简介：AdetailedsurveyofthereefsintheNanshaIslands’seathatareofstrategicimportanceisconducivetotheirfuturedevelopment.Inthisstudy,atotalof50Landsat8operationallandimager(OLI)imageswereusedtoanalyzethegeologicalfeaturesandspectralcharacteristicsoftheNanshareefs.Theexposedislands/sandbanks,reefflatsandsub-tidalreefswereidentifiedwiththenear-infraredband,theredandgreenbands,andtheblueband,respectively.BasedontherelationshipsamongvariouscharacteristicsandbandsillustratedintheOLIimages,themaximumbetween-clustervariancethresholdalgorithm(OTSUmethod)andthemathematicalmorphologywereemployedtoextractcharacteristicparametersofthespatialgeometryofthereefsfromtoptobottom,whichweresubsequentlyoperatedbyaseriesofpost-processingmethodssuchasvectorization,simplificationandtopologicalanalysis.Amongthe132standalonereefsand16atollsthatareidentifiedinthestudy,fourreefshaveyettobenamedintheStandardNamesofVariousIslandsintheSouthChinaSeaandthewebsiteNanshaIslandsOnline(http://www.nansha.org/).Another24onesareexposedtotheatmosphereevenduringhightides.TaipingIslandwithanareaof0.57km~2representsthelargestexposedgeologicalfeature.Thisstudydemonstratedtheapplicabilityofmedium-resolutionsatelliteimagestoderivethecoralreefinformationeffectivelyandthusprovidedinformationfortherelateddepartmentsthatareresponsibletomanagethecoast.Animprovedresolutionofmultispectralbandswiththepanchromaticbandinhigherspatialresolution(15mforOLIimage)isexpectedtoprovideanoptimumsatellitebasedapproachtomapmarinehabitats.

简介：Weusedgeographicinformationsystemapplicationsandstatisticalanalysestoclassifyyoung,prematureforestareasinsoutheasternGeorgiausingcombineddatafromLandsatTM5satelliteimageryandgroundinventorydata.Wedefinedprematurestandsasforestswithtreesupto15yearsold.Weestimatedtheprematureforestareasusingthreemethods:maximumlikelihoodclassification(MLC),regressionanalysis,andk-nearestneighbor(kNN)modeling.Overallaccuracy(OA)ofclassifyingtheprematureforestusingMLCwas82%andtheKappacoefficientofagreementwas0.63,whichwasthehighestamongthemethodsthatwehavetested.ThekNNapproachrankedsecondinaccuracywithOAof61%andaKappacoefficientofagreementof0.22.RegressionanalysisyieldedanOAof57%andaKappacoefficientof0.14.WeconcludethatLandsatimagerycanbeeffectivelyusedforestimatingprematureforestareasincombinationwithimageprocessingclassifierssuchasMLC.

简介：以2003年5月29日福州市LandsmETM＋影像为数据源，对2种地表温度空间降尺度算法——EM算法和HUTS算法进行实验、比较与分析,EM算法是利用高空间分辨率的地表比辐射率对低空间分辨率的亮度温度影像进行调节，从而达到提高热红外影像空间分辨率的目的；HUTS算法则是引入了归一化差异植被指数NDVI和地表反照率d，通过在低空间分辨率拟合二者与地表温度LST之间的关系，然后根据其尺度不变性，将该关系应用到高空间分辨率的影像上，从而达到提高热红外影像空间分辨率的目的．研究结果表明：1）2种算法所得结果影像都能在有效提高空间分辨率的同时较好地保持了原始地表温度影像的空间分布特征，达到了较好的降尺度效果；2）以RMSE为定量评价指标，HUTS算法要略优于EM算法，其中，EM算法的RMSE为1．2494，而HUTS算法仅为0．9869．

简介：Forthepurposeofofforestation,planninganddevelopmentintheThree-NorthRegion,aseriesof6LandsatTMscenesfrom1996to1997wereusedtoclassifyland-useconditionsinthewholeKorqinSandyLandsateasternpartofInnerMongolia,China,withanareaofabout430×306squarekilometers.Lateron,Siteclassiflcationwasmadeandmappedforthe4southernsandycounties.Theannotationsymbolforeachagglomerationofsiteconditioniscomprisedofsixparts:landunit,landusepattern,soi...

简介：Land-usechangeisanimportantaspectofglobalenvironmentchange.Itis,inasense,thedirectresultofhumanactivitiesinfluencingourphysicalenvironment.Thispaperanalyzedtheland-usechangeinNortheastChinaduring1985-2000basedonLandsatTMimages.ItdividesNortheastChinaintofiveland-usezonesbasedonthedynamicdegreemodelofland-use:woodland/grassland-arablelandconversionzone,dryland-paddyfieldconversionzone;urbanexpansionzone,interlockedzoneoffarmingandpasturingandreclamationandabandonzone.Thefindingsincludetheobviousincreaseofcroplandarea,paddyfieldanddrylandincreasedby75and276thousandhm2respectively;urbanareasexpandedrapidly,areasoftownandruralresidenceincreasedby76.8thousandhm2;areasofforestsandgrasslanddecreasedsharplywiththeamountsof1399and1521thousandhm2respectively;areasofwaterbodyandunusedlandincreasedby148and514thousandhm2respectively.Thispaperalsodiscussesthedriving

