Development of a flood water level estimation method using satellite images and a digital elevation model for the Mekong floodplain

2019 ◽  
Vol 64 (2) ◽  
pp. 241-253 ◽  
Author(s):  
Kenji Tanaka ◽  
Yoichi Fujihara ◽  
Keisuke Hoshikawa ◽  
Hideto Fujii
Keyword(s):  
Water Level ◽  
Digital Elevation Model ◽  
Satellite Images ◽  
Estimation Method ◽  
Flood Water ◽  
Digital Elevation ◽  
Elevation Model

scholarly journals Fusion Analysis of Optical Satellite Images and Digital Elevation Model for Quantifying Volume in Debris Flow Disaster

2019 ◽  
Vol 11 (9) ◽  
pp. 1096 ◽  
Author(s):  
Hiroyuki Miura
Keyword(s):  
Debris Flow ◽  
Digital Elevation Model ◽  
Large Scale ◽  
Satellite Images ◽  
Erosion Depth ◽  
Digital Elevation ◽  
Elevation Model ◽  
Fusion Analysis ◽  
Optical Satellite Images ◽  
Debris Flow Disaster

Rapid identification of affected areas and volumes in a large-scale debris flow disaster is important for early-stage recovery and debris management planning. This study introduces a methodology for fusion analysis of optical satellite images and digital elevation model (DEM) for simplified quantification of volumes in a debris flow event. The LiDAR data, the pre- and post-event Sentinel-2 images and the pre-event DEM in Hiroshima, Japan affected by the debris flow disaster on July 2018 are analyzed in this study. Erosion depth by the debris flows is empirically modeled from the pre- and post-event LiDAR-derived DEMs. Erosion areas are detected from the change detection of the satellite images and the DEM-based debris flow propagation analysis by providing predefined sources. The volumes and their pattern are estimated from the detected erosion areas by multiplying the empirical erosion depth. The result of the volume estimations show good agreement with the LiDAR-derived volumes.

scholarly journals New discoveries on astronomical orientation of Inca site in Ollantaytambo, Peru

2015 ◽  
Vol 14 (2) ◽  
pp. 37-46
Author(s):  
Karolína Hanzalová ◽  
Jaroslav Klokočník ◽  
Jan Kostelecký
Keyword(s):  
Digital Elevation Model ◽  
Satellite Images ◽  
Observation Point ◽  
Google Earth ◽  
The Sun ◽  
Winter Solstice ◽  
Machu Picchu ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Temple

<p>This paper deals with astronomical orientation of Incas objects in Ollantaytambo, which is located about 35 km southeast from Machu Picchu, about 40 km northwest from Cusco, and lies in the Urubamba valley. Everybody writing about Ollantaytambo, shoud read Protzen. (1)  He devoted his monograph to description and interpretation of that locality. Book of Salazar and Salazar (2) deals, among others, with the orientation of objects in Ollantaytambo with respect to the cardinal direction. Zawaski and Malville (3) documented astronomical context of major monuments of nine sites in Peru, including Ollantaytambo. We tested astronomical orientation in these places and confirm or disprove hypothesis about purpose of Incas objects. For assessment orientation of objects we used our measurements and also satellite images on Google Earth and digital elevation model from ASTER. The satellite images were used to estimate the astronomical-solar-solstice orientation, together with terrestrial images from Salazar and Salazar (2). The digital elevation model is useful in the mountains, where we need the actual horizon for a calculation of sunset and sunrise on specific days (solstices), which were for Incas people very important. We tested which astronomical phenomenon is connected with objects in Ollantaytambo. First, we focused on Temple of the Sun, also known the Wall of six monoliths.  We tested winter solstice sunrise and the rides of the Pleiades for the epochs 2000, 1500 and 1000 A.D. According with our results the Temple isn´t connected neither with winter solstice sunrise nor with the Pleiades. Then we tested also winter solstice sunset. We tried to use the line from an observation point near ruins of the Temple of Sun, to west-north, in direction to sunset. The astronomical azimuth from this point was about 5° less then we need. From this results we found, that is possible to find another observation point. By Salazar and Salazar (2) we found observation point at the corner (east rectangle) of the pyramid by <em>Pacaritanpu,</em> down by the riverside. There is a line connecting the east rectangular “platform” at the river, going along the Inca road up to vicinity of the Temple of the Sun and then in the direction to the Inca face. Using a digital elevation model we found the astronomical azimuth, which is needed for confirm astronomical orientation of the Temple. So, finally we are able to demonstrate a possibility of the solar-solstice orientation in Ollantaytambo.</p>

scholarly journals Monitoring Deformasi Gunung Merapi Menggunakan Citra Sentinel-1A Dengan Menggunakan Metode DInSAR (Studi Kasus: Gunung Merapi, Jawa Tengah)

