The effects of albedo on land surface radiation budget and regional and global climate wereanalyzed in this paper. Retrieving accurately land surface albedo by remote sensing data is the preconditionof other land surface parameters retrieval, so albedo is the first important parameter in land surfaceparameters retrieval by remote sensing data. On the basis of the concept of albedo and other terms oftenconfused were demonstrated, the steps and solutions to main difficulties of retrieving land surface albedoby remote sensing data were given and discussed briefly. At last, we analyzed the process of calculatingalbedo in present land surface process models and compared the results with the products related toMODIS. The integration of remote sensing and land surface process models and global climate models wasemphasized.
Considering the overestimation of snow depth in West China using the global algorithm, thegeographic region is divided into two parts by 105°E. The modified and global algorithms are used toretrieve the snow depth in West and East part, respectively. However, the retrieval of snow cover anddepth will be overestimated due to the influence of precipitation, cold desert, and frozen ground.Therefore, for setting up the operational scheme, a land surface type classification tree based on the SSM/I data has been used to remove these factors. In final, the MODIS snow products in 2000/2001 wintershave been collected for the assessment of accuracy from passive microwave remote sensing data. In theninety days, the means of overall accuracy and Kappa coefficient are 86% and 66%, respectively.
The Land-use Information Systems (LIS) with a scale of 1∶10 000 have been founded in manycounties and cities since newly soil resource investigate. This paper aimed to discuss the principle,method, technical flow and quality control of updating LIS data by using SPOT5 and bring forwardfeasible resolvent.Key Word: SPOT5, Land-Use Information System, update
The project of returning land for farming to forest and grassland aimed at control of soil andwater loss, improvement of fragilely ecological environment in West China. This paper exemplified GulangCounty with SPOT5 image in 9 September, 2003, and discussed orthorectification of SPOT5 andtechnologies and processing methods of true color composition by band calculation in lack of blue band,and expatiated on the accuracy evaluation before and after image correction. This paper further discussedthe application of processed SPOT5 images to the visualization of information of returning land for farmingand accurate monitoring.Key words:Remote sensing, SPOT5, Geometric correction, Band calculation, Returning land for farmingfor forest, Accurate monitoring, Visualization, Gulang county
Digital elevation models (DEMs) are important tools to model the process of modernenvironment, and the ones with high precision become a key content to construct distributed modernprocess models. Based on the two drainage structure orders from Shreve and Strahler, the techniquesextracting channel network based on GRID are developed and used in Qaidam basin by employing severaldifferent DEMs based on the digitized contours of 1∶250 000 and 1∶100 000 of Qaidam basin. Bycomparison, the spline interpolation method on contours has better effects; when computing the flowrouting matrices the grid size will affect the results significantly, especially in complex landform areas; andthe best effect of delineation can be obtained by choosing the mean value of the accumulative matricesabout the whole watershed as the calculated threshold extracting watershed network.
It is widely recognized that population data are very important to integrate research among thehuman beings and environmental factors in global, continental and regional scales. But the populationcensus data collected based on the administrative units do not match the environmental data collected basedon the natural units. So studies on the population spatial distribution are necessary by modeling andestimating the population data. The basic method of the population estimation is linking population datawith geographical variables. Remote Sensing and Geographic System Information (GIS) are the mosteffective research tools. The advance in population spatial distribution during the last two decades based onthe Remote Sensing and GIS was introduced by presenting international and internal population spatialdistribution projects and methods. Then the typical population estimation results of GPW, UNEP/GRID,LandScan and Chinese 1 kilometer population data were compared and analyzed in a case of Heihe RiverBasin with the registration statistics data provided by the government. The results show there are a lot ofstudy works developed by the international and internal organizations and researchers. Internationalresearches mainly include population estimation from the land cover data, DMSP-OLS night light data orspectrum information directly afforded by the Remote Sensing images. Chinese researchers also make manydistinguished works in despite of the later starting. Construction the regression correlation among thepopulation data with land use data and other geographical factors (e.g. elevation, road, and residentialarea) is the most used method for these works. The comparing results show Chinese 1 kilometerpopulation data has the best estimation accuracy for the Heihe River Basin population spatial distribution.Key words:
An area located among of 98.5～102.5E and 31～33.65N with 49117.9 km2, part of the WestSichuan Plateau, also part of the upper reaches of the Yangtze River and the West Engineering of WaterTransfer from South to North China, was studied in the paper. The TM and ETM+ images (1995,1999) were interpreted with the information resources of relief maps, by using the techniques of remotesensing, the geographical information system, the information extracting means of field investigation andthe interpretation on the computer screen. And the database of land cover/land use and the land type ofthis area were also established. The database includes the TM image database, the digital relief mapsdatabase, the land cover/land use database (1∶100 000) and its attributing database. The results showthat the types of high-cold meadow with high coverage, high-cold shrub meadow, high-forest and shrubforest , with the 84.14% of the total area ,are the main types in the test area. The spatial distribution ofland cover/use show that: first, the region with altitude above 4 600 m a.s.l. in this area is usual adividing ridge, where the vegetation is mainly high-cold meadow with low coverage; second, the regionwith altitude of 4 000～4 600 m a.s.l. is the main part of this area, where the vegetation is mainly high-cold meadow with high coverage, and high-cold steppe with low coverage; third, 40% of this area withaltitude of 2 800～4 000 m a.s.l., where the vegetation is mainly high-cold steppe with high coverage, andpart of high-cold shrub meadow, high-cold swamp meadow and shrub forest in the area with high moisturecontent; last, the area with altitude below 2800m a.s.l. is covered with by high-cold steppe, shrub forestand forest land. These results will provide the data for studying the hydrological characteristics of thisarea.