简介：当前，Landsat家庭传感器的历史的档案图象可能是为自从1970年代，追踪全球纵的变化的最有效的数据产品。然而，云范围的度和程度的问题总是是挑战并且全球区别地变化。到目前为止，Landsat观察的云盖子(CC)的获得概率(AP)分析在地区性的规模与不同传感器被进行了。到我们的知识，为越过中国的最新发射的Landsat-8运作的陆地成像器(OLI)的CC概率分析没被报导。每月，为LandsatOLI在这糊季节、年度的AP(44,228总共)在与各种各样的CC阀值从2013年4月获得到2016年10月的中国上的图象被分析。结果显示出那：首先，在在CC阀值的中国上的所有OLI数据的累积平均AP30%是大约49.6%它越过中国说明了OLI形象的可获得性。第二，OLI观察的10%，20%，和30%CC阀值的空间模式，有降水分布的与一致的井分开了由各自200公里，400公里，和800公里isohyetal线。第三，有30%CC阀值的图象的AP在58.7%的10月特别在秋天和冬季是最高的，当相应最低概率发生在41.0%的6月时。最后，在有30%CC阀值的指向的图象的AP的空间差别是相当重要的。在地区性的规模，胡焕勇人口线的干旱、半干旱的区域，内陆河和Songliao河盆，和西北的方面有获得高质量的图象的更大的可能性。我们的学习建议OLI形象满足为陆地表面监视需要的数据要求，尽管在那里存在在在在30%CC阀值的中国上的AP的明显的时间空间的差别。

简介：FalsecolorLandsatETM+(bands7,4,2inRGB)andSRTMimagesoftheEl-Faiyumdepression,Egypt,highlightsmajorNE-SWfaultsandotherlineamentstrendingNW-SEandN-S.AirbornemagneticdatarevealsomeE-WsubsurfacefaultswhicharenotrecognizedonLandsatETM+andSRTMimages.Ratioimages(5/7,3/1,4/3)and(5/7,5/1,4)wereusedforlithologicaldiscriminationofdifferentrocktypes.TheEl-FaiyumareaisoccupiedbysedimentaryrocksofMiddleEocene,UpperEocene,Oligocene,LowerMiocene,Pliocene,PleistoceneandHolocene.UnderstandingthestructuralregimeofEl-FaiyumdepressionintheWesternDesertofEgyptissignificantinrelationtotheneotectonicsoftheNileDeltaandtothedevelopmentofnewcommunitieswestofthedelta.TheareaiscoveredbyLateCretaceous,MiddletoLateEocenedeposits,Oligocenedeposits(comprisingfluviatilesedimentsandbasaltsheets)andPlioceneandQuaternaryalluviumandsanddeposits.Newgeologicalandstructuralmapswerepreparedatascaleof1:100000usingLandsatETM+andSRTMimagescoupledwithextensivefieldwork.ThemajorstructuraltrendsareE-W,ENE,NSandNW-thesametrendsobservedelsewhereinNorthAfricafromNWSudantoNEEgyptincludingnorthandcentralSinai.El-Faiyumdepressionisastructurally-controlledtectonicbasin,markedbynortheast-strikingfaultsalongitsnorthernmargin.ThesefaultsareparalleltosimilarfaultsoftheSyrianarcfoldbelt,whichincludesagroupofrelatedfaults,folds,push-upstructures,andbasins.QarunLakeislocatedinthenorthernpartofEl-Faiyumdepression,ataright-stepbetweentwostrandsoftheNEstrikingfaultsystem.WehavesuggestedelsewherethatEl-Faiyumdepressionisapull-apartbasinrelatedtoextensionbetweenthesemismatchedstrandsofstrike-slipfaults.TheE-WstructuresareprobablyrelatedtotherelativemotionbetweensouthEuropeandnorthEgyptandclosureoftheNeotethys.Thecontinuationofthesefaultsinthepresentareaisonlydetected

简介：基于Landsat8影像数据,根据覃志豪等人提出的单窗算法,分别用2个热红外波段反演2014年4月17日福州市区地表温度,并将反演结果与研究区部分气象站点当天的实测温度进行对比验证,发现利用波段10反演得到的地温与实际观测值更加接近,说明利用单窗算法可以较好地反演福州市地表温度,对于Landsat8影像来说,波段10更适合用于反演地表温度。本研究采用面向对象分类方法对研究区范围内的土地利用类型进行解译,并计算归一化植被指数（NDVI）,进而探讨二者与对应地表温度之间的相关性,结果显示土地利用类型与地表温度具有较强的相关性,同时NDVI与地表温度之间存在着较为显著的负相关性。

简介：摘要:植被不仅是生态系统的重要组成部分，对生态平衡、水源涵养、防风固沙等也具有重要意义。植被作为生态环境的重要指征指标，了解攀枝花市仁和区植被影响因素及时空变化规律，能为当地管理部门进行生态环境管理及保护供理论依据具有重要意义。植被指数可以直接反应植被覆盖度情况，所以可以通过研究植被指数来反应植被情况。