Ishak, Nor Azura (2018) Effects Of Dems From Different Resolutions In Deriving Stream Networks Threshold Values And Morphometric Analysis. Masters thesis, Universiti Sains Malaysia.
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Abstract
Penggunaan Model Ketinggian Berdigit (DEM) terhadap kajian kawasan tadahan air telah diterima dan digunakan dalam pelbagai aplikasi yang melibatkan kajian hidrologi. Walau bagaimanapun, terdapat cabaran terhadap penentuan ketepatan permukaan topografi sesuatu kawasan dimana penggunaan kajian berasaskan lapangan dalam menentukan permukaan topografi mengambil masa yang agak lama. Oleh itu,kajian ini telah dijalankan untuk mengkaji dan menilai ketepatan ketinggian pelbagai model berdigit terhadap rangkaian aliran sungai. Kajian ini telah mengenalpasti penarafan ketepatan ketinggian model ketinggian berdigit daripada pelbagai sumber dan resolusi yang berbeza. Sumber DEM daripada SRTM, ASTER, NEXTMap World 30 dan peta topografi telah digunakan dalam kajian sebagai penilaian dan perbandingan ketepatan. Ralat Punca Min Kuasa Dua (RMSE) diperolehi dalam penilaian ketepatan tegak. Hasil kajian menunjukkan nilai RMSE untuk SRTM ialah ± 8.15 m, ± 8.68 m untuk ASTER, dan ± 7.98 m untuk NEXTMap World 30, telah berada dalam kebolehtelapan yang dibenarkan oleh USGS. Seterusnya, kajian aliran sungai menggunakan SRTM 30 m menunjukkan hasil yang serupa dengan kajian yang dilakukan oleh Jabatan Pengairan dan Saliran Malaysia. Sementara itu, hasil analisis membuktikan bahawa rangkaian saliran dari SRTM 30 m dengan nilai ambang 40 adalah paling hampir dengan saliran rujukan. Hasil kajian telah memberi petunjuk kepada nilai-nilai ambang yang berkesan dan sesuai untuk analisis rangkaian aliran sub-lembangan sungai masa hadapan. _______________________________________________________________________________________________________ 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.
| Item Type: | Thesis (Masters) |
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| Additional Information: | Full text is available at http://irplus.eng.usm.my:8080/ir_plus/institutionalPublicationPublicView.action?institutionalItemId=4683 |
| Subjects: | T Technology T Technology > TA Engineering (General). Civil engineering (General) > TA1-2040 Engineering (General). Civil engineering (General) |
| Divisions: | Kampus Kejuruteraan (Engineering Campus) > Pusat Pengajian Kejuruteraan Awam (School of Civil Engineering) > Thesis |
| Depositing User: | Mr Mohd Jasnizam Mohd Salleh |
| Date Deposited: | 12 Jun 2019 08:43 |
| Last Modified: | 12 Jun 2019 08:43 |
| URI: | http://eprints.usm.my/id/eprint/44565 |
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