The oasis distribution maps of six typical years were made using aerial photo in 1959, MSS imagein 1973 and TM images in 1987, 1994, 1998, 2001 by combining visual interpretation and automaticclassification method. The distribution and area change data of desert reclamation in Minqin Basin duringlast 40 years were obtained by overlay analysis and area statistic in GIS. The result indicates the desertreclamation in Minqin Basin developed rapidly, especially in 1970s and 1990s. The two extending modes ofdesert reclamation are the extend of oasis“Pizza”and extend to the desert hinterland jumpily. Theextending of desert reclamation is attributed to the early policy of“The most importance thing iscommissariat”and lately entironment deterioration of oasis and derive of economic benefit. The rapiddevelopment of desert reclamation have badly damaged the periphery entironment of oasis and acceleratedthe desertification.
this paper, the application effect of CBERS-1 data in desertification monitoring in NorthwestChina was analyzed and evaluated. The wavelength scopes of ban 2,3 and 4 of CBERS-1 data were similarto the same bands of TM data, so it was comparable with TM data. CBERS-1 composition images clearerdisplayed features of ground objects than TM images because of its higher spatial resolution compared withTM data. The results showed that CAERS-1 data may be applied to landuse mapping and desertificationmonitoring in desertified regions after deterministic processing. There had some speckles or stripe noises ineach single band that can be partially reduced by noise-filtrating processing, and the displacements that canbe eliminated through band matching. The satisfactory effects were gotten when above-mentioned imageprocessing techniques were applied to survey of landuse and desertification of experiment region in GulangCounty, Gansu Province.
Jun Ma Chang of Shandan county is the biggest area of breeding horse in China. Beacausevegetations are degradating with excess of grazing and unreasonable exploitating in recent years, it isobviously important to study condition of vegetations.This paper estimated ground biomass in Jun MaChang of Shandan county. First, field measurements of ground biomass were obtained from 18 plots(1 m×1 m), which were accurately positioned using Global Positioning System. In order to select appropriatefactors as variables for the biomass models, the correlations between biomass and TM4 band, NDVI,RVI, the first principal component and their combinations were calculated.According to the selectedfactors, the multiple linear models of ground biomass as a function of one or more indices, such as NDVI,RVI and etc, were tested by using the step wise regression analysis technique, respectively.The mostoptimal model was chosen among these models and used to estimate ground biomass of typical area in JunMa Chang.
This paper takes Shenmu county as an example. Shenmu county is located in the northern-mostpart of Yulin prefecture. It covers an area of 7 635 km2. Depending on 1986 and 2000 TM images and otherdata, we achieved the land-use change data after interpretation. This paper analyzed the situation of land-use change in temporal and spatial aspects with the GIS and statistic methods. Then this paper analyzedthe situation of landscape change with FRAGSTATS 3.3. The results show that: in recent 15 years thecultivated land and the grassland increased by 5 161.11 hm2and 56 462.25 hm2respectively, the non-usedland decreased by 43 763.01 hm2,the change rate of non-used land is most high. In the direction of land-use change the conversion from non-used land to grassland land and forestland is prominent. The resultsalso show that the landscape structure changed dramatically during the past 15 years. The decrease ofShannon' s diversity index and evenness index manifested that the landscape heterogeneity and landscapediversity decreased. The land conservation works well in recent years.