2020 ◽  
Vol 4 (1) ◽  
pp. 14-23
Author(s):  
Rian Nurtyawan ◽  
Lady Suci Utami
Keyword(s):  
Digital Elevation Model ◽  
Volcanic Activity ◽  
Satellite Images ◽  
Disaster Mitigation ◽  
Deformation Method ◽  
Differential Interferometry ◽  
Digital Elevation ◽  
Image Pairs ◽  
Elevation Model ◽  
Deformation Map

ABSTRAKIndonesia mempunyai 127 gunung api aktif yang tersebar dari Sabang sampai Merauke. Oleh karena itu, perlu adanya pemantauan aktivitas gunung api yang dapat digunakan untuk acuan mitigasi bencana. Pada penelitian ini menggunakan metode deformasi, metode deformasi merupakan perubahan bentuk, posisi, dan dimensi dari suatu benda. Tujuan dari pemantauan deformasi ini untuk mengetahui perubahan gunung api yang disebabkan oleh aktivitas gunung api. Pemantauan aktivitas gunung api metode deformasi dilakukan dengan menggunakan citra Sentinel-1A yang diolah dengan teknologi Differential Interferometry SAR (DInSAR). Dalam penelitian ini dilakukan pengolahan dengan teknologi DInSAR metode two-pass dari empat buah citra satelit sentinel-1A 10 Januari 2018, 27 Februari 2018, 10 Mei 2018 dan 22 Januari 2019 serta data Digital Elevation Model (DEM) SRTM dengan ketelitian 30 meter .Hasil dari penelitian ini yaitu peta deformasi pra 1 erupsi yang diolah dari pasangan citra 10 Januari 2018 dengan citra 27 Februari 2018 yang menghasilkan deflasi sebesar -0,12 meter, dan peta deformasi pra 2 erupsi yang diolah dari pasangan citra 27 Februari 2018 dan 10 Mei 2018 menghasilkan deflasi sebesar -0,27 meter serta peta pasca erupsi yang diolah dari pasangan citra 10 Mei 3018 dan 22 Januari 2019 menghasilkan deflasi sebesar -0,194 meter.Kata kunci: Deformasi, Gunung Merapi, Sentinel-1A, DInSAR. ABSTRACT Indonesia has 127 active volcanoes spread over from Sabang to Merauke. Therefore, it is necessary to monitor volcanic activity that can be used as a reference for disaster mitigation. In this study, deformation method was used to reflect a change in the shape, position, and dimensions of an object. The purpose of monitoring this deformation is to find out volcanic changes caused by volcanic activity. Monitoring the volcanic activity of the deformation method is carried out using Sentinel-1A images processed with Differential Interferometry SAR (DInSAR) technology. In this research, two-pass method of DInSAR technology was processed using four sentinel-1A satellite images on January 10, 2018, February 27, 2018, May 10, 2018 and January 22, 2019 and SRTM Digital Elevation Model (DEM) data with 30 meters accuracy. This research processed pre-eruption deformation map from the 10 January 2018 imagery pair with the 27 February 2018 image which resulted in a deflation of 0.12 meters. Pre- eruption 2 deformation map was processed from the 27 February 2018 and 10 May 2018 image pairs and resulted in a deflation of 0.27 meters while post-eruption map processed from the 10 May 3018 and 22 January 2019 image pairs resulted in deflation of 0.194 meters.Keywords: Deformation, Merapi Mountain, Sentinel-1A, DinSAR.

scholarly journals A Method for Dynamical Sub-Watershed Delimitating by No-Fill Digital Elevation Model and Defined Precipitation: A Case Study of Wuhan, China

