of the area. The result shows that in Zhungeer county the hydraulic and eolian soil erosion of is serious and the hydraulic soil erosion is dominant. Waterpower and wind power erosion accounting for 68.39% and 48.45% respectively. So constructing protective-forest and returning land for farming to forest and grass are the key measures to prevent soil erosion.
The central part of Gansu province is chosen as the study region because it is the main region for environmental amendatory projects in the province. Ecological environmental background data were got from the interpreting for Landsat TM image in 1990, and the actual data were retrieved from the same type of image in 2000. Assisted by digital terrain model and fieldwork results, the environment of this region can be monitored dynamically. The results show that although some steps including returning farmland to forest, integrated harnessing in small catchments were carried out, the environment still tends to deterioration. The reasons for environmental changing in the past 10 year from 1990 to 2000 were analyzed. Corresponding suggestions were also listed out.
Wuwei lies in the temperate zone with typical desertified climate, which land types have sandy in oasis margins, saline and alkaline in downriver district and grassland degradation at mid and low mountains. Remote sensing, GIS and GPS were used to design desertification monitoring system in Wuwei. The system takes vector data as major data resources to construct management system of desertified spatial data, which meets the demand for mid and large scale desertified dynamic monitoring. The system includes data collecting and inputting, remote sensing processing and classification maps, spatial data management and result outputting. At last, this paper provides the methods for determining desertification and types,desertified information extraction from remote sensing images, desertification assessment of sloping cultivated land based on DEM.
Water and soil resources in Shule River Basin were exploited widely based on the execution of integrated agricultural development and immigrant allocation project in the basin. Meanwhile, there are some serious hydro-environmental problems such as wetland shrinking, vegetation degradation, land desertification and salification. Establishing a scientific, reliable and operational water resources managing and decision-making supporting information system is a basement for balancing the ecological environment, society and economic benefit and ensuring sustainable development of the regional economy. Initial studies for the structure, function and implementation of the system were done by analyzing the system requirement. It shows that the system should be based on the hardware, software and water resources data,and supported by Remote Sensing, GIS and GPS technologies and special models for water resource management. And it should consist of data collecting, transmitting, saving, managing, analyzing, decisionmaking supporting, inputting and system were outputting for purpose of assessment, management and decision-making support in Shule River Basin.
Geographic Information System for Transportation(GIS-T) has been widely used in the designing and management of roads network and other facilities. In this paper the types, methodologies, data models and spatial analysis of GIS-T are introduced in detail. The principle based on arc-node topological relation and dynamic segment are expatiated by a development instance. Some problems, such as building rich query, the mileage mark system and the road descriptive system, are also discussed by a sample of GIS-T for Northwestern China. The application instance of GIS-T showed that it would greatly improve the convenience and efficiency of the transportation vocation.
The paper offered some methods for establishing city three-dimension model and spatial information system by using three-dimension COM technologies. The aim is to construct city spatial GIS projectdigital city. Furthermore, combined with the new digital surveying technology, the paper also introduces the flow to set up city spatial GIS.
This paper applies the Visual GIS technology to the flying simulation of digital river basin. It is a case of the Heihe River Basin. During the period of pre-processing the data, The mosaic image of the Heie River Basin is mapped by six Landsat ETM+ images and five Landsat TM images. All the images are geometrically co-registrated by using 1:100,000 scale topographical maps. The contour lines are digitized from one hundred and fifteen pieces of 1∶100,000 scale topographical maps. Then they are interpolated by using the ArcView Spatial Analysis for the TIN model. At last the TIN model is translated into GRID forat DEM. The Visual GIS module of the ERDAS IMAGINE is used to make the Heihe River Basin flying simulation. The data of DEM, mosaiced image and vector layers are integrated as the base data. The flyng parameters are setup by the man-machine interactive way. By using flying views, the user can undertand the landscape and detail information of the terrain, physiognomy and vegetation cover much more viually and vividly than by viewing the digital mosaiced image.
