Accuracy of the digital terrain model (DTM), considering the number of ground support points in a photogrammetric survey applied on the Pampa Grande-Tablazos highway, Chiclayo Province

Abstract

The present study evaluates the accuracy of the digital terrain model (DTM) regarding the number of control points (“P.A.”) in a photogrammetric survey with a drone, applied on the road between Pampa Grande and Tablazos, with 8917 meters of development, in the province of Chiclayo, Peru. The “P.A.” number determines the accuracy of each processed model, from the photo orientation phase; affecting the other deliverables generated, such as the DSM (digital surface model), DTM and orthophotography. It started with 0 P.A. in Model No. 1, up to 141 P.A. in Model No. 15. The number of check points (“P.C.”) that were used to verify the precision was 27. After processing the data with statistical software, it is concluded that, for the design of the photogrammetric survey project and the methodology followed, 7 “P.A.”/km are needed to achieve accuracy of the DTM in valid margins. Of the processed models, they are valid from Model No. 8. From this model the "surface" was generated starting from the DTM, in Autodesk Civil3D, where the contour lines were created with excellent detail, remaining as a canvas for the design of civil projects.