Establishment of orthophoto map using Lidar technology combined with digital photography at Tan Son Nhat Airport, Ho Chi Minh City

Abstract

This article presents a detailed process for generating orthophoto maps using LiDAR technology alongside digital photography derived from uncorrected LiDAR data, also referred to as raw data. The process consists of five main steps: 1. Selection and establishment of control points: Choose and establish control points for precise georeferencing; 2. Planning and execution of LiDAR scanning flights: Plan the flight path and parameters for efficient data collection; 3. Generation of raw point cloud: Following data collection, the raw point cloud is generated, forming the basis for subsequent processing and analysis; 4. Orientation and adjustmentof the point cloud data to correct distortions; 5. Creation of an orthophoto map and accuracy evaluation: In the final phase, increase image control density to produce orthogonal maps and evaluate accuracy.This methodology was applied to create orthophoto maps of the Tan Son Nhat airport area in Ho Chi Minh City, utilizing Trimble's Inpho software suite. The research results show that the discrepancies in X, Y coordinates and height (h) between the model values and the measured values for the 25 checkpoints have maximum values of 0.149 m, 0.167 mand 0.169 m, and minimum values of 0.004 m, 0.005 m, and 0.002 m, respectively. The difference in the position coordinates and height of the orthophoto map for the Tan Son Nhat Airport area is less than 10 cm.With images having a resolution of 0.1 m, the coordinates and heights of the orthophoto map have small deviations. Therefore, the orthophoto map in this study has high accuracy, ensuring the creation of maps at a scale of 1:1000 and smaller scales in the experimental area