简介:利用Landsat系列影像提取水体的方法有很多种,细小的水体漏提或误提现象严重,依靠单一的方法难以取得突破。本研究结合现有的方法提出一种新的思路:1)基于DEM数据提取河网数据;2)辅以河网缓冲区数据将Landsat8影像的1-7波段和全色波段用于多尺度分割,根据形状特征提取线状的细小水体;3)假设2.5m分辨率影像提取的结果为实际水体,与基于像元的MNDWI法进行对比。结果表明水体的总体提取精度提高11.7%,细小水体提取比例从13.3%上升到59.6%,因此本方法简单易行,有利于线状的细小水体提取,可在一定程度上减少山区细小水体的漏提,提高水体提取整体精度。
简介:ThereareobviousdifferencesinthemineralassemblageandmetamorphicP-TconditionsbetweentheeclogitesfromthenorthernandsouthernpartsoftheeasternDabieMountains.ThosefromthenorthernpartofthemountainsaredevelopedinAlpineperidotiteandgneiss.Theyhaveamineralassemblageofgarnet+diopsidewithnoquartz,andwereformedattemperaturesof600℃-740℃.Thosefromthesouthernpartaredevelopedingneissandmarble.Theyconsistofgarnet+omphacite+lessquartzandweremetamorphosedattemperaturesintherangeof650°-800℃.Thesedifferencessuggestthattheformermaybeformedduringthemetamorphismofthedeepsubductedoceaniccrust,whereasthelattermaybegeneticallyrelatedtothesubductionofthecontinentalcrustinthisarea.
简介:OnthebasisofthecharacteristicoftheperfectspatialdistributionoftheT/Paltimeterdata,aspatialharmonictidalanalysisisperformed,whichtransferstidalharmonicconstantsHandgofeachconstituentintoapairofparameters:thecosinepartUandsinepartV.Andeachpartisexpandedintoapolynomial.Thepolynomialcoefficientsareestimatedwithaltimeterdataupontheleastsquarescriteria.ThusthemodelsofprincipaltidalwavesintheSouthChinaSeaareestablished.72cyclesofT/Pdatafromcycle11through82areincludedinthecalculation.Themodelsareevaluatedwithdifferentapproachesanddataset.Theconclusionsarethatthetidemodescanprovidepartialtideamplitudeswith3cmaccuracy,andthatphaselagsdeviationofthosetideswithamplitudelargethan10cmarewithin±10°.