简介:ThefeasibilityofERSSARTandemdataformappingforestandnon-forestcoverinChinawasevaluatedoverZengchengCountyintheSouthChina.Anaccuracyof75%hasbeenachieved.Then,theMACFERST(MappingChinaForestwithERSSARTandemdata)projectstartedbytheMinistryofScienceandTechnology(MOST)ofChinaandtheEuropeanSpaceAgency(ESA)in1999.Thegenerationofalarge-scaleforestmaprequiressolvingproblemssuchasthegeoreferencingandmosaickingofverylongimagestripscov...
简介:ThepurposeofthispaperistostudytheRSdatawebservicesandrelatedsubjectsofdatastorageanddatamanagement.Basedonananalysisofthepresentsituationanddevelopmenttrendofstorageandmanagementofrasterdataandwebservicetechnology,amanagementandservicesystemarchitectureforRemoteSensingrasterdatabasedonwebservicetechnologieswasdeveloped,theimplementationmethodologiesofthekeytechnologyofthesystemwereexploredandaprototypeofthesystemwasillustrated.
简介:Basedonsixthandseventhnationalforestryinventorydataofthesixprovinces,includingGuangdong,Jiangxi,Guizhou,Shaanxi,JilinandBeijing,thethreemethods(IPCC,continuousfunctionforbiomassexpansionfactorandweightedbiomassregressionmodel)wereselectedtoestimatewoodbiomassinthispaper.Theestimationofthethreemethodswerecomparedandanalyzedfromcalculatingprocess,methodcharacters,repeatabilityandverifiabilitytostabilityofgrowthrateofbiomassbetweentwoperiods.TheresultsshowedthetotalbiomassestimatedbyIPCCmethodwithvariableBEF2waslarge,thetotalbiomassestimatedbyIPCCmethodwithconstantBEF2wassmallandthetotalbiomassesestimatedbycontinuousfunctionforbiomassexpansionfactorandweightedbiomassregressionmodelweremiddle.Thebiomassexpansionfactorderivedfromweightedregressionmodelwasmoststableinthedifferentprovinces.Basedontheseventhnationalforestryinventorydata,thebiomassexpansionfactorsofvariouskindsoftreespeciesderivedfromIPCCandtheweightedregressionmodelweremorestablethanthebiomassexpansionfactorsderivedfromcontinuousfunctionmethod.Thegrowthrateofbiomassbetweentwoperiodswasthesameregularpatternasthebiomassexpansionfactors.
简介:Climateisadominantenvironmentalfactorinbuildingecosystemstructureanddrivingbioticdynamicswithtopographicdependenceonspatialdistribution.Thispaperdemonstratestheapplicationofinterpolationtechniquetodescribespatialclimatedistribution.Adigitalelevationmodel(DEM)inresolutionof0.01degreeoflatitudeandlongitudehasbeendevelopedbecausetheincorporationofspatialdependenceontopographyiscrucialtoaccuracyofinterpolation.Climatedatafromsparseanddiscr...
简介:Forestgrowthismainlycurrentlymonitoredusingin-situmeasurementsinnortheastofChina.Toeffectivelymonitorforestgrowthdisturbanceatlargescale,weattemptedtouseremotesensingtechnique,particularly,timeseriesMODISdatafrom2004to2006.Theannualtimeseriesof8-dayenhancedvegetationindex(EVI)datasetwasgeneratedandsmoothedusingaSavitzky-Golayfilter.TheEVItrajectoryduringgrowthseasonwassimulatedusingalogisticmodel.Fromthesimulatedtrajectory,theEVIareaofgrowthseasonandannualEVIentropywerecalculated.Thesetwofactorswerecombinedtomapthedisturbanceregionsofforestgrowth.Finally,thedisturbanceregionswereverifiedusingasetofrandomsamples.Theresultindicatesthatthedisturbancepointshavedistinctivelyhigherentropyandlowerpeak.SomeofthesepointsalsoshowabruptEVIdeclineduringthemidseasonofthepeakphasesordoublepeaks.Thisapproachisdemonstratedtobefeasiblefordisturbancemonitoringofforestgrowth.
