《数字测图》课件-2.1图根平面控制

数字测图DigitalMappingPlanimetricRootControl图根平面控制目录CONTENTS全站仪图根平面控制测量TotalstationplanimetricrootcontrolmeasurementRTK图根平面控制测量RTKplanimetricrootcontrolmeasurement测站点增补Surveypointsupplementation当测区高级控制点的密度一般不能满足大比例尺数字测图的需求时，需加密适当数量的图根控制点（又称图根点），直接供测图使用，这项工作称为图根控制测量。Whenthedensityoftheadvancedcontrolpointsinthesurveyareacannotgenerallymeettherequirementsoflarge-scaledigitalmapping,itisnecessarytoencryptanappropriatenumberofrootcontrolpoints(alsoknownasrootpoints)thatcanbedirectlyusedformapping.Thisworkiscalledmappingcontrolsurvey.图根控制测量Mappingcontrolsurvey0102Totalstationtraversemeasurement全站仪导线测量RTKGPS测量RTKGPSmeasurementRootsurveylines图根导线Roottriangles图根三角Radiationpointmethod辐射点法交会测量One-stepmeasurementmethod一步测量法01Totalstationtraversemeasurement全站仪导线测量Intersectionmeasurement因地形限制图根导线无法附合时，可布设支导线。支导线不多于四条边，长度不超过450m，最大边长不超过160m。边长可单程观测一测回。水平角观测首站应连测两个已知方向，观测一测回，其固定角不符值不应超过±40″；其他站水平角观测一测回。全站仪图根平面控制测量TotalstationplanimetricrootcontrolmeasurementIftheplanimetricsurveylinecannotbeclosedduetoterrainrestrictions,asupportsurveylinecanbesetup.Thenumberofsidesofthesupportsurveylineshouldnotexceedfour,andthelengthshouldnotexceed450m,withamaximumsidelengthof160m.Thesidelengthcanbeobservedforonetraverse.Thehorizontalangleobservationofthefirststationshouldbemeasuredfortwoknowndirections,withonetraverse,andthefixedangledifferenceshouldnotexceed±40".Otherstationsshouldmeasureonetraverseforhorizontalangleobservation.全站仪图根平面控制测量Totalstationplanimetricrootcontrolmeasurement图根导线可采用近似平差。Theplanimetricsurveylinecanbeprocessedbyapproximateadjustment.计算时角度值取至秒，边长和坐标取至毫米。Theanglevaluesareroundedtoseconds,thesidelengthsandcoordinatesareroundedtomillimeters.Radiationpointmethod辐射点法辐射点法就是在某一通视良好的等级控制点上，用极坐标测量方法，按全圆方向观测方式依次测定周围几个图根控制点。Radiationpointmethodistomeasureseveralrootcontrolpointsaroundacertaingoodvisibilityclasscontrolpointusingthepolarcoordinatemeasurementmethodinafullcircleobservationmanner.Theadvantagesofradiationpointmethod辐射点法的优点12图根点只需与测站通视，易于选择有利于测图的最佳位置。Therootpointsonlyneedtobevisiblefromthesurveystation,makingiteasiertochoosetheoptimalpositionformapping.无需平差计算，可直接获得坐标，只要采取一定的措施，相对于测站的点位精度可控制在5cm之内，常用于以地形为主的数字测图。Noadjustmentcalculationisrequired,andcoordinatescanbeobtaineddirectly.Aslongascertainmeasuresaretaken,thepositionaccuracyofthepointsrelativetothesurveystationcanbecontrolledwithin5cm,whichiscommonlyusedindigitalmappingbasedonterrain.Theadvantagesofradiationpointmethod辐射点法的优点为了保证图根点的可靠性，通常需要另选定向点，再对各图根控制点进行第二次观测，取两次观测值的均值作为图根控制点的最终坐标。Inordertoensurethereliabilityoftherootpoints,asecondobservationofeachrootcontrolpointisusuallyrequired,andthemeanvalueofthetwoobservationvaluesistakenasthefinalcoordinateoftherootcontrolpoint.One-stepmeasurementmethod一步测量法一步测量法就是在图根导线选点、埋石以后，利用全站仪将图根导线测量与碎部测量同时作业，在测定导线后，提取各条导线测量数据进行导线平差，而后再按新坐标对碎部点进行坐标重算，这样在一定程度上可以提高外业工作效率。One-stepmeasurementmethodisamethodthat,aftertherootsurveylinepointselectionandstoneburial,usestotalstationtosimultaneouslycarryoutrootsurveylinemeasurementandfragmentarymeasurement.Afterdeterminingthesurveyline,extractthedataofeachsurveylinemeasurementandperformsurveylineadjustment,andthencalculatethecoordinatesofthefragmentarypointsaccordingtothenewcoordinates.Thiscanimprovetheefficiencyoffieldworktoacertainextent.RTK图根平面控制测量RTKplanimetricrootcontrolmeasurement快速静态定位模式要求GPS接收机在每一流动站上静止的进行观测。在观测过程中，同时接收基准站和卫星的同步观测数据，实时解算整周未知数和用户站的三维坐标，如果解算结果的变化趋于稳定，且其精度已满足设计要求，便可以结束实时观测。RapidstaticpositioningmoderequiresGPSreceiverstoobservestaticallyateachmobilestation.Duringtheobservationprocess,GPSdataisreceivedsynchronouslyfromthereferencestationandsatellites,andtheintegerunknownandthree-dimensionalcoordinatesoftheuserstationarecalculatedinrealtime.Iftheresultsofthecalculationbecomestableandtheaccuracymeetsthedesignrequirements,thereal-timeobservationcanbeended.01快速静态定位测量RapidstaticpositioningmeasurementRTK图根平面控制测量RTKplanimetricrootcontrolmeasurement01快速静态定位测量Rapidstaticpositioningmeasurement速度快Fastspeed精度高Highaccuracy效率高HighefficiencyRTK图根平面控制测量RTKplanimetricrootcontrolmeasurement在采集图根点坐标时，针对某一具体型号的RTK总需要满足一定的采集精度指标，一般要求锁定卫星颗数大于6，精度因子小于4，解算状态必须是固定解状态，水平精度HRMS小于2cm，高程精度小于3cm，只有当这些指标满足的情况下，方可实施图根控制。TheothermethodisRTKreal-timedynamicmeasurement.Whencollectingthecoordinatesoftherootcontrolpoint,itisnecessarytomeetcertainaccuracyindicatorsforaspecificmodelofRTK.Generally,itisrequiredthatthelockedsatellitenumberisgreaterthan6,theaccuracyfactorislessthan4,thesolutionstatusmustbeafixedsolutionstate,thehorizontalprecisionHRMSislessthan2cm,theelevationprecisionislessthan3cm,andonlywhentheseindicatorsaremet,cantherootcontrolbeimplemented.02RTK实时动态测量法RTKreal-timedynamicmeasurementRTK图根平面控制测量RTKplanimetricrootcontrolmeasurement02RTK实时动态测量法RTKreal-timedynamicmeasurementRTK实时动态定位测量的图根点能