Penggunaan Citra Srtm1 dan Aster Gdem V2 untuk Pemetaan Tinggi Tegakan di Bagian Kesatuan Pemangkuan Hutan Lawu Utara

Hutan merupakan salah satu elemen penting dalam ekosistem, sehingga pengelolaannya perlu direncanakan dengan baik. Salah satu hal dalam kegiatan perencanaan tersebut adalah mengestimasi tinggi tegakan hutan. Penelitian ini dilakukan dengan tujuan untuk mengetahui kemampuan citra SRTM1 dan ASTER GDEM v2 dalam menghasilkan data tinggi tegakan hutan, serta mengetahui sebaran tinggi tegakan hutan di Bagian Kesatuan Pemangkuan Hutan Lawu Utara. Data Digital Elevation Model dan data Digital Surface Model digunakan sebagai data utama dalam menurunkan informasi tinggi tegakan. Hal ini dapat diturunkan melalui selisih nilai z.Hasil estimasi tinggi tegakan menggunakan SRTM1 menghasilkan RMSE 9,89 m, sedangkan ASTER GDEM v2 menghasilkan RMSE 10,66 m. Estimasi tinggi tegakan hutan menggunakan SRTM1 dan ASTER GDEM v2 cenderung underestimate berdasarkan perbandingan dengan data hasil pengukuran lapangan. Berdasarkan histogram maka modus pada masing-masing data DSM adalah 1,1 m pada SRTM1, dan 12,2 m pada ASTER GDEM v2. Hasil yang demikian menunjukkan bahwa kedua data DSM kurang sesuai untuk pemetaan tinggi tegakan. Namun demikian apabila akan dibuat peta maka skala peta yang sesuai untuk setiap data DSM skala 1:100.000

Evaluation of TanDEM-X DEMs on selected Brazilian sites: comparison with SRTM, ASTER GDEM and ALOS AW3D30

A first assessment of the TanDEM-X DEMs over Brazilian territory is presented through a comparison with SRTM, ASTER GDEM and ALOS AW3D30 DEMs in seven study areas with distinct geomorphological contexts, vegetation coverage and land use. Visual analysis and elevation histograms point to a finer effective spatial resolution of TanDEM-X compared to SRTM and ASTER GDEM. In areas of open vegetation, TanDEM-X lower elevations indicate a better penetration of the radar signal. DEMs of differences (DoDs) allowed the identification of issues inherent to the production methods of the analyzed DEMs, such as mast oscillations in SRTM data and mismatch between adjacent scenes in ASTER GDEM and ALOS AW3D30. A systematic difference in elevations between TanDEM-X 12m, TanDEM-X 30m and SRTM was observed in the steep slopes of the coastal ranges, related to the moving-window process used to resample the 12m data to a 30m pixel size. Due its simplicity, it is strongly recommended to produce a DoD with SRTM before using ASTER GDEM or ALOS AW3D30 in any analysis, to evaluate if the area of interest is affected by these problems. The DoDs also highlighted changes in land use in the time span between the acquisition of SRTM (2000) and TanDEM-X (2013) data, whether by natural causes or by human interference in the environment.Comment: 19 pages, 9 figures, supplementary material at GitHu

Evaluation of Morphometric Parameters Derived from CartoDEM and Aster GDEM with SOI Toposheets of Kumudvathi Watershed Basin, Karnataka, India

From three different sources viz. survey of India topographic map (1:50,000), CartoDEM (10mts) and Aster GDEM (30 mts) morphometric parameters are derived and evaluated. Manually digitized the drainage network from toposheets and extracted drainage network system from CartoDEM and Aster GDEM using ArcGIS 10.2 software. Basic, derived and shape parameters are considered for basin analysis. The mean bifurcation ratio of the given basin for CartoDEM & Aster GDEM are having nearby values and also indicates some sort of geological control, high stream frequency (Fs) is indicative of high relief and low infiltration capacity of the bedrock pointing towards the increase in stream population with respect to increase in drainage density, low drainage density (Dd) leads to coarse drainage texture, value of Lg for topographic, CartoDEM and Aster GDEM data indicating very fine texture & fine texture respectively. From the shape parameters the Kumudvathi watershed indicates it is sub-circular and elongated. The results from the high resolution data will have the nearby values and less of % variation, whereas in low resolution data % of variation is more and will not meet criteria