简介:作为由地面生产的数据的数量,为根渗透雷达(GPR)大,传播和数据的存储消费大资源。减轻这个问题,我们这里用混乱粒子群建议一个根成像算法最佳(CPSO)压缩了根据根空间的稀少基于GPR数据察觉到。雷达数据以稀少的方式被分解,观察,测量并且代表,因此根图象能与有限数据被重建。第一,雷达信号测量和稀少的表示被实现,并且解决方案空格被小浪基础和高斯随机矩阵建立;第二,匹配的功能被看作健康功能,并且最好的健康价值被一个PSO算法发现;然后,混乱搜索被用来获得全球最佳的操作员;最后,根图象被最佳的操作符重建。分别地,从美国GSSIGPR的A扫描数据,B扫描数据,和复杂数据在试验性的测试被使用。为B扫描数据,计算时间被减少60?%和PSNR被改进5.539?dB;为实际的根数据成像,重建PSNR是26.300?dB,和全部的计算时间仅仅是67.210?s。CPSO-OMP算法克服本地最佳套住的问题并且包括地在重建期间提高精确。
简介:WemappedtheforestcoverofKhadimnagarNationalPark(KNP)ofSylhetForestDivisionandestimatedforestchangeoveraperiodof22years(1988-2010)usingLandsatTMimagesandotherGISdata.SupervisedclassificationandNormalizedDifferenceVegetationIndex(NDVI)imageclassificationapproacheswereappliedtotheimagestoproducethreecoverclasses,viz.denseforest,mediumdenseforest,andbareland.Thechangemapwasproducedbydifferencingclassifiedimageriesof1988and2010asbeforeimageandafterimage,respectively,inERDASIMAGINE.Errormatrixandkappastatisticswereusedtoassesstheaccuracyoftheproducedmaps.Overallmapaccuraciesresultingfromsupervisedclassificationof1988and2010imagerieswere84.6%(Kappa0.75)and87.5%(Kappa0.80),respectively.Forestcoverstatisticsresultingfromsupervisedclassificationshowedthatdenseforestandbarelanddeclinedfrom526ha(67%)to417ha(59%)and105ha(13%)to8ha(1%),respectively,whereasmediumdenseforestincreasedfrom155ha(20%)to317ha(40%).ForestcoverchangestatisticsderivedfromNDVIclassificationshowedthatdenseforestdeclinedfrom525ha(67%)to421ha(54%)whilemediumdenseforestincreasedfrom253ha(32%)to356ha(45%).BothsupervisedandNDVIclassificationapproachesshowedsimilartrendsofforestchange,i.e.decreaseofdenseforestandincreaseofmediumdenseforest,whichindicatesdenseforesthasbeenconvertedtomediumdenseforest.Areaofbarelandwasunchanged.Illicitfelling,encroachment,andsettlementnearforestscausedthedenseforestdeclinewhileshortandlongrotationplantationsraisedinvariousyearscausedtheincreaseinareaofmediumdenseforest.ProtectivemeasuresshouldbeundertakentocheckfurtherdegradationofforestatKNP.
简介:Usingthemulti-temporalLandsatdataandsurveydataofnationalresources,theauthorsstudiedthedynamicsofcultivatedlandandlandcoverchangesoftypicalecologicalregionsinChina.TheresultsofinvestigationshowedthatthewholedistributionofthecultivatedlandshiftedtoNortheastandNorthwestChina,andasaresult,theecologicalqualityofcultivatedlanddroppeddown.TheseacoastandcultivatedlandintheareaofYellowRiverMouthexpandedbyanincreasingrateof0.73km?a-1,withadepositingrateof2.1km?a-1.ThedesertificationareaofthedynamicofHorqinSandyLandincreasedfrom60.02%ofthetotallandareain1970sto64.82%in1980sbutdecreasedto54.90%inearly1990s.AstothechangeofNorthTibetlakes,thewaterareaoftheNamuLakedecreasedby38.58km2fromyear1970to1988,withadecreasingrateof2.14km2?a-1.
