scholarly journals Analisis Spasial Bencana Longsor Bukit Telogolele Kabupaten Banjarnegara Menggunakan Data Foto Udara UAV

2017 ◽  
Vol 1 (1) ◽  
pp. 77
Author(s):  
Ruli Andaru ◽  
Purnama Budi Santosa

Spatial data is a very important role in emergency command and disaster management, before, during or post disasters. When a disaster occurs, the currently geospatial information is very needed: where the center of the disaster, the area affected, the volumetric of the landslide, what facilities are damaged, and determine the location of temporary shelters. This study examines and analyze the landslide in Banjarnegara 2014 before and after the landslide using Peta Rupa Bumi Indonesia (RBI) and the UAV Aerial Photos (Unmanned Aerial Vehicle). Data before the landslide obtained from RBI, while data after landslide obtained by performing aerial photography using fixed-wing UAV in December 2014 and August 2015. These aerial photos processing with photogrammetry to produce digital orthophoto and DEM (Digital Elevation Model). Orthophoto and DEM data is used to perform geospatial analysis in both 2D and 3D. 3D analysis obtained from the extraction of DEM elevation map data values appearance of the earth (RBI) and the UAV Aerial Photo. Analysis was conducted on the four components: contouring, terrain profile/cross section, slope/gradient, and volumetric (cut and fill). Readiness management of geospatial data and information is necessary to minimize losses and speed up the process of rehabilitation and reconstruction in the areas affected by the disaster. With this spatial analysis, the estimated of volume of landslides, mapping the facility affected, and the manufacture of the soil profile (high landslide, landslide affected area) can be performed quickly and accurately.

2018 ◽  
Vol 17 (2) ◽  
pp. 65-80
Author(s):  
Eva Stopková

The paper summarizes the geodetic contribution for the Slovak team within the joint Polish-Slovak archaeological mission at Tell el-Retaba in Egypt. Surveying work at archaeological excavations is usually influenced by somewhat specific subject of study and extreme conditions, especially at the missions in the developing countries. The case study describes spatial data development according to the archaeological conventions in order to document spatial relationships between the objects in excavated trenches. The long-term sustainability of surveying work at the site has been ensured by detailed metadata recording. Except the trench mapping, Digital Elevation Model has been calculated for the study area and for the north-eastern part of the site, with promising preliminary results for further detection and modelling of archaeological structures. In general, topographic mapping together with modern technologies like Photogrammetry, Satellite Imagery, and Remote Sensing provide valuable data sources for spatial and statistical modelling of the sites; and the results offer a different perspective for the archaeological research.


Author(s):  
Scott Neurauter ◽  
Sabrina Szeto ◽  
Matt Tindall ◽  
Yan Wong ◽  
Chris Wright

3D visualization is the process of displaying spatial data to simulate and model a real three dimensional space. Using 3D visualization, Geomatic professionals are enabling pipeline engineers to make better decisions by providing an increased understanding of potential costs earlier in the design process. This paper will focus on the value of visualizing Digital Elevation Model (DEM) data through the use of hillshades and imagery-draped 3D models. From free online DEM data to high resolution Light Detection and Ranging (LiDAR) derived DEM data, the increased availability allows for a broader use of 3D visualization techniques beyond 3D analysis. Of the numerous sources available, two DEM sources will be discussed in this paper, the free low resolution DEM (CDED Level 1) and the more costly but higher resolution LiDAR based DEM. Traditional methods of evaluating potential locations for route and facilities involved a significant cost for ground truthing. Through the use of 3D visualization products, multiple potential locations can be examined for suitability without the expense of field visits for every candidate site. By focusing on the selected candidate locations using a visual desktop study, the time and expense of ground truthing all of the potential sites can be reduced significantly. Exploiting the visual value of DEM permits a productive and cost efficient methodology for initial route and facility placement on hydrocarbon projects.


2020 ◽  
Vol 12 (3) ◽  
pp. 561 ◽  
Author(s):  
Bruno Adriano ◽  
Naoto Yokoya ◽  
Hiroyuki Miura ◽  
Masashi Matsuoka ◽  
Shunichi Koshimura

