Positional accuracy analysis of orthophotos produced by photogrammetric methods on different surface types and different heights

UAV photogrammetry has been a verycurrentstudytopicforbothGeomaticEngineeringandotherdisciplines in recentyears. Especiallyforlargeareas, it has become a greatmethod of fastaccesstoaccurate data, thankstoitsdetailedmeasurement. Orthophotos (orthosaic), one of theoutputproducts of UAV photogrammetry, areusuallytaken as two-dimensional; being a baseforprojectsandplans, monitoringthechanges in a certain time interval on thearea, creating a baseimageforvectordatabases, etc. usedforsuchpurposes. It can also be resizedtofacilitatethree-cellvisualinterpretation. Replacementenclosuresaccordingto data obtainedfromgeometricshapes of orthophotosproducedfromtheseframes. Thegrowth of geometricdesignwillincreasethedetection of detailclasses as well as increasetheprocessingload on the hardware. Forthisreason, it will be suitablefortheoutput of themostaccurateparametersaccordingtotheneedsduringtheproduction of orthophotos. Locationmodifiersarealsoimportant, downtothegeometricenclosuresfound in prisons. Thestudywascarriedout on an area of 20.2 hectareswithdifferentsurfacetypes in thecentraldistrict of Adıyaman province. 17 pointsaremarkedto form theworkareaentranceGround Control Points (GCP) and Analysis Points (AN). Fourflightswerecarriedoutwiththe UAV at 100 and 200 metersflightaltitudes, withcameraanglesadjustedverticallyandobliquely, andthe horizontal andverticalpositions of the YKN observerandflighttype on the data wereexamined. As a resultwith0.07 Rootmeansquarevalue of thestatisticalanalyzes, theresultwiththeleasterrorwasobtainedbyadjustingthephotostakenwith nadir cameraanglefrom a height of 100 meterswiththe GCP valueshomogeneouslydistributedoverthefieldwascalculated. The resul twith0.12 Rootmeansquarevaluewiththehighesterrorwasobtainedbyadjustingthephotostakenwith a verticalcameraanglefrom a height of 200 meterswiththe YKN valuesdistributed in the form of a verticalline on thefieldwascalculated. Theseresultsshowthat UAV photogrammetryproduces data withveryhighaccuracy in terms of locationaccuracyandtheaccuracy can be furtherincreasedwithvariableparameterselections.