2.3.AccuracyandPrecision主講人：LiSimengThislessoncontains3parts.thetermsofAccuracyandPrecisiontheknowledgeofAccuracyandPrecisionthesentenceanalysis01WhatIsGeomaticsCONTENTS目錄PARTONEWhatIsGeomatics01WhatIsGeomatics(1）thetermsofAccuracyandPrecisionPrecise精確Imprecise不精確Accurate準(zhǔn)確Inaccurate不準(zhǔn)確In和im都表示否定，那么什么時候用in，什么時候用im呢。WhatIsGeomatics(1）thetermsofAccuracyandPrecision這里需要給大家拓展一下in-及im-，il-，ir-都是表示否定的前綴，表示"不、無、非"等否定意義。1.字母b，m，p開頭的形容詞，其否定前綴為im-。例如：imbalance（不平衡的）immoral（不道德的）impossible（不可能的）。2.以字母l開頭的單詞用il-；以字母r開頭的單詞用ir-。例如：illegal（不合法的）illogical（不合邏輯的）irregular（不規(guī)則的）irrelative（無關(guān)系的）。3、以其他字母開頭的為in-。例如：inhuman（不人道的）injustice（不公平的）inseparable（不可分的）incorrect（不正確的）。WhatIsGeomatics(1）thetermsofAccuracyandPrecisionRefinementn.（精細(xì)的）改進(jìn)，改善，精制Performancen.表現(xiàn)Uniformityn.一致性Scattern.離差，散射Bentn.傾向，歪Marksmann.射手methodology詞根method,方法，-logy,學(xué)說n.方法，原則WhatIsGeomatics(1）thetermsofAccuracyandPrecisionAdjustmentn.調(diào)整Unavoidable詞根avoidv.避免?-able形容詞詞綴表示有能力的avoidableadj.可避免的un-前綴表否定，Unavoidable表示

不可避免的indexn.指數(shù)closure的詞根close,關(guān)閉，-ure,名詞后綴

意思為：停業(yè)，關(guān)閉；倒閉Sophisticatedadj.

先進(jìn)的，精密的；水平高的Consumev.消耗，消費；吃Consumingadj.消耗性的time-consuming消耗時間的WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

Precision:Thedegreeofrefinementintheperformanceofanoperation,orthedegreeofperfectionintheinstrumentsandmethodsusedtoobtainaresult,oranindicationoftheuniformityorreproducibilityofaresult.WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

Figure1showsuniformityachievedbythemarksmanwhoisskilledbyverysmallscatter.Itillustratestheexcellentprecision.WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

Accuracy:Thedegreeofconformityofafinalmeasuredvalue,withrespecttothetruevalueasdefinedbyacceptedstandard(the“truth”).

WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

Figure2showstheshotsachievebythemarksmanwithawidescatter.Itillustratesthatthebentsightisnowcorrected,ie.thesystematicerrorsareminimized,andthemarksmanhasapproachedthe“truth"althoughwithoutgreatprecision.Itmaybethatthemarksmanwillneedtochangetheequipmentormethodologyusedtoobtaintheresultifagreaterdegreeofprecisionisrequired,ashehasreachedthelimitationsassociatedwithhisequipmentandmethodology.WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

InFigure3,theshotsareclusterednearthecenterofthetarget.Itrepresentsresultsindicatingbothaccuracyandprecision.Inthiscase,themarksmanhasprobablymadeoneofthesystematicadjustmentsthatwereindicatedbyhisattainmentofprecisionwithoutaccuracy.WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

theanalysisofprecisionandaccuracy(1)Scatterisan“indicatorofprecision”;thewiderthescatterofasetofresultsaboutthemean,thelessreliabletheywillbecomparedwithresultshavingasmallscatter.(2)Precisionmustnotbeconfusedwithaccuracy;theformerisarelativegroupingwithoutregardtothenearnesstothetruth,whilstthelatterdenotesabsolutenearnesstothetruth.WhatIsGeomatics(2）theknowledgeoftheAccuracyandPrecision

(3)Precisionmayberegardedasanindexofaccuracyonlywhenallsourcesoferror,otherthanrandomerrors,havebeeneliminated.Anexamplethatexplainsthedifferencebetweenprecisionandaccuracybetterthananyotherinsurveyinghastodowitherrorofclosureintraversing.WhatIsGeomatics(3）thesentenceanalysisPerhapstheeasiestwaytoillustratethedifferencebetweenaccuracyandprecisionistousetheanalogyofamarksman,towhomthe“truth"representsthebull's-eye.本句的主干部分為theeasiestwayisusetheanalogyofamarksman，其后，緊跟一個介詞+關(guān)系代詞引導(dǎo)的定語從句，即towhom引導(dǎo)的定語從句。Whom指代makrsman，towhom引導(dǎo)的定語從句修飾限定先行詞theanalogyofamarksman,①或許闡明準(zhǔn)確度和精度兩者區(qū)別最簡單的方法是用射手(射擊)來進(jìn)行類比,這里“真值”代表靶心。WhatIsGeomatics(3）thesentenceanalysisWiththeknowledgegainedbyobservationoftheresults,themarksmancarapplyasystematicadjustment(aimhigherandtotheleftofhisintendedtarget,orhavehisequipmentadjusted)toachievemoreaccurateresultsinadditiontotheprecisionthathismethodologyandequipmenthavealreadyattained.本句主干為themarksmancarapplyasystematicadjustmenttoach