简介:Background:Overthelastdecades,manyforestsimulatorshavebeendevelopedfortheforestsofindividualEuropeancountries.Theunderlyinggrowthmodelsareusuallybasedonnationaldatasetsofvaryingsize,obtainedfromNationalForestInventoriesorfromlong-termresearchplots.Manyofthesemodelsincludecountry-andlocation-specificpredictors,suchassitequalityindicesthatmayaggregateclimate,soilpropertiesandtopographyeffects.Consequently,itisnotsensibletocomparesuchmodelsamongcountries,anditisoftenimpossibletoapplymodelsoutsidetheregionorcountrytheyweredevelopedfor.However,thereisaclearneedformoregenericallyapplicablebutstilllocallyaccurateandclimatesensitivesimulatorsattheEuropeanscale,whichrequiresthedevelopmentofmodelsthatareapplicableacrosstheEuropeancontinent.ThepurposeofthisstudyistodeveloptreediameterincrementmodelsthatareapplicableattheEuropeanscale,butstilllocallyaccurate.Wecompiledandusedadatasetofdiameterincrementobservationsofover2.3milliontreesfrom10NationalForestInventoriesinEuropeandasetof99potentialexplanatoryvariablescoveringforeststructure,weather,climate,soilandnutrientdeposition.Results:Diameterincrementmodelsarepresentedfor20species/speciesgroups.Selectionofexplanatoryvariableswasdoneusingacombinationofforwardandbackwardselectionmethods.Theexplainedvariancerangedfrom10%to53%dependingonthespecies.Variablesrelatedtoforeststructure(basalareaofthestandandrelativesizeofthetree)contributedmosttotheexplainedvariance,butenvironmentalvariableswereimportanttoaccountforspatialpatterns.Thetypeofenvironmentalvariablesincludeddifferedgreatlyamongspecies.Conclusions:ThepresenteddiameterincrementmodelsarethefirstoftheirkindthatareapplicableattheEuropeanscale.Thisisanimportantsteptowardsthedevelopmentofanewgenerationofforestdevelopmentsimulatorsthatcan
简介:Forestsareamongthemostimportantcarbonsinksonearth.However,theircomplexstructureandvastareasprecludeaccurateestimationofforestcarbonstocks.Datasetsfromforestmonitoringusingadvancedsatelliteimageryarenowusedininternationalpolicyagreements.DatasetsenabletrackingofemissionsofCO2intotheatmospherecausedbydeforestationandothertypesofland-usechanges.TheaimofthisstudyistodeterminethecapabilityofSPOT-HRGSatellitedatatoestimateabovegroundcarbonstockinadistrictofDarabkolaresearchandtrainingforest,Iran.Preprocessingtoeliminateorreducegeometricerrorandatmosphericerrorwereperformedontheimages.Usingclustersampling,165sampleplotsweretaken.Of165plots,81wereinnaturalhabitats,and84wereinforestplantations.Followingthecollectionofgrounddata,biomassandcarbonstockswerequantifiedforthesampleplotsonaperhectarebasis.Nonparametricregressionmodelssuchassupportvectorregressionwereusedformodelingpurposeswithdifferentkernelsincludinglinear,sigmoid,polynomial,andradialbasisfunction.Theresultsshowedthatathird-degreepolynomialwasthebestmodelfortheentirestudiedareashavinganrootmeansquareerror,biasandaccuracy,respectively,of38.41,5.31,and62.2;42.77,16.58,and57.3%forthebestpolynomialfornaturalforest;and44.71,2.31,and64.3%forafforestation.Overall,theseresultsindicatethatSPOTHRGsatellitedataandsupportvectormachinesareusefulforestimatingabovegroundcarbonstock.
简介:Background:Remotesensing-basedmappingofforestEcosystemService(ES)indicatorshasbecomeincreasinglypopular.TheresultingmapsmayenabletospatiallyassesstheprovisioningpotentialofESsandprioritizethelanduseinsubsequentdecisionanalyses.However,themappingisoftenbasedonreadilyavailabledata,suchaslandcovermapsandotherpubliclyavailabledatabases,andignoringtherelateduncertainties.Methods:Thisstudytestedthepotentialtoimprovetherobustnessofthedecisionsbymeansoflocalmodelfittinganduncertaintyanalysis.Thequalityofforestlanduseprioritizationwasevaluatedundertwodifferentdecisionsupportmodels:eitherusingthedevelopedmodelsdeterministicallyorincorporationwiththeuncertaintiesofthemodels.Results:PredictionmodelsbasedonAirborneLaserScanning(ALS)dataexplainedthevariationinproxiesofthesuitabilityofforestplotsformaintainingbiodiversity,producingtimber,storingcarbon,orprovidingrecreationaluses(berrypickingandvisualamenity)withRMSEsof15%–30%,dependingontheES.TheRMSEsoftheALS-basedpredictionswere47%–97%ofthosederivedfromforestresourcemapswithasimilarresolution.Duetoapplyingasimilarfieldcalibrationsteponbothofthedatasources,thedifferencecanbeattributedtothebetterabilityofALStoexplainthevariationintheESproxies.Conclusions:Despitethedifferentaccuracies,proxyvaluespredictedbyboththedatasourcescouldbeusedforapixel-basedprioritizationoflanduseataresolutionof250m~2,i.e.,inaconsiderablymoredetailedscalethanrequiredbycurrentoperationalforestmanagement.TheuncertaintyanalysisindicatedthatmapsoftheESprovisioningpotentialshouldbepreparedseparatelybasedonexpectedandextremeoutcomesoftheESproxymodelstofullydescribetheproductionpossibilitiesofthelandscapeundertheuncertaintiesinthemodels.