By interpreting the RS images of 1998 and 2000, this paper concluded the tendency of landuse in Gulang County which was that Gobi and sand were reclaimed into irrigated field in the south ridge of Tengeli Desert, hill dry and plain dry land were returned to grassland from farmland in the south mountain and plain dry area, and these changes caused the decrease of farmland area of 45 312.476 hm2. The desertification type was classified into deflation, water erosion and sandy desertification. The area of desertified land decreased by 8 910.84 hm2, and desertification index S decreased from 2.209 in 1987 to 2.162 in 2000 and 0.118 in the ecologically building zones. In the 25 districts of Gulang County, the desertification index of 15 small towns decreased; that of 10 small towns increased, and the state of desertification reversed locally. Meanwhile, the degree of desertification was aggravated in the districts that were not administered.
Land use and land cover change is the main reason of global change, and it relates to sustainabledevelopment closely. We apply the advanced model“CLUE-S”to simulate land use and land cover changein Zhangye city from 2000 to 2020. Land use type is divided into 6 types, including field, woodland,grassland, water area, town, unused land. Using regression method, we choose 7 kinds of driving factorsthat make important contribution to land use and land cover change in this area. It includes distance tocity, distance to river, distance to road, population density, altitude, slope and aspect. The simulationresult shows that the area of woodland, grassland, water and down increases. However, the area of fieldand unused land decreases.
This paper studies on space structure and productivity characteristic of desert landscape in Linzeusing GIS. The results show: the desert landscape ecosystem of Linze is made up of 4 foundationalelements including rocky desert, sandy desert, conglental desert and road. Among them, conglental deserthas the largest area and highest connectivity, so it is the matrix of the desert landscape ecosystem; road isthe only one kind of corridor, its corridor density is 37.66 m/km2; rocky desert and sandy desert are twokinds of patch types. The genetic type of matrix is belong to environment resource type, and the genetictype of patches have 2 types: rocky desert is rudimental patches type and sandy desert is disturbance type.For the productivity, rocky desert has the highest above ground biomass, which is 6.89 times of conglentaldesert, 28.81 times of sandy desert; the above ground biomass of conglental desert is about 14.51% ofrocky desert, and is 4.18% times of sandy desert; sandy desert has the lowest above ground biomasswhich is 3.47% and 23.91% of rocky desert and conglental desert respectively. The differences vegetationtypes in different desert are not obvious, but due to the great differences in the variation of local water andheat, the plant density changes greatly, resulting in the significant difference in their productivity.Key words:
Spatial data Management plays a very important role in GIS system; thereby how to interact withArcSDE is a key technique of storing and access spatial data for which using ArcSDE to implement themanagement of spatial data. There are several ways can be used to connect ArcSDE, but none can meetthe need of spatial information storage and management in the GIS and Digital Roadbed of the Qinghai-Tibet Railroad System. Therefore, this paper explained the approach of encapsulating the ArcSDE ClientAPI for C programmers into the form of managed code, it not only provides a platform to resolve the issuesof spatial data management, but also bring forward an interface which followed the principle of OOP. Theframework and relationship of the classes, as well as the key techniques in our work is also discussed.
Component technology is the direction of software development nowadays, also is used in theapplication development field of GIS. By an instance of constructing Zhangye Digital Map, as well as theapplication of high resolution remote sensing image within the digital map developing. Meanwhile severalkey techniques involved in system function expansion are discussed also. As a result, one can not onlyconstruct perfect GIS application system very quickly, but also can do the developing of function expansioneasily base on the basic construction work.
Metadata plays important role in the Qinghai-Tibet railway geographical database which storingand managing a mass of heterogeneous data. There are two types of matadata in this system. One isgeographical metadata, which describes geographical background data、DTM、engineering data of railwayand frozen soil data etc. The other is non-spatial metadata including attribute data and business data whichbe used to describe drill、article and field observation data. Both of metadata adopt different criteria. So it' snecessary to use metadata crosswalks to solve the compositive access to datasets using different metadatacriteria, so as to provide user a high-quality service of search and index. XML is the best choice. Thispaper discusses the applicability of Metadata crosswalks in the Qinghai-Tibet railway geographicaldatabase and implementation questions.
Under the background of information, it is introduced that new type digital agriculture expert system was accomplished through integrating 3S technique, network and agriculture expert system. The structure of system base on B/S framework. Then the deign and implement of project is dicussed. At last an instance run in GanSu province, illuminates the system applic ation.
