Effects of dems from different resolutions in deriving stream networks threshold values and morphometric analysis
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Date
2018-07-01
Authors
Nor Azura Ishak
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Abstract
The use of Digital Elevation Model on the watershed survey has been accepted and applied in various applications involving hydrological studies. However, there is a challenge to determine topographic surface accuracy in the areas where the use of ground-based topographic surface studies takes a long time. Therefore, this research was conducted to study and determine the height accuracy from multiple digital models over network of streams. The study has determined the height accuracy rating of the digital elevation model from various sources and different resolutions. DEM sources from SRTM, ASTER, and NEXTMap World 30 and topographic maps were used to assess and compare the accuracy. The Root Mean Square Error (RMSE) was acquired in the vertical accuracy assessment. The results show that the RMSE value for SRTM is ± 8.15 m, ± 8.68 m for ASTER, and ± 7.98 m for NEXTMap World 30, are within the permissibility allowed by the USGS. Subsequently, the river flow study on the SRTM 30 m establishes a similar result with the study performed by the Malaysian Drainage and Drainage Department. Meanwhile, the analysis reveals that the drainage network from SRTM 30 m with threshold values of 40 was closest to the referenced drainage. The result has signifies the most appropriate values for an effective stream threshold network to be considered suitable for future river sub-basin analysis.