Digital Elevation Modeling of Inaccessible Slope by Using Close-range Photogrammetric Data

Digital Elevation Model (DEM) currently is extensively used extensively in various applications such as for natural hazard assessment and monitoring of high risk areas. DEM data source of inaccessible areas can be collected by using several methods, but mostly are costly and requires sophisticated instruments. Due to these conditions, close-range photogrammetry offers a low cost alternative solution. Materials presented in this thesis are based on the experiments to explain the application of close-range photogrammetry with the aid of commercial digital pocket camera as DEM data collection tools, applied on inaccessible slope areas. The analysis covers calibration of the camera and surveying instruments, DEM data collections, data processing and visualization, together with DEM quality measures. The data collections are accomplished on several study areas with different topographical characteristics by using close-range photogrammetry technique. The sampling points were selected on stereo model, by using three types of sampling methods. The DEM quality measures are assessed by following elevation interpolation error and volumetric difference error analyses. The representation of the DEM is generated using TIN-based (Triangular Irregular Network) approach. The result shows that the method is able to be applied for three dimensional (3D) modeling of potentially unstable slope areas, with accuracy of less than 15 cm in RMS for elevation error and is less than 1% in volume error. The result has indicated that topographical condition has not affected the accuracy of generated DEM. Improvement of point density radically enhances the DEM’s quality, up to a certain level of point density beyond which the increment of the accuracy is not significant. The difference setting of focal length has also influences the quality of captured images, and drastically affects the accuracy of the DEM. If the accuracy of the DEM is a matter of concern, the preferred sampling method is selective sampling, while if accuracy and DEM’s time generation are the concern the most effective sampling method is regular sampling method. Since there was no permanent points on the observed slope surface, velocity and direction of landslide could not be accurately determined. However the distribution of massmovement and elevation changed on the slope surfaces can be modeled through spatialcalculation of overlaying DEMs together with profiling of cross-section and longitudinalsection of the generated DEMs

Digital Elevation Modeling oflnaccessible Slope by Using Close-range Photogrammetric Data

Digital Elevation Model (DEM) currently is extensively used extensively in vanous applications such as for natural hazard assessment and monitoring of high risk areas. DEM data source of inaccessible areas can be collected by using several methods, but mostly are costly and requires sophisticated instruments. Due to these conditions, close-range photograrnmetry offers a low cost alternative solution. Materials presented in this thesis are based on the experiments to explain the application of close-range photogrammetry with the aid of commercial digital pocket camera as DEM data collection tools, applied on inaccessible slope areas. The analysis covers calibration of the camera and surveying instruments, DEM data collections, data processing and visualization, together with DEM quality measures. The data collections are accomplished on several study areas with different topographical characteristics by using close-range photograrnmetry technique. The sampling points were selected on stereo model, by using three types of sampling methods. The DEM quality measures are assessed by following elevation interpolation error and volumetric difference error analyses. The representation of the DEM is generated using TIN-based (Triangular Irregular Network) approach. The result shows that the method is able to be applied for three dimensional (3D) modeling of potentially unstable slope areas, with accuracy of less than 15 em in RMS for elevation error and is less than 1% in volume error. The result has indicated that topographical condition has not affected the accuracy of generated DEM. Improvement of point density radically enhances the DEM's quality, up to a certain level of point density beyond which the increment of the accuracy is not significant. The difference setting of focal length has also influences the quality of captured images, and drastically affects the accuracy of the DEM. If the accuracy of the DEM is a matter of concern, the preferred sampling method is selective sampling, while if accuracy and DEM's time generation are the concern the most effective sampling method is regular sampling method. Since there was no permanent points on the observed slope surface, velocity and direction of landslide could not be accurately determined. However the distribution of massmovement and elevation changed on the slope surfaces can be modeled through spatialcalculation of overlaying DEMs together with profiling of cross-section and longitudinalsection of the generated DEMs

Digital Elevation Modeling of Inaccessible Slope by Using Close-range Photogrammetric Data

