Comparative evaluation of horizontal accuracy of elevations of selected ground control points from ASTER and SRTM DEM with respect to CARTOSAT-1 DEM: a case study of Shahjahanpur district, Uttar Pradesh, India

2013 ◽  
Vol 28 (5) ◽  
pp. 439-452 ◽  
Author(s):  
Kishan Singh Rawat ◽  
Anil Kumar Mishra ◽  
Vinay Kumar Sehgal ◽  
Nayan Ahmed ◽  
Vinod Kumar Tripathi
Keyword(s):  
Comparative Evaluation ◽  
Uttar Pradesh ◽  
Ground Control ◽  
Control Points ◽  
Srtm Dem ◽  
Ground Control Points

scholarly journals Archival Aerial Images Georeferencing: A Geostatistically-Based Approach for Improving Orthophoto Accuracy with Minimal Number of Ground Control Points

2020 ◽  
Vol 12 (14) ◽  
pp. 2232
Author(s):  
Manuela Persia ◽  
Emanuele Barca ◽  
Roberto Greco ◽  
Maria Immacolata Marzulli ◽  
Patrizia Tartarino
Keyword(s):  
Southern Italy ◽  
Aerial Images ◽  
Ground Control ◽  
Control Points ◽  
Territorial Planning ◽  
Ground Control Points ◽  
Study Results ◽  
Open Issue ◽  
Historical Photographs

Georeferenced archival aerial images are key elements for the study of landscape evolution in the scope of territorial planning and management. The georeferencing process proceeds by applying to photographs advanced digital photogrammetric techniques integrated along with a set of ground truths termed ground control points (GCPs). At the end of that stage, the accuracy of the final orthomosaic is assessed by means of root mean square error (RMSE) computation. If the value of that index is deemed to be unsatisfactory, the process is re-run after increasing the GCP number. Unfortunately, the search for GCPs is a costly operation, even when it is visually carried out from recent digital images. Therefore, an open issue is that of achieving the desired accuracy of the orthomosaic with a minimal number of GCPs. The present paper proposes a geostatistically-based methodology that involves performing the spatialization of the GCP errors obtained from a first gross version of the georeferenced orthomosaic in order to produce an error map. Then, the placement of a small number of new GCPs within the sub-areas characterized by the highest local errors enables a finer georeferencing to be achieved. The proposed methodology was applied to 67 historical photographs taken on a geo-morphologically complex study area, located in Southern Italy, which covers a total surface of approximately 55,000 ha. The case study showed that 75 GCPs were sufficient to garner an orthomosaic with coordinate errors below the chosen threshold of 10 m. The study results were compared with similar works on georeferenced images and demonstrated better performance for achieving a final orthomosaic with the same RMSE at a lower information rate expressed in terms of nGCPs/km2.

scholarly journals Assessing the Accuracy of SRTM Dem and Aster Gdem Datasets for the Coastal Zone of Shandong Province, Eastern China

2015 ◽  
Vol 22 (s1) ◽  
pp. 15-20 ◽  
Author(s):  
Shaopeng Luana ◽  
Xiyong Hou ◽  
Yetang Wang
Keyword(s):  
Coastal Zone ◽  
Eastern China ◽  
Explanatory Power ◽  
Shandong Province ◽  
Ground Control ◽  
Line Graphs ◽  
Control Points ◽  
Srtm Dem ◽  
Aster Gdem ◽  
Ground Control Points

Abstract This study assessed the performance of recently released 3 arc second SRTM DEM version 4.1 by CSI-CGIAR and 1 arc second ASTER GDEM version 1 and version 2 by METI-NASA in comparison with ground control points from 1:50000 digital line graphs for the coastal zone of Shandong Province, Easter China. The vertical accuracy of SRTM DEM is 13.74 m root mean square error (RMSE), and GDEM version 1 reaches 24.11 m RMSE. Version 2 of ASTER GDEM shows better performance than version 1 and SRTM DEM with a RMSE of 12.12 m. A strong correlation of the magnitude of elevation error with slope and elevation is identified, with lager error magnitudes in the steeper slopes and higher elevations. Taking into account slope and elevation has the potential to considerably improve the accuracy of the SRTM DEM and GDEM version 1 products. However, this improvement for GDEM version 2 can be negligible due to their limited explanatory power for the DEM elevation errors.

scholarly journals Accuracy of Unmanned Aerial Vehicle (UAV) and SfM Photogrammetry Survey as a Function of the Number and Location of Ground Control Points Used

2018 ◽  
Vol 10 (10) ◽  
pp. 1606 ◽  
Author(s):  
Enoc Sanz-Ablanedo ◽  
Jim Chandler ◽  
José Rodríguez-Pérez ◽  
Celestino Ordóñez
Keyword(s):  
Critical Role ◽  
Bundle Adjustment ◽  
Ground Control ◽  
Control Points ◽  
Ground Sample ◽  
Ground Control Points ◽  
Check Points ◽  
Aerial Vehicle