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 486
Author(s):  
Hongping Zhang ◽  
Xinwen Cheng ◽  
Lei Jin ◽  
Dong Zhao ◽  
Tianjing Feng ◽  
...  
Keyword(s):  
Water Level ◽  
Digital Elevation Model ◽  
Flood Control ◽  
Return Periods ◽  
Wuhan City ◽  
Urban Flood ◽  
Digital Elevation ◽  
Elevation Model ◽  
Control Management

Watershed delimitation is very important in flood control management. The traditional sub-watersheds delimitated by a filling digital elevation model (DEM) may change the real sink area, such that it may not be the best choice in studies sensitive to sub-watershed storage. This paper proposes a dynamical watershed delimitation method using a no-fill DEM and precipitation. It considers a closed sink area containing cells that fully flow into a large special cell, which can flow out when its water level is “higher than outlet”. We took Wuhan City as a study area and defined the precipitation in return periods of 1, 5, 20, or 100 years to derive the sub-watersheds. It is found that, in the four delimitations, the ratio of isolated basic units which could not flow outside were 27%, 9%, 5%, and 1%, respectively, as the precipitation increased. The results show that the provided method satisfies the assumption that the sink area might overflow with increased precipitation. The sub-watershed delimitated by the proposed method has higher correlation with the distribution of waterlogging points than those delimitated according to the D8 algorithm. These findings indicate that the proposed method can derive reasonable sub-watershed delimitation and that it may be helpful in the practice of urban flood control management.

scholarly journals Genangan Banjir Pasang Pada Kawasan Pemukiman di Kecamatan Sayung, Kabupaten Demak – Provinsi Jawa Tengah

2015 ◽  
Vol 18 (1) ◽  
Author(s):  
Petrus Subardjo ◽  
Raden Ario
Keyword(s):  
Water Level ◽  
Digital Elevation Model ◽  
Model Verification ◽  
Sea Surface ◽  
Tidal Inundation ◽  
Central Java ◽  
Inundation Area ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Impact

