scholarly journals Using Multi-Mission Satellite Elevation Data for Delineation of Gilgit Watershed in Pakistan in Geographical Information Technology Environment

2020 ◽  
Vol 11 (2) ◽  
pp. 19-24
Author(s):  
Muhammad Shafiq ◽  
Muhammad Irfan ◽  
Mehrab Khan
Keyword(s):  
Information Technology ◽  
Watershed Management ◽  
Multiple Scales ◽  
Climatic Conditions ◽  
Geographical Information ◽  
Indus Basin ◽  
Landsat 8 ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Elevation Data

The hydro-climatological variations in Gilgit watershed of Upper Indus basin is less scientifically understood due to diverse geography, remoteness of the region and larger variations in climatic conditions. Extraction of catchments at multiple scales is an important task in undertaking the watershed management studies. Satellite remote sensing (SRS) and geographical information technology (GIT) provide a very useful method to study the watersheds. In view of the facts, watershed/ natural resources management in Gilgit river basin, application of geospatial techniques to various elevation datasets is required in order to obtain more accurate results using these elevation datasets. To achieve this goal, the topographic feature extraction has been studied in the catchment of Gilgit river using different Digital Elevation Models (DEMs) viz., SRTM, ASTER GDEM and GTOPO30. Several small watersheds for the Phakor, Karamber, East Gammu, Bhort and Bad-e-Swat glaciers were delineated for the basin definition. The delineated watersheds have been visually analyzed against the optical Landsat 8 OLI imagery for mountainous ridge matching. The results revealed that, SRTM 30m (radar based) exhibited more accuracy among these DEMs because of its precise delineation in the Gilgit sub-basin. However, it is appropriate to say that computed area from all three DEMs generally show close agreement. This study is a good contribution towards better understanding of the watershed management and the hydrological responses in Gilgit watershed of the upper Indus catchment.

scholarly journals HydroSHEDS v2.0 – Refined global river network and catchment delineations from TanDEM-X elevation data

2021 ◽  
Author(s):  
Bernhard Lehner ◽  
Achim Roth ◽  
Martin Huber ◽  
Mira Anand ◽  
Günther Grill ◽  
...  
Keyword(s):  
High Resolution ◽  
Digital Elevation Model ◽  
Multiple Scales ◽  
Environmental Conservation ◽  
The Arctic ◽  
River Networks ◽  
Northern Latitude ◽  
Digital Elevation ◽  
Elevation Data ◽  
Elevation Model

<p>Since its introduction in 2008, the HydroSHEDS database (www.hydrosheds.org) has transformed large-scale hydro-ecological research and applications worldwide by offering standardized spatial units for hydrological assessments. At its core, HydroSHEDS provides digital hydrographic information that can be applied in Geographic Information Software (GIS) or hydrological models to delineate river networks and catchment boundaries at multiple scales, from local to global. Its various data layers form the basis for applications in a wide range of disciplines including environmental, conservation, socioeconomic, human health, and sustainability studies.</p><p>Version 1 of HydroSHEDS was derived from the digital elevation model of the Shuttle Radar Topography Mission (SRTM) at a pixel resolution of 3 arc-seconds (~90 meters at the equator). It was created using customized processing and optimization algorithms and a high degree of manual quality control. Results are available at varying resolutions, ranging from 3 arc-seconds (~90 m) to 5 minutes (~10 km), and in nested sub-basin structures, making the data uniquely suitable for applications at multiple scales. A suite of related data collections and value-added information, foremost the HydroATLAS compilation of over 50 hydro-environmental attributes for every river reach and sub-basin, continuously enhance the versatility of the HydroSHEDS family of products. Yet version 1 of HydroSHEDS shows some important limitations. In particular, coverage above 60° northern latitude (i.e., largely the Arctic) is missing for the 3 arc-second product and is of low quality for coarser products because no SRTM elevation data are available for this region. Also, some areas are affected by inherent data gaps or other errors that could not be fully resolved at the time of creating version 1 of HydroSHEDS.</p><p>Today, the TanDEM-X dataset (TerraSAR-X add-on for Digital Elevation Measurement), created in partnership between the German Aerospace Agency (DLR) and Airbus, offers a new digital elevation model covering the entire global land surface including northern latitudes. In a collaborative project, this dataset is used to extract HydroSHEDS v2.0, following the same basic specifications as version 1. DLR is processing the original 12 m resolution TanDEM-X data to create a hydrologically pre-conditioned version at 3 arc-second resolution. In this step, corrections with high-resolution vegetation and settlement maps are applied to reduce distortions caused by vegetation cover and in built-up areas. Following this preprocessing, refined hydrological optimization and correction algorithms are used to derive the drainage pathways, including improved ‘stream-burning’ techniques that incorporate recent data products such as high-resolution terrestrial open water masks and improved tracing of drainage pathways as center lines in global lake and river maps. The resulting HydroSHEDS v2.0 database will provide river networks and catchment boundaries at full global coverage. Release of the data under a free license is scheduled for 2022, with regions above 60° northern latitude being completed first in 2021.</p>

scholarly journals Co-registration and bias corrections of satellite elevation data sets for quantifying glacier thickness change