简介:Background:Treelinedynamicshaveinevitableimpactsontheforesttreelinestructureandcomposition.ThepresentresearchsoughttoestimatetreelinemovementandstructuralshiftsinresponsetorecentwarminginCehennemdere,Turkey.Afterimplementinganatmosphericcorrection,thegeo-shiftingofimageswasperformedtomatchimagestogetherforaperpixeltrendanalysis.WedevelopedanewapproachbasedontheNDVI,LST(landsurfacetemperature)data,airtemperaturedata,andforeststandmapsfora43-yearperiod.Theforesttreelineborderwasmappedontheforeststandmapsfor1970,1992,2002,and2013toidentifyshiftsinthetreelinealtitudes,andthenprofilestatisticswerecalculatedforeachperiod.Twentysampleplots(10×10pixels)wereselectedtoestimatetheNDVIandLSTshiftsacrosstheforesttimberlineusingper-pixeltrendanalysisandnon-parametricSpearman’scorrelationanalysis.Inaddition,thespatialandtemporalshiftsintreelinetreespecieswerecomputedwithintheselectedplotsforfourtimeperiodsontheforeststandmapstodeterminethepioneertreespecies.Results:Astatisticallysignificantincreasingtrendinallclimatevariableswasobserved,withthehighestslopeinthemonthlyaveragemeanJulytemperature(tau=0.62,ρ<0.00).Theresultantforeststandmapsshowedageographicalexpansionofthetreelineinboththehighestaltitudes(22m–45m)andthelowestaltitudes(20m–105m)from1970to2013.TheperpixeltrendanalysisindicatedanincreasingtrendintheNDVIandLSTvalueswithintheselectedplots.Moreover,increasesintheLSTwerehighlycorrelatedwithincreasesintheNDVIbetween1984and2017(r=0.75,ρ<0.05).CedruslibaniandJuniperuscommunisapp.weretwopioneertreespeciesthatexpandedandgrewconsistentlyonopenlands,primarilyonrocksandsoil-coveredareas,from1970to2013.Conclusion:Thepresentstudyilustratedthatforesttreelinedynamicsandtreelinestructuralchangescanbedetectedusingtwodata
简介:Background:Overthelastdecadesinteresthasgrownonhowclimatechangeimpactsforestresources.However,oneofthemainconstraintsisthatmeteorologicalstationsarefiddledwithmissingclimaticdata.Thisstudycomparedfiveapproachesforestimatingmonthlyprecipitationrecords:inversedistanceweighting(IDW),amodificationofIDWthatincludeselevationdifferencesbetweentargetandneighboringstations(IDWm),correlationcoefficientweighting(CCW),multiplelinearregression(MLR)andartificialneuralnetworks(ANN).Methods:Acompleteseriesofmonthlyprecipitationrecords(199.5-2012)fromtwentymeteorologicalstationslocatedincentralChilewereused.Twotargetstationswereselectedandtheirneighboringstations,locatedwithinaradiusof25km(3stations)and50km(9stations),wereidentified.Cross-validationwasusedforevaluatingtheaccuracyoftheestimationapproaches.Theperformanceandpredictivecapabilityoftheapproacheswereevaluatedusingtheratiooftherootmeansquareerrortothestandarddeviationofmeasureddata(RSR),thepercentbias(PBIAS),andtheNash-Sutcliffeefficiency(NSE).Fortestingthemainandinteractiveeffectsoftheradiusofinfluenceandestimationapproaches,atwo-levelfactorialdesignconsideringthetargetstationastheblockingfactorwasused.Results:ANNandMLRshowedthebeststatisticsforallthestationsandradiusofinfluence.However,theseapproacheswerenotsignificantlydifferentwithIDWm.InclusionofelevationdifferencesintoIDWsignificantlyimprovedIDWmestimates.Intermsofprecision,similarestimateswereobtainedwhenapplyingANN,MLRorIDWm,andtheradiusofinfluencehadasignificantinfluenceontheirestimates,weconcludethatestimatesbasedonnineneighboringstationslocatedwithinaradiusof50kmareneededforcompletingmissingmonthlyprecipitationdatainregionswithcomplextopography.Conclusions:ItisconcludedthatapproachesbasedonANN,MLRandIDWmhadthebestperformanceintwosectorslocatedinso