Wilayah pedesaan di Kecamatan Sayung, Kabupaten Demak merupakan daerah pemukiman yang sering terjadi banjir pasang. Banjir pasang yang menggenangi daerah tersebut karena ketinggian daratan sejajar dan atau lebih rendah dengan muka air laut. Hal ini diduga disebabkan karena terjadinya pasang surut tinggi tertinggi atau HHWL (High Highest Water Level) di wilayah tersebut, sehingga diperlukan suatu tindakan untuk menanggulangi maupun mengurangi dampak yang ditimbukan oleh hal tersebut. Tujuan penelitian ini adalah untuk mengetahui kenaikan pasang surut tinggi tertinggi dari setiap tahunnya dari data nilai HHWL tertinggi setiap bulannya dalam satu tahun. Pengolahan data menggunakan metode admiralty dari tahun 2004-2013 dan tipe pasang surut di Kecamatan Sayung, Kabupaten Demak, serta pemetaan luas area genangan dan luas kawasan pemukiman pada area genangan banjir pasang di Kecamatan Sayung, Kabupaten Demak. Metode yang digunakan dalam penelitian ini adalah metode deskriptif yang bersifat eksploratif yaitu bertujuan untuk menggambarkan keadaan atau status fenomena. Penelitian ini dapat memberikan gambaran tentang situasi dan kondisi secara lokal dan hasilnya tidak dapat digeneralisasikan untuk waktu dan tempat yang berbeda. Selain itu perlu diketahui faktor-faktor penyebab banjir pasang di wilayah tersebut. Data utama yang dibutuhkan adalah data pasang surut, Digital Elevation Model (DEM), titik verifikasi banjir pasang pada kawasan pemukiman,peta tata guna lahan Kabupaten Demak tahun 2008 dan peta rupabumi tahun 2001. Berdasarkan hasil dari penelitian ini diketahui bahwa luas genangan banjir pasang yang terjadi di Kecamatan Sayung, Kabupaten Demak pada tahun 2013 adalah 1.938, 42 ha dan luas kawasan pemukiman pada area genangan sebesar 140,05 ha.Laju kenaikan Pasang surut tinggi tertinggi (HHWL) High highest Water Level dari tahun 2004 sampai tahun 2013 adalah sebesar 13.63 dan nilai HHWL tertinggi yang digunakan untuk membuat genangan banjir pasang dalam penelitian ini adalah bulan desember tahun 2013 sebesar 235.09 cm. Sedangkan Tipe pasang surut yang ada perairan Kecamatan Sayung, Kabupaten Demak adalah campuran condong harian tunggal.Kata kunci : Genangan, Banjir, Pasang, Kawasan Pemukiman, Kecamatan Sayung, Kabupaten DemakSubdistrict Sayung, Demak is the frequent flooding in residental areas. Flood tides inunndated areas which have a height of land area equal with the sea surface or lower than the sea surface. The areas thatoften Floods are Sriwulan Village, Purwosari Village, Sidogemah Village,Tugu Village, Surodadi Village, Gemulak Village, Bedono Village and Timbul Sloko Village. This happened because high highest water level at that areas, so that the action nasneccesary to overcome or decrease the impact. The purpose of this research was to determine the highest tidalrise in every year from the highest HHWL data values of each month in a year with admiralty data processing method from 2004-2013 as well as in the sub-type tidal Sayung, Demak and inundation mapping area and extensive residental areas to tidal inundation area in the district Sayung, Demak - Central Java Province. Method used in this research is descriptive explorative method that intoonded to describle the state or status of phenomenom. This research can provide an overvieuw of situation and conditions locally and the results may not generalizable to a different time and place. Besides that we need to known the causing factors of flooding in the region the main data we need required tidal flooding data, DEM (Digital Elevation Model), verification point in the settlement area, land use maps Demak in 2008 and 2001 topographical map. Based on the result of this research that widespread inundation flooding that occured in the district Sayung Demak in 2013 is 1.938,42 ha and extensive of residental areas to the inundation area of 140.05 ha. The rate of the highest tidal rise (HHWL) from 2004 to 2013 amounted 13.63 and the highest value of HHWL used to create tidal inundation in the study was desember 2013 amounted to 235.09 cm. While type of tidal waters that exist in the district Sayung, Demak is a mixture of single-learning daily.Keywords : Inundated, Flood Tide, Settlements, Subdistrict Of Sayung, Demak Regency

scholarly journals The Changes of Runoff with DEM Resolution Variations

2020 ◽  
Vol 8 (6) ◽  
pp. 2531-2538
Keyword(s):  
Land Use ◽  
Digital Elevation Model ◽  
Field Measurement ◽  
Surface Runoff ◽  
Satellite Images ◽  
Rational Method ◽  
The Past ◽  
Digital Elevation ◽  
Elevation Model ◽  
Upstream Catchment

Currently there has been a research gap in providing sufficient and reliable data for the estimation of surface runoff from ungauged catchment in Batang Kuranji watershed, City of Padang, West Sumatera, Indonesia. The need for such data arose from the fact that land cover changes occur rapidly in the past 20 years, and flash flood and river degradation have been experienced at an alarming scale. However, due to lack of discharge data from upstream catchment, modelling catchment response to the effect of land use changes is hampered. Field measurement is difficult due to accessibility to river tributaries in the upstream catchment. Therefore, the use of digital satellite images and digital elevation model is studied with various DEM (Digital Elevation Model) resolutions for the first time in this catchment. This catchment is situated from 95 to 1858 m above sea level with an annual rainfall of 3440 mm. This watershed is classified as steep with a watershed that has a slope of more than 40% reaching 37.01% of the entire Kuranji watershed area. This study used 30 m and 8 m DEM. Secondary data were gathered from satellite images such as MODIS (MODerate resolution Imaging Spectroradiometer) Land Use. Precipitation data were gathered from three rain gauging stations in or nearby the catchment. Stream geometry data were obtained from the Provincial Office for River Management. Annual discharge and 100-year discharge are calculated using rainfall data for the past 20 years. Runoff discharge was calculated using rational method and SCS (Soil Conservation Services) method. Overall, computed discharge decreases as DEM resolution decreases with percentage varies between 0.98% to 1.76%. The biggest difference between DEM of 30 m and 8 m was shown by the Rational method. However, the difference between years is inconsistent with methods used with no significant pattern. Using the rational method, the biggest difference was by 18.73 m3/s, making up 1.76%. With SCS-CN, however, the biggest difference was 14 m3/s or 1.32% and the smallest was 0.98%. Validation with field measurement suggests that the 8-m DEM varies only 0.16% with actual discharge. Therefore, in the Kuranji catchment, the SCS method coupled with 8-m DEM was found to be accurate for the estimation of surface runoff

