Pemetaan sungai berskala besar menggunakan fotogrametri jarak dekat dan sistem pesawat udara tanpa pemandu

Abstract

Recently the technology of unmanned aerial vehicle (UAV) system has developed rapidly. Indirectly, it has increased the application of UAV for various applications especially in the field of close range photogrammetry and mapping application. This method can be used as an alternative to large scale mapping application because it has many advantages in term of cost, time and weather constraint. However, the accuracy of UAV data in the field of mapping is questionable due to it less ventured. Therefore the aim of this study is to evaluate the accuracy of close range photogrammetric method and UAV system in mapping river at large scale. In this study, the aerial photographs of river model and Danga River in Johor Bahru are acquired using digital camera attached to the UAV. The aerial photo for mapping of river model is acquired at the height of three (3) metre and the aerial photo of Danga River is acquired at the height of 300 metre. The acquired aerial photographs were processed using Agisoft Photoscan Profesional software to produce photogrammetric products such as orthomosaic, digital elevation model (DEM) and contour line. Every product is evaluated for accuracy assessment using Root Mean Squared Error (RMSE) equation. RMSE X and RMSE Y values for case study of mapping river model are X= ±0.008 metre and Y= ±0.035 metre respectively. Meanwhile, planimetric RMSE value is XY= ±0.036 metre. The RMSE value of height for mapping river model is Z= ±0.322 metre. For case study of mapping Danga River, the RMSE X and RMSE Y values obtained are X= ±0.048 metre dan Y= ±0.065 metre respectively. The planimetri value is XY= ±0.080 metre dan the height RMSE value is Z= ±0.677 meter. Based on the RMSE values obtained for both case study, the orthomosaic produced is accurate because the RMSE value is less than one (1) meter. DEM and contour line for both case studies are also accurate because the RMSE value is small which less than one (1) meter is. As conclusion, close range photogrammetric method and UAV system can be used for mapping large scale river.