Digital Elevation Model (DEM) currently is extensively used extensively in various applications such as for natural hazard assessment and monitoring of high risk areas. DEM data source of inaccessible areas can be collected by using several methods, but mostly are costly and requires sophisticated instruments. Due to these conditions, close-range photogrammetry offers a low cost alternative solution. Materials presented in this thesis are based on the experiments to explain the application of close-range photogrammetry with the aid of commercial digital pocket camera as DEM data collection tools, applied on inaccessible slope areas. The analysis covers calibration of the camera and surveying instruments, DEM data collections, data processing and visualization, together with DEM quality measures. The data collections are accomplished on several study areas with different topographical characteristics by using close-range photogrammetry technique. The sampling points were selected on stereo model, by using three types of sampling methods. The DEM quality measures are assessed by following elevation interpolation error and volumetric difference error analyses. The representation of the DEM is generated using TIN-based (Triangular Irregular Network) approach. The result shows that the method is able to be applied for three dimensional (3D) modeling of potentially unstable slope areas, with accuracy of less than 15 cm in RMS for elevation error and is less than 1% in volume error. The result has indicated that topographical condition has not affected the accuracy of generated DEM. Improvement of point density radically enhances the DEM’s quality, up to a certain level of point density beyond which the increment of the accuracy is not significant. The difference setting of focal length has also influences the quality of captured images, and drastically affects the accuracy of the DEM. If the accuracy of the DEM is a matter of concern, the preferred sampling method is selective sampling, while if accuracy and DEM’s time generation are the concern the most effective sampling method is regular sampling method. Since there was no permanent points on the observed slope surface, velocity and direction of landslide could not be accurately determined. However the distribution of massmovement and elevation changed on the slope surfaces can be modeled through spatialcalculation of overlaying DEMs together with profiling of cross-section and longitudinalsection of the generated DEMs

Digital Elevation Modeling oflnaccessible Slope by Using Close-range Photogrammetric Data

Digital Elevation Model (DEM) currently is extensively used extensively in vanous applications such as for natural hazard assessment and monitoring of high risk areas. DEM data source of inaccessible areas can be collected by using several methods, but mostly are costly and requires sophisticated instruments. Due to these conditions, close-range photograrnmetry offers a low cost alternative solution. Materials presented in this thesis are based on the experiments to explain the application of close-range photogrammetry with the aid of commercial digital pocket camera as DEM data collection tools, applied on inaccessible slope areas. The analysis covers calibration of the camera and surveying instruments, DEM data collections, data processing and visualization, together with DEM quality measures. The data collections are accomplished on several study areas with different topographical characteristics by using close-range photograrnmetry technique. The sampling points were selected on stereo model, by using three types of sampling methods. The DEM quality measures are assessed by following elevation interpolation error and volumetric difference error analyses. The representation of the DEM is generated using TIN-based (Triangular Irregular Network) approach. The result shows that the method is able to be applied for three dimensional (3D) modeling of potentially unstable slope areas, with accuracy of less than 15 em in RMS for elevation error and is less than 1% in volume error. The result has indicated that topographical condition has not affected the accuracy of generated DEM. Improvement of point density radically enhances the DEM's quality, up to a certain level of point density beyond which the increment of the accuracy is not significant. The difference setting of focal length has also influences the quality of captured images, and drastically affects the accuracy of the DEM. If the accuracy of the DEM is a matter of concern, the preferred sampling method is selective sampling, while if accuracy and DEM's time generation are the concern the most effective sampling method is regular sampling method. Since there was no permanent points on the observed slope surface, velocity and direction of landslide could not be accurately determined. However the distribution of massmovement and elevation changed on the slope surfaces can be modeled through spatialcalculation of overlaying DEMs together with profiling of cross-section and longitudinalsection of the generated DEMs

Application of spot5 satellite image and gis for updating road network: towards building landslide spatial database

Rapid development in urbanization is usually followed by development in transportation network. As the consequence, latest developed road networks are not found on the existing topographic map. As the topographic map-derived road network is not updated in short period, it is important to shorten the map updating cycles. SPOT 5 satellite image offers a cost effective way for updating the map compared to a conventional mapping method. The image, acquired in 2005, is used for updating road network on topographic map scaled at 1:50000, sheet 74, issued by JUPEM which was derived from aerial photograph taken in 1981. The road connecting Simpang Pulai cross and Kampung Raja, Cameron Highlands, is selected due to its considerably rapid development and susceptibility to landslide. Since most landslide occurrences take place along the road, updating road map as part of landslide geo-database becomes necessary. SPOT5 image is registered into Malaysian Coordinate System, RSO, to conform to the existing registered topographic map. Both image classification and on screen digitization methods are used to extract road network feature. The latest method is applied to complement to the first one in case of facing uncertainty in image classification. The quality of extracted road network from image classification is discussed. The extracted road network is stored into landslide spatial database. In regard to landslide aspects, features such as barren land, vegetation coverage, are also extracted. DEM derived from topographic map is used to generate slope risk map. GIS analysis is performed to locate high risk areas that prone to landslide based on two criteria. Those areas having high risk slope (200-350) and occupy barren/un-vegetated land are considered as high risk area. From this study, only 0.1% of areas occupy high risk locations. Some of which is located at existing slope failure area at Pos Slim

