Assessing the accuracy of open‑source digital elevation models for the geomorphological analysis of very small islands of Indonesia
artículo original
Fecha
2023Autor
Quesada Román, Adolfo
Mutaqin, Bachtiar W.
Nadafa Isnain, Muhammad
Aris Marfai, Muh
Fatchurohman, Hendy
Quesada Román, Adolfo
Khakhim, Nurul
Metadatos
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Digital elevation models (DEMs) are used for many geosciences studies; hence, their accuracy is essential. Throughout the
world, there are many small islands of various sizes and densities; hence, it is important to assess the DEM accuracy on very
small islands since DEMs serve as the major data source for many investigations, particularly in geomorphology, land-use
planning, and disaster management. Therefore, this paper aims to validate the accuracy of an open-source Indonesian DEM
(DEMNAS) in the very small islands of Karimunjawa–Indonesia. Validation was conducted by comparing elevation values
from DEMNAS to the true elevation values in four very small islands in Karimunjawa, namely Cemara Besar, Cemara Kecil,
Menjangan Besar, and Menjangan Kecil. The true elevation values were obtained by orthorectification of aerial imagery using
a DJI Mavic Air-2 Unmanned Aerial Vehicle (UAV). The orthorectification came from ground control points (GCP) from
the geodetic Global Positioning System (GPS). In the study area, fourteen GCP were erected; for more significant coverage,
they were placed along the edges of the very small islands. After that, Agisoft software analyzed the images to produce a
DEM using GCP orthorectification. Based on 280 sampling points, we applied a root-mean-square error (RMSE) to calculate
elevation errors, and we performed the linear error 90% (LE90) calculation to judge the average errors with the 90% threshold
of absolute values of discrepancies. The DEMNAS RMSE and LE90 calculation results in the Karimunjawa archipelago
were 6.33 m and 10.45 m, respectively. Citing Regulation Number 15 of the Head of the Indonesian Geospatial Information
Agency of 2014 concerning Technical Guidelines for Basic Map Accuracy, DEMNAS with 10.45 m LE90 can be utilized
for producing geomorphological maps with scales of 1:25,000 or smaller. However, detailed geomorphological mapping of
a very small island (less than 100 km2)
needs better DEM data that is usually produced using aerial photogrammetry. Using
UAVs for DEMs creation may benefit small island developing states (SIDS) worldwide.
External link to the item
10.1007/s12518-023-00533-8Colecciones
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