2011 ◽  
Vol 5 (1) ◽  
pp. 271-290 ◽  
Author(s):  
C. Nuth ◽  
A. Kääb
Keyword(s):  
Regional Scale ◽  
Statistical Error ◽  
Data Sets ◽  
Data Set ◽  
Thickness Change ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Elevation Data ◽  
Elevation Changes

Abstract. There are an increasing number of digital elevation models (DEMs) available worldwide for deriving elevation differences over time, including vertical changes on glaciers. Most of these DEMs are heavily post-processed or merged, so that physical error modelling becomes difficult and statistical error modelling is required instead. We propose a three-step methodological framework for assessing and correcting DEMs to quantify glacier elevation changes: (i) remove DEM shifts, (ii) check for elevation-dependent biases, and (iii) check for higher-order, sensor-specific biases. A simple, analytic and robust method to co-register elevation data is presented in regions where stable terrain is either plentiful (case study New Zealand) or limited (case study Svalbard). The method is demonstrated using the three global elevation data sets available to date, SRTM, ICESat and the ASTER GDEM, and with automatically generated DEMs from satellite stereo instruments of ASTER and SPOT5-HRS. After 3-D co-registration, significant biases related to elevation were found in some of the stereoscopic DEMs. Biases related to the satellite acquisition geometry (along/cross track) were detected at two frequencies in the automatically generated ASTER DEMs. The higher frequency bias seems to be related to satellite jitter, most apparent in the back-looking pass of the satellite. The origins of the more significant lower frequency bias is uncertain. ICESat-derived elevations are found to be the most consistent globally available elevation data set available so far. Before performing regional-scale glacier elevation change studies or mosaicking DEMs from multiple individual tiles (e.g. ASTER GDEM), we recommend to co-register all elevation data to ICESat as a global vertical reference system.

scholarly journals Mapping of Landslide Susceptible Zones by Using Frequency Ratios at Bluncong Subwatershed, Bondowoso Regency

UKaRsT ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 126
Author(s):  
Didik Efendi ◽  
Entin Hidayah ◽  
Akhmad Hasanuddin
Keyword(s):  
Landslide Susceptibility ◽  
Frequency Ratio ◽  
Local Governments ◽  
Vegetation Index ◽  
Data Interpretation ◽  
Geographical Information ◽  
Landsat 8 ◽  
Digital Elevation ◽  
Elevation Model ◽  
Frequency Ratios

Landslides are the disasters that frequently happen in Bluncong sub-watershed. These incidents have caused damage and malfunction of road infrastructure, bridges, and irrigation buildings. Therefore, it is important to anticipate landslides through mapping of landslide-susceptibility areas The objective of this study is to map landslide susceptibility at Bluncong sub watershed, Bondowoso, by using Geographical Information System and remote sensing. The landslide susceptibility analysis and mapping are conducted based on landslide occurrences with the Frequency Ratio approach. The landslide sites are identified from field survey data interpretation. Digital Elevation Model maps, geological data, land uses and rivers data, and Landsat 8 images are collected, processed, and then built into the GIS platform's spatial database. The selected factors that cause landslide occurrences are land use, distance to river, aspect, slope, elevation, curvature, and the vegetation index (NDVI). The results show that the accuracy of the map is acceptable. The frequency ratio model gained the area under curve (AUC) value of 0.79. It is found that 9.08% of the area has very high landslide susceptibility. Local governments can use this study's mapping results to minimize the risk at landslidesusceptible zones

scholarly journals An Analysis of the Flood-Prone Areas in Birnin Kebbi, Using Remote Sensing and GIS

2020 ◽  
pp. 77-85
Author(s):  
Abdullahi Muktar ◽  
Sadiq A. Yelwa
Keyword(s):  
Local Government ◽  
Shuttle Radar Topography Mission ◽  
Local Government Area ◽  
Geographical Information ◽  
Lower Altitude ◽  
Digital Elevation ◽  
Elevation Data ◽  
Point Data ◽  
Elevation Model ◽  
Flooding Events

