KAJIAN AKURASI PETA ORTOFOTO DARI DATA WAHANA UDARA TANPA AWAK (WUTA)

RIVAN ARIEF, Dr. Diyono, S.T., M.T.

2018 | Skripsi | S1 TEKNIK GEODESI

Metode fotogrametri menggunakan Wahana Udara Tanpa Awak (WUTA) sudah menjadi alternatif dalam rangka penyedia informasi geospasial. Dalam pelaksanaannya fotogrametri menggunakan WUTA dilengkapi dengan kamera non metrik atau Foto Udara Format Kecil (FUFK) guna mereduksi biaya kegiatan pemetaan. Kamera non metrik pada awalnya tidak didesain untuk kegiatan pemetaan, sehingga kegiatan pemetaan dengan metode fotogrametri menggunakan WUTA perlu dilakukan kajian akurasi horisontal dan vertikal. Kajian akurasi ini dilakukan dengan mengacu pada ketelitian geometri peta Rupa Bumi Indonesia (RBI). Kegiatan pemetaan metode fotogrametri menggunakan WUTA dilakukan di Desa Segoroyoso, Bantul, Daerah Istimewa Yogyakarta. Kegiatan pemetaan meliputi pemotretan udara menggunakan WUTA, pengukuran Ground Control Point (GCP) sebanyak 10 titik, pengukuran Independent Control Point (ICP) sebanyak 8 titik, dan pengukuran titik uji berupa titik objek (post mark) sebanyak 7 titik. Pengukuran GCP dan ICP dilakukan dengan pengukuran GPS metode radial, sedangkan pengukuran titik uji berupa objek dilakukan dengan metode GPS RTK. Foto udara kemudian diolah secaara otomatis dengan metode structure from motion (SfM) menggunakan perangkat lunak Agisoft Photoscan. Hasil pengolahan foto udara akan menghasilkan ortofoto dan DTM. Untuk mengetahui akurasi horisontal dan vertikal, kemudian hasil pengolahan foto udara dibandingkan nilai koordinatnya dengan nilai koordinat ICP sebanyak 8 buah dan titik uji post mark sebanyak 7 buah. Berdasarkan perbandingan nilai koordinat titik uji (ICP dan post mark) dengan hasil pengolahan foto udara didapatkan RMSE horisontal sebesar 0,0777 m dan RMSE vertikal sebesar 0,5867 m. Nilai RMSE digunakan untuk menentukan nilai Circural Error 90 (CE90) dan Linear Error (LE90). Nilai didapatkan CE90 sebesar 0,1179 m dan nilai LE90 sebesar 0,96502 m. Ketelitian peta ortofoto yang dapat dibuat adalah 1:1000 pada kelas 1 untuk ketelitian horisontal dan 1:5000 pada kelas 1 untuk ketelitian vertikal.

Photogrammetry method using Unmanned Aerial Vehicle has become an alternative in order to provide geospatial information. In the implementation, photogrammetry using Unmanned Aerial Vehicle equipped with non metric camera or Small Format Aerial Photography (SFAP) in order to reduce the cost of mapping activities. Non metric camera were not originally designed for mapping activities. Thus, mapping activities with photogrammetry method using Unmanned Aerial Vehicle required the horizontal and vertical accuracy study. The accuracy study was conducted based on the Regulation of Chief BIG No. 15 of 2014. Mapping activities with photogrammetry method using unmanned aerial vehicle was conducted in Segoroyoso Village, Bantul, Special Region of Yogyakarta. Mapping activities included aerial photography using unmanned aerial vehicle, 10 points of Ground Control Points (GCP) measurement, 8 points of Independent Control Point (ICP) measurement and 7 points of check point (post mark) measurement. The measurement of GCP and ICP was conducted with GPS radial method, while the measurement of check point in the form of object was conducted with GPS RTK method. Aerial photo will be processed automatically with Structure from Motion method using Agisoft Photoscan software. The result of aerial photo processing is orthophoto and DTM. In order to assess the horizontal and vertical accuracy, the result of aerial photo processing will be compared its coordinate with the coordinate value of ICP as much as 8 points and test point of post mark as much as 7 points. The comparison of test point coordinate value (ICP and post mark) with the result of aerial photo processing obtained RMSE of horizontal with the value 0.0777 m and RMSE of vertical with the value 0.5867 m. The value of RMSE will be used to determine the value of Circural Error 90 (CE90) and Linear Error (LE90). Thus, CE90 with the value 0.1179 m and LE90 with the value 0.96502 m were obtained. Based on the Regulation of Chief BIG No. 15 of 2014, the accuracy of orthophoto map that can be used is 1:1000 in grade 1 for horizontal accuracy and 1:5000 in grade 1 for vertical accuracy.

Kata Kunci : Wahana Udara Tanpa Awak, Foto Udara Format Kecil, Ortofoto./Unmanned Aerial Vehicle, Small Format Aerial Photography, Orthophoto.