Perbandingan Beberapa Metode Interpolasi untuk Pembentukan Digital Terrain Model dari Peta Topografi Skala Besar

Digital Terrain Model (DTM) merupakan suatu model pendekatan matematis dari data posisi planimetris dan vertikal untuk menyajikan keadaan permukaan bumi. Sumber data untuk pembuatan DTM meliputi data titik tinggi dan/atau garis kontur yang dapat diperoleh dari pengukuran langsung di lapangan, konversi dari peta topografi, teknik fotogrammetri, INSAR dan LIDAR. DTM dibuat dengan menggunakan metode interpolasi tertentu. Tulisan ini, membahas perbandingan penggunaan tiga metode interpolasi yang berbeda, yaitu Inverse Distance Weighted (IDW), Spline, dan Triangular Irregular Network (TIN) untuk pembuatan DTM dengan data dari peta topografi skala besar. Peta topografi tersedia dalam skala 1:5000 yang dibuat dengan metode fotogrametri. Peta memiliki kerapatan kontur 2 meter dan ribuan titik tinggi yang tersebar di daerah studi dengan elevasi dan kelerengan yang bervariasi. Kontur dan titik tinggi digunakan untuk membuat DTM dengan tiga metode yang berbeda. Evaluasi dilakukan dengan analisis secara visual dan matematis pada daerah uji. Analisis visual dilakukan dengan mengamati adanya anomali lubang dan puncak yang terbentuk. Analisis secara matematis dilakukan dengan perhitungan RMS error beberapa titik sampel dengan tingkat kepercayaan 95%. Titik sampel diambil pada daerah datar, berbukit jarang dan berbukit rapat. Hasil akhir DTM disajikan dalam format raster untuk memudahkan proses evaluasi. Penggunaan metode TIN menghasilkan DTM dengan RMS error 1,54 meter, metode IDW menghasilkan RMS error 1,79 meter, dan 1,78 meter pada metode Spline. Evaluasi secara visual dan analisis matematis menunjukkan bahwa metode IDW baik digunakan pada daerah datar-rapat. Metode Spline baik digunakan pada daerah berbukit-rapat dan berbukit-jarang, sedangkan metode TIN baik digunakan pada daerah datar-jarang; peralihan-rapat, dan peralihan-jarang. Kata kunci: Digital Terrain Model, interpolasi, peta topografi

Pemantauan Perubahan Kedalaman dan Persebaran Sedimentasi Bendungan Berdasarkan Data Pengukuran Batimetri (Studi kasus: Waduk Sermo, Kec. Kokap Kab. Kulonprogo – DIY)