Gansu province lies in the western China. The western development brings the chance of economic development to Gansu province. It' s very important that how to make the economical, environmental,social development sustainable, and establish a strong maneuverable index system. This paper uses GIS technology to study the sustainable development of Gansu province, by breaking the boum of administration cell and reflecting its spatial-distributed law. Then spatial structure optimization of sustainable development could be achieved. Based on the analytic and statistic function of GIS software , the sustainable development indexes can be computed.
It is a new method to estimate land surface evapotranspiration of large region by using remote sensing. This paper analyzes several remote sensing models of land surface evapotranspiration such as Land Surface Energy Balance, Complementary Relationship of Land Surface Evapotranspiration, PenmanMontieth and Climatology Method of Regional Evapotranspiration. Methods to derive land surface parameters from remote sensing data are given. The paper meteres include Albedo, NDVI, Surface temperature and Emissivity, which are used widely at home and abroad. The relationship among them are delineated.
The general criteria used to distinguish the boundary of frozen/thaw soil are the 37GHz radiobrightness and negative spectral gradient. This paper concerns the research of distinguishing the boundary of frozen/thaw soil using passive microwave remote sensing data and discusses the algorithm development and research trend. It' s very important to develop reliable and applied algorithms to distinguish the frozen/thaw boundary and to provide the soil information of regional and global scale for research and application of hydrology, meteorology, agriculture, engineering and geology.
The National Aeronautics and Space Administration puts forward and coordinates the Earth Science Enterprise (ESE). This paper introduces the ESE' s strategic missions, study objectives, collaborators and relative earth science projects. The key aim of ESE is to study the interaction of each system interior by the data attained by a series of satellites and to research global change comprehensively and reliably.
According to an example, this paper introduces a technical procedure to update the base-map of landuse. First, some raster and vector data (such as remote sensing images, landuse investigation vector data, and changed map-patches obtained by computer assistant tool) were overlapped in a same layer.Then, the various information were retrieved in the interaction process, and topology relations were set up based on the changed map-patches layer. Supported by the GIS, changed map-patches layer was modified and compiled, and the topology relations were built. Finally, using the GIS vector overlay function, the changed map-patches layer was overlapped and calculated with detailed database to create the landuse database files.
The study content of this paper is the remote sensing survey of the soil conservation in the part of Yellow River Basin in Gansu province. Six main influential factors are analyzed. They are erosion types,erosion intensities, land surface components, topographic types, vegetation covers. To analyze the distributing shape, texture and identification features of these factors in the Landsat TM images, the information extraction methods of these factors from remote sensing interpretation are discussed. An application is used on the digital works of the Remote Sensing survey in the part of Yellow River Basin in Gansu.
The fusion images of TM and SPOT data were used in the study of land use and land cover of Dingxi county between 2000 and 2001. The changes of land use structure, especially those of cropland reforested and regrassed slope in the last year were analyzed to estimate the changes of environment of this county. Investigation and survey of regional environment was realized preliminary. Some feasible methods were put forward for investigation and dynamic monitoring of environment and reforesting and regrassing in loess plateau.
The aerial remote sensing image has the advantage of high resolution, while the TM image has the predominance of multi-spectral information. This paper introduces the theory and method of the fusion of aerial and TM images, and discusses the application of fusion image to make three-dimensional landscape graph, inundate analysis and loss evaluation, monitoring the conditions of reforesting and regrassing, boundary survey and virtual-reality simulation system.
The soil erosion of the Yellow River Basin in Gansu is very serious. The main type is water erosion. The frozen-thaw erosion and wind erosion just distribute in part of regions. The main driving factors are natural factors and manmade factors. The natural factors include loose structure of the regional soil,centralized rainfall with higher slope, bad vegetation cover in the most of regions. The manmade factors include reclamating the waste land with high slope which meets the increasing population, over-grazing,forest-destroying and developing and constructing projects.