This paper built a system integrating data input and output, management, analysis and decision,and supported by GIS and Decision Support System technologies, and specilized water-saving model, andcombined the state of agricultural water consumption in the Ganzhou district, Zhangye. This system offsetthe limits of traditional agricultural water-saving models on data analysis and expression, and greatlyenhanced the functions of agricultural water-saving DSS. By analyzing the system demand, this paperproposed the framework of agricultural water-saving DSS, and designed the main functions of the system.
With the development of computer and surveying technology, Photogrammetry has run to FullDigital Photographic Measuration stage. As an embranchment of Photogrammetry, Close-rangePhotogrammetry plays a vital part in many aspects, for example the distortion observation, dynamicmonitoring of buildings, and protection of cultural relics. This article emphasizes on introducing themethods for gaining high precision vertical surface geospace data of grottoes cliff with complicatedphysiognomy in large range and the application of Full Digital Photographic Measuration in cultural relicsmaintenance and rehabilitation through the project of digital Close-range Photogrammetry in DunhuanMogao grottoes cliff.
Taking the construction of the main line of Lianhuo Country Road (GZ45) and the Highway fromNiubei (Baoji ) to Tianshui for example, this paper, which is mainly considered from the datapretreatment, the build of virtual reality digital models, cut-fill and 3-D flying simulation, discusses thefollowing methods, including VR-GIS techniques and basic geographical information data such as digitalelevation model (DEM), digital orthography map(DOM), digital line map(DLG), and their application inthe scheme selection, building design, environmental protection and project feasibility analysis.
Airport clearance limit and obstacle location serves as a special one to understand and promotethe relation between clearance limits and obstacles. In this the papercase of Qingyang airport, the dataterrain analysischaracteristics technology and 3D visualization technology are used to get the obstacles dataof airport clearance limit. First, the digital elevation,digital orthoimagery, and the horizontal and verticalpositions of obstacle point are obtained by using the aerial photogrammetry method.Then the solid modelof airport clearance are built. By using terrain analysis method, the location of obstacle are obtained. Atlast,and obstacle location are discussed. Data processing by computer,processes and technologies to getthe data of obstacle location are also descrihed.the Visual GIS module of ERDAS IMAGINE is used tomake the Qingyang airport virtual reality environment, by flying simulation, the user can understand theobstacle of airport clearance visually and vividly.
This paper simply presents basic rules of acquiring Digital Raster Graphic (DRG) and DigitalElevation Model (DEM) data, details the methods and approaches about how to produce three-dimensionallandform landscape map using the existing DRG and DEM data, and expounds three-dimensional landformlandscape map is not a thematic map making from basic mapping digital production, but also a late-modelmultiple mapping production. On the basis of these, the author still explains the application foreground ofthree-dimensional landform landscape map.
To the Earth, solar radiation is the most basic and important energy resource .Because of thecomplexity of land surface (such as aspect, slope etc.), solar radiation will be redistributed on the landsurface. Thus, there exists spatial distribution of solar radiation and leads to the characteristics differencein local climate. According to the development of mountainous solar radiation study in domestic andoverseas ,this paper simulate the solar radiation received on surface through the incoming potential solarradiation model developed by ARC/INFO AML. DEM, AML, Incoming Potential solar radiation
Orthorectification using DEM is an important method for banishing or limiting projection error athill and mountain area. This paper produces 1∶10 000 high precision and meeting criterion DEM throughdigitizing terrain features of 1∶10 000 topographic map such as contour line, spot elevation, typical line,and conversing different coordinate systems. This paper also includes registration, fusion and geometriccorrection for SPOT-5 image data. Based on these, produces orthograph meeting precision using 1∶10 000DEM. The finish of 1∶10 000 DEM and orthograph have important reference value for updating map andbuilding geographic information system of similar local of GANSU.
The improvement and development of atmospheric and oceanic data assimilation system promotesthe study of land data assimilation system (LDAS). In the beginning of 21st century, with the formationof the North American Land Data Assimilation System(NLDAS) and the Global Land Data AssimilationSystem(GLDAS), the study that utilizes satellite and radar data to assimilate soil moisture, surfacetemperature and energy flux has being carried on. At the same time, the land data assimilation has beenthe hotspot of the study in land surface process and hydrology process. In this paper, the main frameworkof land data assimilation system is summarized in detail. The North American Land Data AssimilationSystem (NLDAS) and Global Land Data Assimilation System (GLDAS), European Land DataAssimilation System (ELDAS) and West China Land Data Assimilation System (WCLDAS) areintroduced. At last, some problems that need to be resolved in the study of land data assimilation systemare pointed out.
