Patchanalysis指数简单对译.docx

Patchanalysis指数简单对译.docx

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Patchanalysis指数简单对译

MetricDefinitions（fromMcGarigalandMarks,1994andMcGarigalandMarks,1995）

ClassArea（CA）

Sumofareasofallpatchesbelongingtoagivenclass.

Example:

ConiferClassArea（CA）=359047.844+......+65819.984

CA=69.6626hectares

Ifthemapunitsarenotspecified（i.e.,DataFrameproperties;seeSetmapunits）and"StateareasinHectares"hasnotbeenselectedinthe"AdvancedOptions"ofthe"SpatialStatistics"dialogbox,thentheresultingstatisticswillbereportedinnativemapunits（vectorlayers（themes）only）.

Intheexample;CA=696626.012（mapunits）.Thisisthecaseformoststatistics.

LandscapeArea（TLA）

Sumofareasofallpatchesinthelandscape.

Example:

LandscapeArea（TLA）=46872.719+359047.844+...+62423.574

TLA=184.11hectares

PercentageofLandscape（ZLAND）

Whenanalyzingbyclass,ZLANDisthepercentageofthetotallandscapemadeupofthecorrespondingclass（patchtype）.

NumberofPatches（NumP）

Totalnumberofpatchesinthelandscapeif"AnalyzebyLandscape"isselected,orNumberofPatchesforeachindividualclass,if"AnalyzebyClass"isselected.

Example:

ClassLevel:

NumberofPatches（NumP）

Mixedwood=5,Conifer=4,Deciduous=5

LandscapeLevel:

NumberofPatches（NumP）=14

PatchRichness（PR）

PRisthenumberofdifferentpatchtypeswithinthelandcape'sboundary.

PatchRichnessDensity（PRD）

PRDisequaltoPRdividedbythetotalareaofthelandscape（metressquared）multipliedby10,000andthen100（toconverttohundredsofhectares）.

LargestPatchIndex（LPI）

TheLPIisequaltothepercentofthetotallandscapethatismadeupbythelargestpatch.

Whentheentirelandscapeismadeupofasinglepatch,theLPIwillequal100.Asthesizeofthelargestpatchdecreases,theLPIapproaches0.

MeanPatchSize（MPS）

Averagepatchsize.

Example:

MeanPatchSizeofConiferPatches（ClassLevel）

MPS=（359047.844+139531.484...+65819.984）/4

MPS=17.42hectares

Example:

MeanPatchSizeofPatches（LandscapeLevel）

MPS=（46872.719+359047.844+...+62432.574）/14

MPS=13.15hectares

MedianPatchSize（MedPS）

Themiddlepatchsize,or50thpercentile.

Example:

MedianPatchsizeofConiferPatches（ClassLevel）

MedPS=13.22hectares

Example:

MedianPatchsizeofallpatches（LandscapeLevel）

MedPS=7.59hectares

PatchSizeStandardDeviation（PSSD）

StandardDeviationofpatchareas.

Example:

PatchSizeStandardDeviationofConiferPatches（ClassLevel）

PSSD=11.05hectares

Example:

PatchSizeStandardDeviationofallpatches（LandscapeLevel）

PSSD=9.51hectares

PatchSizeCoefficientofVariance（PSCoV）

Coefficientofvariationofpatches.

Example:

CoefficientofVariationofConiferpatches（ClassLevel）

PSCoV=PSSD/MPS=（11.05hectares/17.42hectares）*100=63

Example:

CoefficientofVariationofallpatches（LandscapeLevel）

PSCoV=（9.51hectares/13.15hectares）*100=72

TotalEdge（TE）

Perimeterofpatches.

Example:

TotalEdgeConifer（ClassLevel）

TE=Sumofperimeterofallconiferpatches.

TE=10858.88metres

Unitsareexpressedinnativemapsunits.

Example:

TotalEdgeallpatches（LandscapeLevel）

TE=Sumofperimeterofallpatches

TE=28607.27metres

Important

Inthecaseofvectorlayers（themes）,edgecalculationsincludealltheedgeonthelandscapeincludingboundaryedge.Thecontrastedweightededgefeatureallowsedgeweightattheboundariestobesettozero.Inthecaseofraster（grid）layers（themes）,edgecalculationsdonotincludetheedgesthatsurroundthelandscapeboundaryedgeoranyinterioredgesthatincludepixelsclassifiedasNoData.

EdgeDensity（ED）

Amountofedgerelativetothelandscapearea.

Example:

EdgeDensityConifer（ClassLevel）

ED=TE/TLA

ED=10858.88metres/184.11hectares=58.98metres/hectare

Example:

EdgeDensityofallPatches（LandscapeLevel）

ED=28607.27metres/184.11hectares=155.38metres/hectare

MeanPatchEdge（MPE）

Averageamountofedgeperpatch.

Example:

MeanPatchEdgeConifer（ClassLevel）

MPE=TE/NumP

MPE=10858.88metres/4patches=2714.72metres/patch

Example:

MeanPatchEdgeallPatches（LandscapeLevel）

MPE=TE/NumP

MPE=28607.27metres/14patches=2043.38metres/patch

ContrastedWeightedEdgeDensity（CWED）

CWEDisameasureofdensityofedgeinalandscape（metresperhectare）withauser-specifiedcontrastweight.

CWEDisequalto0whenthereisnoedgeinthelandscape,inotherwordsthewholelandscapeandit'sborderaremadeupofasinglepatch.It'svalueincreasesastheamountofedgeinthelandscapeincreasesand/orastheuserincreasesthecontrastweight.