Research on Modeling of Scene Simulation Database for Voyage Training Simulation System

2012 ◽  
Vol 198-199 ◽  
pp. 528-532
Author(s):  
Kai Zhao ◽  
Da Bin Hu ◽  
Jian Bo Xiao
Keyword(s):  
Digital Elevation Model ◽  
Satellite Images ◽  
Simulation System ◽  
Model Data ◽  
Scene Simulation ◽  
Digital Elevation ◽  
Training Simulation ◽  
Simulation Database ◽  
Elevation Model ◽  
Digital Elevation Model Data

Scene simulation has been widely used in many fields recently as an outstanding technology. Firstly, this paper introduces the development flow and the modeling technologies of the scene database based on the characteristics of the scene simulation system. Then, the optimization technologies of modeling in constructing the scene simulation database are illuminated. In conclusion, the paper successfully established the scenedatabase of a port with the digital elevation model data and satellite images. The experiment of scene simulation has been done with Vega Prime. The results show that it solves the conflicts of models between complexity and fidelity very well. It runs smoothly and almost meets the demands of voyage training.

scholarly journals New knowledge in determining the astronomical orientation of Incas object in Ollantaytambo, Peru

2014 ◽  
Vol XL-5 ◽  
pp. 273-276 ◽  
Author(s):  
K. Hanzalová ◽  
J. Klokočník ◽  
J. Kostelecký
Keyword(s):  
Digital Elevation Model ◽  
Satellite Images ◽  
Observation Point ◽  
Google Earth ◽  
The Sun ◽  
Winter Solstice ◽  
Machu Picchu ◽  
Digital Elevation ◽  
Elevation Model ◽  
The Temple

This paper deals about astronomical orientation of Incas objects in Ollantaytambo, which is located about 35 km southeast from Machu Picchu, about 40 km northwest from Cusco, and lies in the Urubamba valley. Everybody writing about Ollantaytambo, shoud read Protzen (1993). He devoted his monograph to description and interpretation of that locality. Book of Salazar and Salazar (2005) deals, among others, with the orientation of objects in Ollantaytambo with respect to the cardinal direction. Zawaski and Malville (2007) documented astronomical context of major monuments of nine sites in Peru, including Ollantaytambo. We tested astronomical orientation in these places and confirm or disprove hypothesis about purpose of Incas objects. For assessment orientation of objects we used our measurements and also satellite images on Google Earth and digital elevation model from ASTER. The satellite images used to approximate estimation of astronomical orientation. The digital elevation model is useful in the mountains, where we need the really horizon for a calculation of sunset and sunrise on specific days (solstices), which were for Incas people very important. By Incas is very famous that they worshiped the Sun. According to him they determined when to plant and when to harvest the crop. In this paper we focused on Temple of the Sun, also known the Wall of six monoliths. We tested which astronomical phenomenon is connected with this Temple. First, we tested winter solstice sunrise and the rides of the Pleiades for the epochs 2000, 1500 and 1000 A.D. According with our results the Temple isn't connected neither with winter solstice sunrise nor with the Pleiades. Then we tested also winter solstice sunset. We tried to use the line from an observation point near ruins of the Temple of Sun, to west-north, in direction to sunset. The astronomical azimuth from this point was about 5&deg; less then we need. From this results we found, that is possible to find another observation point. By Salazar and Salazar (2005) we found observation point at the corner (east rectangle) of the pyramid by <i>Pacaritanpu</i>, down by the riverside. There is a line connecting the east rectangular "platform" at the river, going along the Inca road up to vicinity of the Temple of the Sun and then in the direction to the Inca face. Using a digital elevation model we found the astronomical azimuth, which is needed for confirm astronomical orientation of the Temple. So, finally we are able to demonstrate a possibility of the solar-solstice orientation in Ollantaytambo.

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