The rapid and accurate mapping of large-scale landslides and other mass movement disasters is crucial for prompt disaster response efforts and immediate recovery planning. As such, remote sensing information, especially from synthetic aperture radar (SAR) sensors, has significant advantages over cloud-covered optical imagery and conventional field survey campaigns. In this work, we introduced an integrated pixel-object image analysis framework for landslide recognition using SAR data. The robustness of our proposed methodology was demonstrated by mapping two different source-induced landslide events, namely, the debris flows following the torrential rainfall that fell over Hiroshima, Japan, in early July 2018 and the coseismic landslide that followed the 2018 Mw6.7 Hokkaido earthquake. For both events, only a pair of SAR images acquired before and after each disaster by the Advanced Land Observing Satellite-2 (ALOS-2) was used. Additional information, such as digital elevation model (DEM) and land cover information, was employed only to constrain the damage detected in the affected areas. We verified the accuracy of our method by comparing it with the available reference data. The detection results showed an acceptable correlation with the reference data in terms of the locations of damage. Numerical evaluations indicated that our methodology could detect landslides with an accuracy exceeding 80%. In addition, the kappa coefficients for the Hiroshima and Hokkaido events were 0.30 and 0.47, respectively.


2020 ◽  
Vol 9 (5) ◽  
pp. 334
Author(s):  
Timofey E. Samsonov

Combining misaligned spatial data from different sources complicates spatial analysis and creation of maps. Conflation is a process that solves the misalignment problem through spatial adjustment or attribute transfer between similar features in two datasets. Even though a combination of digital elevation model (DEM) and vector hydrographic lines is a common practice in spatial analysis and mapping, no method for automated conflation between these spatial data types has been developed so far. The problem of DEM and hydrography misalignment arises not only in map compilation, but also during the production of generalized datasets. There is a lack of automated solutions which can ensure that the drainage network represented in the surface of generalized DEM is spatially adjusted with independently generalized vector hydrography. We propose a new method that performs the conflation of DEM with linear hydrographic data and is embeddable into DEM generalization process. Given a set of reference hydrographic lines, our method automatically recognizes the most similar paths on DEM surface called counterpart streams. The elevation data extracted from DEM is then rubbersheeted locally using the links between counterpart streams and reference lines, and the conflated DEM is reconstructed from the rubbersheeted elevation data. The algorithm developed for extraction of counterpart streams ensures that the resulting set of lines comprises the network similar to the network of ordered reference lines. We also show how our approach can be seamlessly integrated into a TIN-based structural DEM generalization process with spatial adjustment to pre-generalized hydrographic lines as additional requirement. The combination of the GEBCO_2019 DEM and the Natural Earth 10M vector dataset is used to illustrate the effectiveness of DEM conflation both in map compilation and map generalization workflows. Resulting maps are geographically correct and are aesthetically more pleasing in comparison to a straightforward combination of misaligned DEM and hydrographic lines without conflation.


2014 ◽  
Vol 511-512 ◽  
pp. 253-258
Author(s):  
Wen Ju Du ◽  
Bing Xie ◽  
Hui Xi Xu

In this paper, two digital elevation models of debris flow in Yingxiu mountain area are generated; one is from contour lines with manual interpretation before earthquake and the other is from high resolution aerial photos using MapMatrix software. By analyzing three random points which are not in the same edge, a new formula for calculating the volume from these three points to their projection on the datum plane is derived. Then, the volumes of the two DEMs before and after earthquake can be calculated, and the volume of the total debris flow is the difference of those two.


2017 ◽  
Vol 5 (3) ◽  
pp. 493-509 ◽  
Author(s):  
Sébastien Monnier ◽  
Christophe Kinnard

Abstract. Three glacier–rock glacier transitional landforms in the central Andes of Chile are investigated over the last decades in order to highlight and question the significance of their landscape and flow dynamics. Historical (1955–2000) aerial photos and contemporary (> 2000) Geoeye satellite images were used together with common processing operations, including imagery orthorectification, digital elevation model generation, and image feature tracking. At each site, the rock glacier morphology area, thermokarst area, elevation changes, and horizontal surface displacements were mapped. The evolution of the landforms over the study period is remarkable, with rapid landscape changes, particularly an expansion of rock glacier morphology areas. Elevation changes were heterogeneous, especially in debris-covered glacier areas with large heaving or lowering up to more than ±1 m yr−1. The use of image feature tracking highlighted spatially coherent flow vector patterns over rock glacier areas and, at two of the three sites, their expansion over the studied period; debris-covered glacier areas are characterized by a lack of movement detection and/or chaotic displacement patterns reflecting thermokarst degradation; mean landform displacement speeds ranged between 0.50 and 1.10 m yr−1 and exhibited a decreasing trend over the studied period. One important highlight of this study is that, especially in persisting cold conditions, rock glaciers can develop upward at the expense of debris-covered glaciers. Two of the studied landforms initially (prior to the study period) developed from an alternation between glacial advances and rock glacier development phases. The other landform is a small debris-covered glacier having evolved into a rock glacier over the last half-century. Based on these results it is proposed that morphological and dynamical interactions between glaciers and permafrost and their resulting hybrid landscapes may enhance the resilience of the mountain cryosphere against climate change.