LandscapeShapeIndex（LSI）

LSIisthetotallandscapeboundaryandalledgewithintheboundarydividedbythesquarerootofthetotallandscapearea（squaremetres）andadjustedbyaconstant（circularstandardforvectorlayers,squarestandardforrasters）.TheLSIwillincreasewithincreasinglandscapeshapeirregularityorincreasingamountsofedgewithinthelandscape.

DoubleLogFractalDimension（DLFD）

DLFDisameasureofpatchperimetercomplexity.Itnears1whenpatchshapesare'simple',suchascirclesorsquaresanditapproaches2aspatchshapeperimetercomplexityincreases.

MeanPerimeter-AreaRatio（MPAR）

ShapeComplexity.

Example:

Meanperimeter-arearatioConifer（ClassLevel）

MPAR=Sumofeachpatchesperimeter/arearatiodividedbynumberofpatches.

MPAR=（132m/ha+112m/ha+201m/ha+84m/ha）/4patches

MPAR=182metres/hectare

Example:

Meanperimeter-arearatioallpatches（LandscapeLevel）

MPAR=（200m/ha+132m/ha+...+175m/ha）/14patches

MPAR=185metres/hectare

MeanShapeIndex（MSI）

ShapeComplexity.

MSIisequalto1whenallpatchesarecircular（forpolygons）orsquare（forrasters（grids））anditincreaseswithincreasingpatchshapeirregularity.

MSI=sumofeachpatch'sperimeterdividedbythesquarerootofpatcharea（inhectares）foreachclass（whenanalyzingbyclass）orallpatches（whenanalyzingbylandscape）,andadjustedforcircularstandard（forpolygons）,orsquarestandard（forrasters（grids））,dividedbythenumberofpatches.

AreaWeightedMeanShapeIndex（AWMSI）

AWMSIisequalto1whenallpatchesarecircular（forpolygons）orsquare（forrasters（grids））anditincreaseswithincreasingpatchshapeirregularity.

AWMSIequalsthesumofeachpatch'sperimeter,dividedbythesquarerootofpatcharea（inhectares）foreachclass（whenanalyzingbyclass）orforallpatches（whenanalyzingbylandscape）,andadjustedforcircularstandard（forpolygons）,orsquarestandard（forrasters（grids））,dividedbythenumberofpatches.ItdiffersfromtheMSIinthatit'sweightedbypatchareasolargerpatcheswillweighmorethansmallerones.

MeanPatchFractalDimension（MPFD）

ShapeComplexity.

Meanpatchfractaldimension（MPFD）isanothermeasureofshapecomplexity.Meanfractaldimensionapproachesoneforshapeswithsimpleperimetersandapproachestwowhenshapesaremorecomplex.

AreaWeightedMeanPatchFractalDimension（AWMPFD）

ShapeComplexityadjustedforshapesize.

Areaweightedmeanpatchfractaldimensionisthesameasmeanpatchfractaldimensionwiththeadditionofindividualpatchareaweightingappliedtoeachpatch.Becauselargerpatchestendtobemorecomplexthansmallerpatches,thishastheeffectofdeterminingpatchcomplexityindependentofitssize.Theunitofmeasureisthesameasmeanpatchfractaldimension.

MeanNearestNeighbor（MNN）

Measureofpatchisolation.

Thenearestneighbordistanceofanindividualpatchistheshortestdistancetoasimilarpatch（edgetoedge）.Themeannearestneighbordistanceistheaverageofthesedistances（metres）forindividualclassesattheclasslevelandthemeanoftheclassnearestneighbordistancesatthelandscapelevel.

InterspersionJuxtapositionIndex（IJI）

Measureofpatchadacency.

Approacheszerowhenthedistributionofuniquepatchadjacenciesbecomesunevenand100whenallpatchtypesareequallyadjacent.

Interspersionrequiresthatthelandscapebemadeupofaminimumofthreeclasses.Attheclasslevelinterspersionisameasureofrelativeinterspersionofeachclass.Atthelandscapelevelitisameasureoftheinterspersionoftheeachpatchinthelandscape.

MeanProximityIndex（MPI）

Measureofthedegreeofisolationandfragmentation.

Meanproximityindexisameasureofthedegreeofisolationandfragmentationofapatch.MPIusesthenearestneighborstatistic.Thedistancethresholddefaultis1,000,000.IfMPIisrequiredatspecificdistances,selectSetMPIThresholdfromthemainPatchpull-downmenuandenterathresholddistance.

BothMNNandMPIusethenearestneighborstatisticofsimilarpolygonsintheiralgorithm.OccasionallyablankorzerowillbereportedinMNNandMPIfields.Thishappenswhenonepolygonvertextouchesanotherpolygonsborderbutthetwosimilarpolygonsdonotshareacommonborder.Whenthishappensamanualedit（move）ofthetouchingvertexwillcorrecttheprobleminthelayer（theme）.Thisproblemwillnothappenwhenanalyzingraster（grid）layers（themes）.

Shannon'sDiversityIndex（SDI）

Measureofrelativepatchdiversity.

Shannon'sdiversityindexisonlyavailableatthelandscapelevelandisarelativemeasureofpatchdiversity.Theindexwillequalzerowhenthereisonlyonepatchinthelandscapeandincreasesasthenumberofpatchtypesorproportionaldistributionofpatchtypesincreases.

Simpson'sDiversityIndex（SIDI）

Measureofrelativepatchdiversity.

Si