The geometrical accuracy of georeferenced digital surface models (DTM) obtained from images captured by micro-UAVs and processed by using structure from motion (SfM) photogrammetry depends on several factors, including flight design, camera quality, camera calibration, SfM algorithms and georeferencing strategy. This paper focusses on the critical role of the number and location of ground control points (GCP) used during the georeferencing stage. A challenging case study involving an area of 1200+ ha, 100+ GCP and 2500+ photos was used. Three thousand, four hundred and sixty-five different combinations of control points were introduced in the bundle adjustment, whilst the accuracy of the model was evaluated using both control points and independent check points. The analysis demonstrates how much the accuracy improves as the number of GCP points increases, as well as the importance of an even distribution, how much the accuracy is overestimated when it is quantified only using control points rather than independent check points, and how the ground sample distance (GSD) of a project relates to the maximum accuracy that can be achieved.

scholarly journals Comparison of Digital Elevation Models for the designing water reservoirs: a case study Pskom water reservoir

2021 ◽  
Vol 264 ◽  
pp. 03058
Author(s):  
Khojiakbar Khasanov ◽  
Azamat Ahmedov
Keyword(s):  
Water Reservoir ◽  
Vertical Axis ◽  
Ground Control ◽  
Control Points ◽  
Alos Palsar ◽  
Aster Gdem ◽  
Ground Control Points ◽  
Digital Elevation ◽  
Vertical Accuracy

This study investigates the accuracy of various DEMs (SRTM DEM, ASTER GDEM, and ALOS PALSAR DEM) for the area of the designing Pskom water reservoir (recommended to construction in Pskom River, in Tashkent region. DEMs are compared for the study area using the Global Mapper application and selection Ground Control Points (GCP). The RMSE we calculate is the most easily interpreted statistic as the square root of the mean square error because it has the same units as the quantity drawn on the vertical axis. Results show that SRTM based measurements of ground control points (GCPs) exhibit RMSE of 15.72 m while ASTER DEM based measurements exhibits and RMSE of 18.47 m, ALOS PALSAR exhibit RMSE of 14.02 m for the Water reservoir located in the plain. There are AOS PALSAR outperforms SRTM and ASTER DEM in detecting vertical accuracy. Based on the capabilities of the Global Mapper program, we can build the longitudinal profile of the approximate location where the dam can be built in each DEM and compare. The results obtained show that the dam height is 187 m at ALOS PALSAR DEM, 168 m at ASTER GDEM, and 175 m at SRTM. The study found that using ALOS PALSAR data in the design of the proposed Pskom Reservoir for construction leads to a more accurate result. Comparing the DEMs data shows that there is more difference between the vertical accuracy; the horizontal accuracy level is almost the same. The results were obtained using ALOS PALSAR data in determining the storage volume (W=479368568 m3) and area (F=8.31 sq., km) of the water reservoir.

COMPARATIVE ANALYSIS OF ASTER DEM, ASTER GDEM, AND SRTM DEM BASED ON GROUND-TRUTH GPS DATA

2015 ◽  
Vol 76 (1) ◽  
Author(s):  
Komeil Rokni ◽  
Anuar Ahmad ◽  
Sharifeh Hazini
Keyword(s):  
Ground Truth ◽  
Ground Control ◽  
Control Points ◽  
Pixel Size ◽  
Dual Frequency ◽  
Srtm Dem ◽  
Aster Gdem ◽  
Ground Control Points ◽  
Stereo Imagery ◽  
Aster Image

This study aims to compare the accuracies of ASTER DEM, ASTER GDEM, and SRTM DEM for the area of Universiti Teknologi Malaysia (UTM) and surrounding. In doing so, a number of Ground Control Points (GCPs) were collected using GPS technology and used to generate an absolute DEM using the ASTER stereo imagery. Moreover, two well-known DEMs including ASTER GDEM and SRTM DEM were obtained for the same area with ASTER image. Subsequently, several high accuracy ground-truth points were established around UTM using dual frequency GPS and used to assess the accuracies of the obtained DEMs. The results indicate that an elevation Root Mean Square Error (RMSE) of ±14.86m is achieved for the generated ASTER DEM, which is less than the 15m pixel size of ASTER image. The results further show that the elevation RMSEs of the ASTER GDEM and SRTM DEM are respectively ±4.52m and ±4.14m for the study area. The results illustrate although the resolution of SRTM DEM is much lower than ASTER GDEM, it could provide higher elevation accuracy. Finally, although the accuracy of the ASTER DEM in this study is not high in comparison with the accuracies of ASTER GDEM and SRTM DEM, based on the selected number of check points and resolution of ASTER image, it could be useful for various geoinformation applications.

SRTM DEM-Aided Mapping Satellite-1 Image Geopositioning Without Ground Control Points

2017 ◽  
Vol 14 (11) ◽  
pp. 2137-2141 ◽  
Author(s):  
Xiaowei Chen ◽  
Baoming Zhang ◽  
Minyi Cen ◽  
Haitao Guo ◽  
Tonggang Zhang ◽  
...  
Keyword(s):  
Ground Control ◽  
Control Points ◽  
Srtm Dem ◽  
Ground Control Points
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