Aulia, Selfina Rifqi Marfa (2025) Pemodelan Geoid Gravimetrik Pulau Sulawesi: Pendekatan Fast Fourier Transform dengan Kombinasi Data Gayaberat Airborne, Terestris, dan Model SGG-UGM2. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Geoid gravimetrik merupakan representasi permukaan aktual bumi yang berguna dalam penentuan tinggi orthometrik bersifat akurat melalui transformasi dari tinggi geometrik. Pada penelitian ini, dilakukan pemodelan geoid gravimetrik Pulau Sulawesi menggunakan pendekatan 1D-FFT berbasis metode Remove-Compute-Restore (RCR). Data yang digunakan sebagai model anomali dan undulasi menggunakan model SGG-UGM2 dengan variasi derajat harmonik maksimum yaitu 180, 315, 360, dan 720. Selain itu, menggunakan data free-air anomaly (FAA) yang mencakup FAA airborne dan terestris serta data fill-in daratan berupa GGMPlus dan lautan berupa DTU17. Data ketiga berupa data topografi dari dua jenis model elevasi, yaitu SRTM15+ dengan resolusi 15” dan SRTM kombinasi yang tediri dari hasil gabungan dari SRTM Global 30 meter (GL1) dengan resolusi 1” untuk daratan dan SRTM15+ untuk lautan. Model geoid yang dihasilkan adalah delapan variasi yang didasarkan pada kombinasi degree harmonik dan data topografi. Proses fitting pada hasil undulasi gravimetrik dilakukan menggunakan data GNSS-leveling dengan indeks titik ganjil. Sementara untuk validasi menggunakan titik GNSS-leveling indeks genap. Proses validasi dikategorikan menjadi tiga bagian menggunakan data validasi keseluruhan antara utara dan selatan, data validasi Sulawesi Utara, dan data validasi Sulawesi Selatan. Penggunaan validasi keseluruhan menghasilkan ketelitian paling baik yaitu variasi lima dengan kriteria degree 180 dan SRTM kombinasi dengan standar deviasi 5,762 cm. Terbaik kedua adalah variasi satu dengan degree 180 serta SRTM15+ dengan standar deviasi sebesar 5,848 cm. Dan untuk variasi terburuk adalah variasi empat dengan degree 720 dan SRTM15+ dengan nilai sebesar 6,129 cm. Penggunaan validasi Sulawesi Utara menghasilkan ketelitian paling baik pada variasi tiga dan satu dengan ketelitian 6,832 cm dan 6,833 cm. Kedua variasi tersebut menggunakan SRTM15+, namun pada variasi tiga menggunakan degree 360 sedangkan variasi satu menggunakan degree 180. Sedangkan, ketelitian terburuk terdapat pada variasi delapan sebesar 7,126 cm dengan kriteria degree 720 dan SRTM kombinasi. Penggunaan validasi Sulawesi Selatan menghasilkan ketelitian paling baik pada variasi lima dan satu dengan ketelitian 6,832 cm dan 6,833 cm. Ketelitian terburuk terdapat pada variasi dua sebesar 6,441 cm dengan kriteria degree 315 dan SRTM15+.
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The gravimetric geoid represents the actual surface of the Earth and is useful for accurately determining orthometric heights through the transformation of geometric heights. In this study, gravimetric geoid modeling of Sulawesi Island was carried out using a 1D-FFT approach based on the Remove-Compute-Restore (RCR) method. The anomaly and undulation models used in this study are based on the SGG-UGM2 model with varying maximum harmonic degrees of 180, 315, 360, and 720. In addition, free-air anomaly (FAA) data were used, including airborne and terrestrial FAA, as well as fill-in data consisting of GGMPlus for land areas and DTU17 for ocean areas. The third dataset comprises topographic data derived from two elevation models: SRTM15+ with a 15” resolution, and a combined SRTM model consisting of SRTM Global 30-meter (GL1) with 1” resolution for land and SRTM15+ for sea areas. Eight geoid models were produced based on combinations of harmonic degrees and topographic datasets. The fitting process for gravimetric geoid undulations was conducted using GNSS-leveling data with odd-indexed points, while validation was performed using even-indexed GNSS-leveling points. The validation process was categorized into three parts full-area validation combining northern and southern regions, Northern Sulawesi validation, and Southern Sulawesi validation. For the full-area validation, the best accuracy was achieved by variation five, which used degree 180 and the combined SRTM model, yielding a standard deviation of 5,762 cm. The second-best result was from variation one, using degree 180 and SRTM15+, with a standard deviation of 5,848 cm. The poorest result came from variation four, using degree 720 and SRTM15+, with a value of 6,129 cm. For Northern Sulawesi validation, the best accuracy was achieved in variations three and one, with standard deviations of 6,832 cm and 6,833 cm, respectively. Both used SRTM15+, although variation three used degree 360, while variation one used degree 180. The lowest accuracy was found in variation eight, with a standard deviation of 7,126 cm, using degree 720 and the combined SRTM model. For Southern Sulawesi validation, the best accuracy was also achieved in variations five and one, with standard deviations of 6,832 cm and 6,833 cm, respectively. The poorest result was found in variation two, which used degree 315 and SRTM15+, with a value of 6,441 cm.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Degree, Fast Fourier Transform, Geoid Gravimetrik, Remove-Compute-Restore, SGG-UGM2, SRTM15+, SRTM Kombinasi |
| Subjects: | G Geography. Anthropology. Recreation > G Geography (General) > G109.5 Global Positioning System G Geography. Anthropology. Recreation > G Geography (General) > G70.217 Geospatial data G Geography. Anthropology. Recreation > G Geography (General) > G70.5.I4 Remote sensing G Geography. Anthropology. Recreation > GA Mathematical geography. Cartography > GA139 Digital Elevation Model (computer program) Q Science > QC Physics > QC20.7.F67 Fourier transformations |
| Divisions: | Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29202-(S1) Undergraduate Thesis |
| Depositing User: | Selfina Rifqi Marfa Aulia |
| Date Deposited: | 25 Jul 2025 04:01 |
| Last Modified: | 25 Jul 2025 04:01 |
| URI: | http://repository.its.ac.id/id/eprint/121491 |
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