Efficient numerical schemes for viscoplastic avalanches. Part 2: the 2D case

This paper deals with the numerical resolution of a shallow water viscoplastic flow model. Viscoplastic materials are characterized by the existence of a yield stress: below a certain critical threshold in the imposed stress, there is no deformation and the material behaves like a rigid solid, but when that yield value is exceeded, the material flows like a fluid. In the context of avalanches, it means that after going down a slope, the material can stop and its free surface has a non-trivial shape, as opposed to the case of water (Newtonian fluid). The model involves variational inequalities associated with the yield threshold: finite volume schemes are used together with duality methods (namely Augmented Lagrangian and Bermúdez–Moreno) to discretize the problem. To be able to accurately simulate the stopping behavior of the avalanche, new schemes need to be designed, involving the classical notion of well-balancing. In the present context, it needs to be extended to take into account the viscoplastic nature of the material as well as general bottoms with wet/dry fronts which are encountered in geophysical geometries. Here we derive such schemes in 2D as the follow up of the companion paper treating the 1D case. Numerical tests include in particular a generalized 2D benchmark for Bingham codes (the Bingham–Couette flow with two non-zero boundary conditions on the velocity) and a simulation of the avalanche path of Taconnaz in Chamonix—Mont-Blanc to show the usability of these schemes on real topographies from digital elevation models (DEM)

Pengaplikasian Penginderaan Jauh Dan Sig Untuk Pemantauan Aliran Permukaan Dalam Pengendalian Pendangkalan Waduk Jatibarang

Reservoir is made because the rivers in Indonesia have too much water during the rainy season and the river debit is less water in the dry season. As the water reservoir, the Jatibarang Reservoir has a limited water capacity while the capacity can change because of the silting reservoir caused by natural and anthropogenic activity. One of the causes of the silting reservoir due to surface runoff carrying sediment from several catchment area in a degraded watershed (DAS). This research was done through the monitoring of surface runoff from data utilization of ASTER GDEM version-2 and Landsat-8. The monitoring is done periodically for the landcover in the catchment area of Jatibarang Reservoir as a main factor of controlling the degradation using the method of supervised classification and NDVI algorithms. Results of this minithesis are about the pattern of formed surface runoff and condition catchment areas which refer to the permanent landcover/ forest along with four density classes of the forest, those are non-dense, heavy, very heavy and extraordinary heavy. Based on the analysis, formed surface runoff pattern is radial because flowdirection to all directions of mountain top and creating various angles. The next analysis shows that there are 14 catchment areas in critical condition and 2 catchment areas in good condition, those are catchment area on Kreo 08 and 15. Both of catchments are identified to be good condition because their percentage of forest are more than 30%. On the other hand, forest density analysis shows that Jatibarang Reservoir's catchment areas have a relatively dense forest area of 1001.618 hectares of the total forest area of 1041,712 hectares so a relatively dense forest (with a spectral value > = 0,6) so the existing forest has been well in Jatibarang Reservoir siltation control

Comparison Workshop on a European Digital Elevation Model

This document is the report of the Comparison Workshop on a European Digital Elevation Model Co-organised by the GMES Bureau (EC, DG Enterprise and Industry) and the Institute for Environment and Sustainability (EC, DG Joint Research Centre), Stresa, Italy 5-6 May 2009JRC.H.6 - Spatial data infrastructure

Analisis Sebaran Kawasan Potensial Panas Bumi Gunung Salak Dengan Suhu Permukaan, Indeks Vegetasi Dan Geomorfologi

