简介:ThispaperdescribestheuseoftheArc/InfoandArcViewGIStoolstoestimatesoilerosionwithUniversalSoilLossEquation(USLE).Calculationsarebedonebyusingcapabilitiesavailable.Thisstudystartwithadigitalelevationmodel(DEM)ofShaanxi,whichwascreatedbydigitizingcontourandspotheightsfromthetopographicmapon1∶250000scaleandgridthemesfortheUSLEKandCfactors.ItisnoteworthythatUSLEKcanbeobtainedbyaddingtheKfactorasanattributetoasoiltheme'stable.TheCcanbeobtainedfromtablesorusingtheinformationaboutlanduseandmanagementgivenbyUSLEprogram.AlandusethemecanbeusedtoaddtheCfactorsasanattributefield.ThepurposeofthisstudyistoestablishspatialinformationofsoilerosionusingUSLEandGISanddiscusstheanalysisofthesoilerosionandslopefailuresinGISandformulatethepossibleframework.
简介:Positionalerroroflinesegmentsisusuallydescribedbyusing'g-band',however,itsbandwidthisinrelationtotheconfidencelevelchoice.Infact,givendifferentconfidencelevels,aseriesofconcentricbandscanbeobtained.Toovercometheeffectofconfidencelevelontheerrorindicator,byintroducingtheunionentropytheory,weproposeanentropyerrorellipseindexofpoint,thenextendittolinesegmentandpolygon,andestablishanentropyerrorbandoflinesegmentandanentropyerrordonutofpolygon.Theresearchshowsthattheentropyerrorindexcanbedetermineduniquelyandisnotinfluencedbyconfidencelevel,andthattheyaresuitableforpositionaluncertaintyofplanargeometryfeatures.
简介:Withrapidscientificdevelopmentandfurtherexplorationtowardsthenature,thehumankindhopestoservethemselvesbymasteringthenaturallaw.CountriesallovertheworldsetmuchvalueonthestudyofAntarcticaandhaveobtainedplentyandsubstantialachievements.SoastostrengthenmutualunderstandingamongthecountriesinAntarcticsurveyingandmappingandsharetheachievements,the'InternationalGISWorkshoponAntarcticKingGeorgeIsland',Wuhan,July6th~7th,2000wassuccessfullyheldintheLectureHalloftheNationalLaboratoryforInformationEngineeringinSurveying,MappingandRemoteSensing(LIESMARS).ItwasjointlyheldbytheNationalResearchCenteronAntarcticSurveyingandMappingandLIESMARS,andsponsoredbytheNationalPolarRegionInspectionOffice,NationalNaturalScientificFoundationCommittee,theStateBureauofSurveyingandMapping,theformerWuhanTechnicalUniversityofSurveyingandMapping.
简介:这研究的主要目的是在伊拉克的南部的部分的一个代表性的区域在最后20年期间加亮环境变化指示物(Basrah省作为一个盒子被拿)可伸缩理解用印射的1:250000导致了普遍环境降级现象的主要原因。遥感和GIS软件被用来分类Landsat在1990的TM和在进五的2003形象的LandsatETM+打使用和陆地盖子(LULC)班:植被土地,沙陆地,城市的区域,闲置的陆地,和水身体。监督分类和规范的差别植被索引(NDVI),规范的差别逐渐增加索引(NDBI),规范的差别水索引(NDWI),规范的差别咸度索引(NDSI),并且表层土谷物尺寸索引(GSI)在这研究被采用并且分别地过去常检索它的班边界。结果在植物的盖子(514.9km2)和沙沙丘累积(438.6km2)的增加显示出清楚的恶化,为10.1,和10.6%的财务,分别地全部的学习区域。另外,在水身体区域的减少被检测(228.9km2)。沙区域累积在全部的学习区域增加了,与年度增加扩大率(33.7km2???????????吗??
简介:Therearemainlyfourkindsofmodelstorecordanddealwithhistoricalinformation.Bytakingthemasreference,thespatio-temporalmodelbasedoneventsemanticsisproposed.Inthismodel,accordingtothewayfordescribinganevent,alltheinformationaredividedintofivedomains.Thispaperdescribesthemodelbyusingthelandparcelchangeinthecadastralinformationsystem,andexpoundsthemodelbyusingfivetablescorrespondingtothefivedomains.Withtheaidofthismodel,sevenexamplesaregivenonhistoricalquery,tracebackandrecurrence.Thismodelcanbeimplementedeitherintheextendedrelationaldatabaseorintheobject-orienteddatabase.
简介:Onthebasisoftheprinciplesofsimplerandomsampling,thestatisticalmodelofrateofdisfigurement(RD)isputforwardanddescribedindetail.AccordingtothedefinitionofsimplerandomsamplingfortheattributedatainGIS,themeanandvarianceoftheRDarededucedasthecharacteristicvalueofthestatisticalmodelinordertoexplainthefeasibilityoftheaccuracymeasurementoftheattributedatainGISbyusingtheRD.Moreover,onthebasisofthemeanandvarianceoftheRD,thequalityassessmentmethodforattributedataofvectormapsduringthedatacollectingisdiscussed.TheRDspreadgraphisalsodrawntoseewhetherthequalityoftheattributedataisundercontrol.TheRDmodelcansyntheticallyjudgethequalityofattributedata,whichisdifferentfromothermeasurementcoefficientsthatonlydiscussaccuracyofclassification.
简介:Uptonow,detailedstrategiesandalgorithmsofautomaticchangedetectionforroadnetworksbasedonGIShavenotbeendiscussed.Thispaperdiscussestwodifferentstrategiesofautomaticchangedetec-tionforimageswithlowresolutionandhighresolutionusingoldGISdata,andpresentsabufferdetectionandtracingalgorithmfordetectingroadfromlow-resolutionimagesandanewprofiletracingalgorithmfordetectingroadfromhigh-resolutionimages.Forfeature-levelchangedetection(FL-CD),aso-calledbufferdetectionalgo-rithmisproposedtodetectchangesoffeatures.SomeideasandalgorithmsofusingGISpriorinformationandsomecontextinformationsuchassubstructuresofroadinhigh-resolutionimagestoassistroaddetectionandextractionaredescribedindetail.