Aim: To identify settlements that are vulnerable to flooding within River Rima floodplain in Birnin Kebbi Local Government Area of Kebbi State, Nigeria. Study Design: A flood vulnerability test was conducted by observing the relationship between the locations of settlements on the floodplain and elevation data, considering previous flooding events. Place and Duration of Study: The study covers Birnin Kebbi Local Government Area of Kebbi State, Nigeria. Methodology: This study uses Digital Elevation Model DEM obtained by The Shuttle Radar Topography Mission (SRTM). The Geographical Information System (GIS) technique (Map Overlay) was used where DEM was overplayed by settlement location (point data). Similarly, 3D view was used to confirm the result. Conclusion: The result shows that 12 settlements in Birnin Kebbi LGA were located at the lower altitude (<207m) with close proximity from the river channel. Therefore, the settlements and the surrounding farmlands become vulnerable to flooding. Recommendations: It was recommended that the settlements should be relocated to higher ground for safety. Local farmers should use species of rice that can survive longer time when submerged by water. The Environmental Monitoring Agencies should include detailed images showing affected areas in their publications.

scholarly journals Technical Methodology for ASTER Global Water Body Data Base

2018 ◽  
Author(s):  
Hiroyuki Fujisada ◽  
Minoru Urai ◽  
Akira Iwasaki
Keyword(s):  
Sea Ice ◽  
Water Body ◽  
Lake Area ◽  
Unique Challenge ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Elevation Data ◽  
Data Points ◽  
Data Files ◽  
Elevation Model

A waterbody detection technique is an essential part of digital elevation model (DEM) generation to delineate land-water boundaries and set flattened elevations. This paper describes the technical methodology for improving the initial tile-based waterbody data that are created during production of the ASTER GDEM, because without improvement such tile-based waterbody data are not suitable for incorporating into the new ASTER GDEM Version 3. Waterbodies are classified into three categories: sea, lake, and river. For sea-waterbodies, the effect of sea ice is removed to better delineate sea shorelines in high latitude areas, because sea ice prevents accurate delineation of sea shorelines. For lake-waterbodies, the major part of the processing is to set the unique elevation value for each lake using a mosaic image that covers the entire lake area. Rivers present a unique challenge, because their elevations gradually step down from upstream to downstream. Initially, visual inspection is required to separate rivers from lakes. A stepwise elevation assignment, with a step of one meter, is carried out by manual or automated methods, depending on the situation. The ASTER GWBD product consists of a global set of 1&ordm; latitude-by-1&ordm; longitude tiles containing water body attribute and elevation data files in geographic latitude and longitude coordinates and with one arc second posting. Each tile contains 3601-by-3601 data points. All improved waterbody elevation data are incorporated into the ASTER GDEM to reflect the improved results.

scholarly journals GIS Integration of Aster Stereo Imagery for the Support of Watershed Management

2013 ◽  
Vol 5 (2) ◽  
pp. 47-56
Keyword(s):  
Watershed Management ◽  
Spatial Data ◽  
Geographical Information Systems ◽  
Thermal Emission ◽  
Geographical Information ◽  
Drainage Pattern ◽  
Elevation Data ◽  
Stereo Imagery ◽  
Gis Methods ◽  
Terrain Elevation

In this study, ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) stereo imagery was analysed in combination with Global Positioning System (GPS) data and field observations, using Geographical Information Systems (GIS) techniques to examine the potential of satellite remote sensing to support watershed management. Terrain elevation data were derived for the region of Heraklion, Crete. The accuracy of the ASTER derived DEM (Digital Elevation Model), was better than 20 meters (planimetric) and better than 15 meters (elevation). Supervised classification techniques were applied for land cover production using ASTER multi-spectral imagery and filed observations at predefined application sites. The determination of training areas required in the supervised classification scheme was based on these observations. Finally, GIS methods were applied to estimate watershed characterization parameters for the study area offering the advantages of spatial data handling capabilities and automatic extraction of thematic information. The drainage pattern, which was derived, provided a generally representative depiction of the watershed. The output pixel spacing of 15 m of the produced DEM as well as the high spatial resolution of ASTER imagery found to be quite satisfactory for the watershed characterization of the study area, indicating the high potential of ASTER imagery to support watershed management.

scholarly journals Depth Faults Along The Regmatic Network Of The Chatkalo-Kuramin Region And Their Relationship With Seismicity