简介:Background:Theimportanceofstructurallydiverseforestsfortheconservationofbiodiversityandprovisionofawiderangeofecosystemserviceshasbeenwidelyrecognised.However,toolstoquantifystructuraldiversityofforestsinanobjectiveandquantitativewayacrossmanyforesttypesandsitesarestillneeded,forexampletosupportbiodiversitymonitoring.Theexistingapproachestoquantifyforeststructuraldiversityarebasedonsmallgeographicalregionsorsingleforesttypes,typicallyusingonlysmalldatasets.Results:HerewedevelopedanindexofstructuraldiversitybasedonNationalForestInventory(NFI)dataofBadenWurttemberg,Germany,astatewith1.3millionhaofdiverseforesttypesindifferentownerships.Basedonaliteraturereview,11aspectsofstructuraldiversitywereidentifiedaprioriascruciallyimportanttodescribestructuraldiversity.Aninitialcomprehensivelistof52variablesderivedfromNationalForestInventory(NFI)datarelatedtostructuraldiversitywasreducedbyapplyingfiveselectioncriteriatoarriveatonevariableforeachaspectofstructuraldiversity.Thesevariablescomprise1)quadraticmeandiameteratbreastheight(DBH),2)standarddeviationofDBH,3)standarddeviationofstandheight,4)numberofdecayclasses,5)bark-diversityindex,6)treeswithDBH>40cm,7)diversityoffloweringandfructification,8)averagemeandiameterofdowneddeadwood,9)meanDBHofstandingdeadwood,10)treespeciesrichnessand11)treespeciesrichnessintheregenerationlayer.Thesevariableswerecombinedintoasimple,additiveindextoquantifythelevelofstructuraldiversity,whichassumesvaluesbetween0and1.Weappliedthisindexinanexemplarywaytobroadforestcategoriesandownershipstoassessitsfeasibilitytoanalysestructuraldiversityinlarge-scaleforestinventories.Conclusions:Theforeststructureindexpresentedherecanbederivedinasimilarwayfromstandardinventoryvariablesformostotherlarge-scaleforestin
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:Background:Inthispaper,aregressionmodelforpredictingthespatialdistributionofforestcockchaferlarvaeintheHessianRiedregion(Germany)ispresented.Theforestcockchafer,anativebioticpest,isamajorcauseofdamageinforestsinthisregionparticularlyduringtheregenerationphase.ThemodeldevelopedinthisstudyisbasedonasystematicsampleinventoryofforestcockchaferlarvaebyexcavationacrosstheHessianRied.Theseforestcockchaferlarvaedatawerecharacterizedbyexcesszerosandoverdispersion.Methods:Usingspecificgeneralizedadditiveregressionmodels,differentdiscretedistributions,includingthePoisson,negativebinomialandzero-inflatedPoissondistributions,werecompared.Themethodologyemployedallowedthesimultaneousestimationofnon-linearmodeleffectsofcausalcovariatesand,toaccountforspatialautocorrelation,ofa2-dimensionalspatialtrendfunction.Inthevalidationofthemodels,boththeAkaikeinformationcriterion(AIC)andmoredetailedgraphicalproceduresbasedonrandomizedquantileresidualswereused.Results:ThenegativebinomialdistributionwassuperiortothePoissonandthezero-inflatedPoissondistributions,providinganearperfectfittothedata,whichwasproveninanextensivevalidationprocess.Thecausalpredictorsfoundtoaffectthedensityoflarvaesignificantlyweredistancetowatertableandpercentageofpureclaylayerinthesoiltoadepthof1m.Modelpredictionsshowedthatlarvadensityincreasedwithanincreaseindistancetothewatertableuptoalmost4m,afterwhichitremainedconstant,andwithareductioninthepercentageofpureclaylayer.Howeverthislattercorrelationwasweakandrequiresfurtherinvestigation.The2-dimensionaltrendfunctionindicatedastrongspatialeffect,andthusexplainedbyfarthehighestproportionofvariationinlarvadensity.Conclusions:Assuchthemodelcanbeusedtosupportforestpractitionersintheirdecisionmakingforregenerationandforestprotecti