Indonesia is located on the intersection of three tectonic plates which contributes to the availability of geothermal energy. Studying characteristics of geothermal potential areas is the first step in the geothermal exploration. Studying the characteristics of geothermal potential conducted at Mount Salak, Sukabumi, West Java. The study was conducted using LANDSAT 8 and GDEM Aster. GDEM Aster used to analyze lineament and geomorphology. The Pattern of lineaments structure is caused by the shadow effect of sunlight that cause the dark effect on geomorphology such as mountain, and cliff. The area has a lot of lineament is weak zone. So, The weak zone could be the way out water flow onto the surface. The water flow out is Colled geothermal manifestations. In this study, lineament was found in the morphology of volcanic cones. LANDSAT 8 used to analyze of surface temperature distribution (thermal channel) and vegetation index. The Vegetation Index used NDVI method (infrared wavelength channel). The results of surface temperature indicated that the lowest temperature is in range of class 1, which is 60C to 110C, and the highest temperature is in the range of class 6, which is >350C. While the results of vegetation index indicated that the lowest value is in the range of class 1, which is 0.09 to 0.22, and the highest value is in class 4, which is > 0.48. The Statistical analysis conducted using the linear regression method. This method conducted to determine the relationship between surface temperature and NDVI. The results of linear regression indicated the infulence of surface temperature and NDVI. The influence of both is showed by the determination coefficient (R2) of 0.529 or 52.9%. So, the correlation value of -0.727 indicated strong correlation. The negative sign (-) of correlation value showed the opposite direction relationship between the two variables (surface temperature and vegetation index)

A GIS-based assessment of the Byzantine water supply system of Constantinople

Despite the extensive archaeological surveys carried out in the last decades, little attention has been paid to one of the longest water supply systems of ancient times - the Byzantine water infrastructure which fed Constantinople from the mid-late fourth century AD. This work uses modern satellite terrain data and Global Positioning System (GPS) data to assess this system and provide an improved description of its route, total length and gradient profile. 44 validated GPS Control Points were correlated with ASTER GDEM V2 digital satellite data and archaeological information in a Geographic Information System (GIS) environment. We concluded that the total length of the water supply system was 426 km, and possibly even 565 km if the fifth-century aqueduct continued in parallel all the way to Constantinople rather than merging with the fourth-century aqueduct. The gradient of the channels varied across their length, being steepest near the spring sources, with gradient mostly in the region of 5 m/km, and flattest at around 0.4 m/km in the most downstream section nearest the City. This reconstruction of the gradient profile provides valuable insight into the physical characteristics of the system, allowing future study of its hydraulic function

PENGGUNAAN CITRA SRTM1 DAN ASTER GDEM V2 UNTUK PEMETAAN TINGGI TEGAKAN DI BAGIAN KESATUAN PEMANGKUAN HUTAN LAWU UTARA

Hutan merupakan salah satu elemen penting dalam ekosistem, sehingga pengelolaannya perlu direncanakan dengan baik. Salah satu hal dalam kegiatan perencanaan tersebut adalah mengestimasi tinggi tegakan hutan. Penelitian ini dilakukan dengan tujuan untuk mengetahui kemampuan citra SRTM1 dan ASTER GDEM v2 dalam menghasilkan data tinggi tegakan hutan, serta mengetahui sebaran tinggi tegakan hutan di Bagian Kesatuan Pemangkuan Hutan Lawu Utara. Data Digital Elevation Model dan data Digital Surface Model digunakan sebagai data utama dalam menurunkan informasi tinggi tegakan. Hal ini dapat diturunkan melalui selisih nilai z.Hasil estimasi tinggi tegakan menggunakan SRTM1 menghasilkan RMSE 9,89 m, sedangkan ASTER GDEM v2 menghasilkan RMSE 10,66 m. Estimasi tinggi tegakan hutan menggunakan SRTM1 dan ASTER GDEM v2 cenderung underestimate berdasarkan perbandingan dengan data hasil pengukuran lapangan. Berdasarkan histogram maka modus pada masing-masing data DSM adalah 1,1 m pada SRTM1, dan 12,2 m pada ASTER GDEM v2. Hasil yang demikian menunjukkan bahwa kedua data DSM kurang sesuai untuk pemetaan tinggi tegakan. Namun demikian apabila akan dibuat peta maka skala peta yang sesuai untuk setiap data DSM skala 1:100.000