2010 ◽  
Vol 56 (198) ◽  
pp. 635-646 ◽  
Author(s):  
Roman J. Motyka ◽  
Mark Fahnestock ◽  
Martin Truffer

AbstractFollowing three decades of relative stability, Jakobshavn Isbræ, West Greenland, underwent dramatic thinning, retreat and speed-up starting in 1998. To assess the amount of ice loss, we analyzed 1985 aerial photos and derived a 40 m grid digital elevation model (DEM). We also obtained a 2007 40 m grid SPOT DEM covering the same region. Comparison of the two DEMs over an area of ∼4000 km2 revealed a total ice loss of 160 ± 4 km3, with 107 ± 0.2 km3 in grounded regions (0.27 mm eustatic sea-level rise) and 53 ± 4 km3 from the disintegration of the floating tongue. Comparison of the DEMs with 1997 NASA Airborne Topographic Mapper data indicates that this ice loss essentially occurred after 1997, with +0.7 ± 5.6 km3 between 1985 and 1997 and −160 ± 7 km3 between 1997 and 2007. The latter is equivalent to an average specific mass balance of −3.7 ± 0.2 m a−1 over the study area. Previously reported thickening of the main glacier during the early 1990s was accompanied by similar-magnitude thinning outside the areas of fast flow, indicating that the land-based ice continued reacting to longer-term climate forcing.


OSEANA ◽  
2018 ◽  
Vol 43 (4) ◽  
Author(s):  
Marindah Yulia Iswari ◽  
Kasih Anggraini

DEMNAS : NATIONAL DIGITAL ELEVATION MODEL FOR COASTAL APPLICATION. DEM is a digital data which contain information about elevation. In Indonesia, DEM can be generated from elevation points or contours in RBI (Rupabumi Indonesia). DEM can be performed to research of coastal application i.e. inundation or tsunami. DEM can help to analyze vulnerability or evacuation zone for coastal hazards. DEMNAS is one product of BIG (Geospatial Information Agency) which consist of elevation data from remote sensing images. DEMNAS data has not been widely used and is still being developed but DEMNAS has an advantage of spatial resolution. DEMNAS has spatial resolution 0.27 arc-second, which is bigger than the spatial resolution of global DEM.


2020 ◽  
Vol 52 (3) ◽  
pp. 402
Author(s):  
Herlan Darmawan ◽  
Bachtiar Wahyu Mutaqin ◽  
Wahyudi Wahyudi ◽  
Agung Harijoko ◽  
Haryo Edi Wibowo ◽  
...  

The flank collapse of Anak Krakatau on 22 December 2018 caused massive topography losses that generated a devastating tsunami in Sunda Strait, which then followed by eruptions that progressively changed the topography and structure of Anak Krakatau. Here, we investigated topography and structural changes due to the December 2018 flank collapse and the following eruptions by using high resolution Digital Elevation Model (DEM) before and after the events and sentinel 1A satellite image post-flank collapsed. Results show that the volumetric losses due to the 22 December 2018 flank collapsed is ~127 x 106 m3, while the following eruptions caused ~0,8 x 106 m3 losses. Structural investigation suggests two structures that may act as failure planes. The first structure is located at the western part of volcanic edifice that associated with hydrothermal alteration and the second failure is an old crater rim which delineated an actively deform volcanic cone.


2020 ◽  
Vol 4 (1) ◽  
pp. 23-27
Author(s):  
R. O. E. Ulakpa ◽  
V.U.D. Okwu ◽  
K. E. Chukwu ◽  
M. O. Eyankware

Identification and mapping of landslide is essential for landslide risk and hazard assessment. This paper gives information on the uses of landsat imagery for mapping landslide areas ranging in size from safe area to highly prone areas. Landslide mitigation largely depends on the understanding of the nature of the factors namely: slope, soil type, lineament, lineament density, elevation, rainfall and vegetation. These factors have direct bearing on the occurrence of landslide. Identification of these factors is of paramount importance in setting out appropriate and strategic landslides control measures. Images for this study was downloaded by using remote sensing with landsat 8 ETM and aerial photos using ArcGIS 10.7 and Surfer 8 software, while Digital Elevation Model (DEM) and Google EarthPro TM were used to produce slope, drainage, lineament and elevation. From the processed landsat 8 imagery, landslide susceptibility map was produced, and landslide was category into various class; low, medium and high. From the study, it was observed that Enugu and Anambra state ranges from high to medium in terms of landslide susceptibility, Imo state ranges from medium to low.


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