Air merupakan sebuah potensi dan sumber daya yang harus tetap diperhatikan ketersediaan dan distribusinya, diharapkan dengan pengelolaan yang baik bancana kekeringan ataupun banjir tidak akan terjadi. Salah satu usahanya adalah pembangunan bendungan yang membendung aliran sungai pada daerah tertentu. Pembuatan bendungan selalu diiringi dengan perkembangan aktifitas masyarakat sekitar, baik kegiatan wisata, ekonomi, maupun aktifitas sehari-hari. Sayangnya aktifitas ini seringnya berdampak negatif terhadap kondisi bendungan sendiri, seperti terjadinya erosi dan pendangkalan bendungan. Apabila hal ini tidak diperhatikan dengan seksama, keberadaan bendungan sebagai penyedia air bagi masyarakat pasti terancam. Paper ini mencoba menyajikan cara pemantauan sedimentasi yang terjadi beserta persebarannya, sekaligus memantau perubahan volume airnya. Dengan mengambil studi kasus di waduk sermo yang terletak di desa Hargosari, Kokap-Kulonprogo, diharapkan teknik ini bisa aplikasikan pada bendungan lainnya. Perhitungan sedimentasi serta perubahan volume air yang terjadi pada bendungan diturunkan dari data topografi dasar bendungan. Pengukuran batimetri dilakukan pada 06/08/2005 24/06/2006, menggunakan echosounder dan GPS. Hasil pemetaan berupa peta batimetri dimensi. Berdasarkan peta tersebut, dihitung luas permukaan dan volume air bendungan. Pesebaran dan kondisi sedimentasi bendungan diketahui dengan membandingkan peta batimetri 2006 dengan peta 2005. Perhitungan arus dilakukan untuk mengetahui pengaruh arus terhadap persebaran sedimentasi. Berdasarkan hasil perhitungan, diketahui bahwa dalam waktu ±1 tahun terjadi sedimentasi sebanyak 861.582,912 m3 yang tersebar pada dasar bendungan dengan luas komulatif adalah 1.331.774 m2 (tesebar di 86,62% dari permukaan dasar bendungan, dengan ketebalan rerata adalah 0,647 m). Hasil pengukuran arus menunjukkan bahwa tidak terdapat arus di dasar bendungan yang bisa memindahkan sedimentasi, yang ada hanyalah arus dipermukaan bendungan saja Kata kunci: suvei batimetri, sedimentasi, pendangkalan bendungan, perubahan volume air

Evaluasi Kemampuan Alat Fish Finder Garmin MapSounder 178C Dan EchoSounder ODOM Hydrotrac II Untuk Pengukuran Batimetri

Bathymetric mapping is needed in order to provide geo-spatial information for planning and decision making activities related to information of inland and marine waters. There are various technologies that can be used to generate the bathymetric data, one of them is by using a single beam echo sounder (SBES). There are two types of SBES , ie standard single beam echo sounder and fish finder. Fish finder is a low cost alternative depth gauges, but the resulted accuracy based on the existing specifications is lower, compared to the standard SBES. Nevertheless it is necessary to compare the bathymetric data measured using both those tools. It was performed in order to provide a comparative picture, whether the quality of the data measured by the fish finder and a standard SBES are different or not, by following the referral standardization IHO SP - 44 in 2008 and ISO 7646 in 2010. The works in this study consist of the measurement scenario design, equipments configuration, calibration barcheck, sounding (data collection), data processing , quality testing, and comparison of the depth data refers to the IHO and SNI standardizations. Based on the results of quality testing of the depth data measured by both fish finder and standard SBES, the resulted depths meet IHO and SNI standardizations for both uniform and varied depth areas. When viewed from the position of the placement of standard SBES and fish finder transducers in term of statistical test with a confidence level of 95 %, transducers placed side by side will produce different data statistically. However if the transducer placed on opposite left and right side of the ship will result in data that are not statistically different. In term of precission, transducers placed side by side produced better result than opposite positio

Pemanfaatan Prototip ROV (Remotely Operated Vehicle) dan Aplikasi Antarmuka untuk Visualisasi Jalur Perum dalam Survei Batimetri

Boat / ship has been conventionally used as a vehicle for bathymetry survey using echosounder. One of the main factors that influence the effectiveness of the implementation of bathymetry survey using a boat / ship is in the flexibility of doing the survey along and across the predefined survey lanes. In the narrow waters (small dam sluice gates, settling pond area of open pit and so on), this activities are always constrained. This study aims to build ROV prototype that can be used as an alternative vehicle for bathymetric surveys in narrow waters. ROV planned to be used in this study is a mini boat controlled using a remote control. By using a smaller vehicle it is expected that the survey will be more flexible. This study also aimed to produce an application interface that can be used by surveyors to control ROV during the survei execution along and across the predefined survey lane. The interface is planned to provide visual guidance to the operator during the survey excution. Based on the result of the work it can be concluded that the ROV can be used for bathymetric measurements with the spacing between survey lanes of below 7,5m. The time needed to make the shift between lanes is below 30 seconds. ROV still requires further development due to the slow movement during the survey. Application interfaces generated in this study is called VisualLine with 1.01Mb size and can run on Windows operating systems. This application can display the position of the ROV, survey lanes and the distance between the ROV position to the closest survey lane. In general, the application runs fine due to the the absence of rogram error during the simulations. From the simulation results, the application VisualLine can provide the required guidance on two different methods that are predefined survey lane and postdefined survey lane