2020 ◽  
Vol 02 (12) ◽  
pp. 68-76
Author(s):  
Madinabonu Zaxritdinovna Fazliddinova ◽  
◽  
Akram Bayramovich Goipov ◽  
Maftuna Asad qizi Saidova ◽  
◽  
...  
Keyword(s):  
Remote Sensing ◽  
Satellite Images ◽  
Remote Sensing Data ◽  
Comprehensive Analysis ◽  
Landsat 8 ◽  
Strong Earthquakes ◽  
Sensing Data ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Lineament Analysis

Lineaments were identified using LANDSAT-8 satellite images and digital elevation models obtained from the ASTER GDEM satellite over the Chatkal-Kuramin region. Taking into account the stock materials and a comprehensive analysis of the results of processing remote sensing data, a map of lineaments of a 1: 100,000 regmatic network was compiled. Based on the automated visual lineament analysis in the Geomatica PCI program, lineaments of the regmatic network were obtained, which are located in the focal zones of strong earthquakes.

Landscape Change in the Steppe of Algeria South-West Using Remote Sensing

2018 ◽  
Vol 18 (1) ◽  
pp. 41-52
Author(s):  
Tayeb Sitayeb ◽  
Ishak Belabbes
Keyword(s):  
Remote Sensing ◽  
Social Systems ◽  
Bare Soil ◽  
Climatic Conditions ◽  
Landscape Dynamics ◽  
Landsat 8 ◽  
Natural Ecosystems ◽  
Stipa Tenacissima ◽  
Steppe Species ◽  
Sparse Vegetation

Abstract Landscape dynamics is the result of interactions between social systems and the environment, these systems evolving significantly over time. climatic conditions and biophysical phenomena are the main factors of landscape dynamics. Also, currently man is responsible for most changes affecting natural ecosystems. The objective of this work is to study the dynamics of a typical landscape of western Algeria in time and space, and to map the distribution of vegetation groups constitute the vegetation cover of this ecosystem. as well as using a method of monitoring the state of a fragile ecosystem by remote sensing to understand the processes of changes in this area. The steppe constitutes a large arid area, with little relief, covered with low and sparse vegetation. it lies between the annual isohyets of 100 to 400 mm, subjected to a very old human exploitation with an activity of extensive breeding of sheep, goats, and camels. Landsat satellite data were used to mapping vegetation groups in the Mecheria Steppe at a scale of 1: 300,000. Then, a comparison was made between the two maps obtained by a classification of Landsat-8 sensor Operational Land Imager (OLI) acquired on March 18, 2014, and Landsat-5 sensor Thematic Mapper (TM) acquired on April 25, 1987. The results obtained show the main changes affecting the natural distribution of steppe species, a strong change in land occupied by the Stipa tenacissima steppe with 65% of change, this steppe is replaced by Thymelaea microphylla, Salsola vermiculata, lygeum spartum and Peganum harmala steppe. an absence from the steppe Artemisia herba-alba that has also been replaced by the same previous steppes species. The groups with Quercus ilex and Juniperus phoenicea are characterized by a strong regression that was lost 60% of its global surface and transformed by steppe to stipa tenacissima and bare soil.

Urban Flood Mapping

2017 ◽  
Author(s):  
Indra Riyanto ◽  
Lestari Margatama
Keyword(s):  
Natural Disasters ◽  
Satisfying Condition ◽  
Three Dimensions ◽  
Urban Flood ◽  
Digital Elevation ◽  
Elevation Data ◽  
Recent Occurrence ◽  
Elevation Model ◽  
Digital Elevation Model Data ◽  
Potential Area

The recent degradation of environment quality becomes the prime cause of the recent occurrence of natural disasters. It also contributes in the increase of the area that is prone to natural disasters. Flood history data in Jakarta shows that flood occurred mainly during rainy season around January – February each year, but the flood area varies each year. This research is intended to map the flood potential area in DKI Jakarta by segmenting the Digital Elevation Model data. The data used in this research is contour data obtained from DPP–DKI with the resolution of 1 m. The data processing involved in this research is extracting the surface elevation data from the DEM, overlaying the river map of Jakarta with the elevation data. Subsequently, the data is then segmented using watershed segmentation method. The concept of watersheds is based on visualizing an image in three dimensions: two spatial coordinates versus gray levels, in which there are two specific points; that are points belonging to a regional minimum and points at which a drop of water, if placed at the location of any of those points, would fall with certainty to a single minimum. For a particular regional minimum, the set of points satisfying the latter condition is called the catchments basin or watershed of that minimum, while the points satisfying condition form more than one minima are termed divide lines or watershed lines. The objective of this segmentation is to find the watershed lines of the DEM image. The expected result of the research is the flood potential area information, especially along the Ciliwung river in DKI Jakarta.

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