Assessment of ArcGIS based extraction of geoidal undulation compared to National Geospatial Intelligence Agency (NGA) model – A case study

2020 ◽  
Vol 14 (1) ◽  
pp. 77-81
Author(s):  
Sher Muhammad ◽  
Lide Tian
Keyword(s):  
Geographic Location ◽  
Satellite System ◽  
Orthometric Height ◽  
Geoidal Undulation ◽  
Intelligence Agency ◽  
Mountainous Regions ◽  
Digital Elevation ◽  
Orthometric Heights ◽  
Proper Estimation ◽  
Global Navigation Satellite

AbstractGlobal Navigation Satellite System (GNSS) and remote sensing Digital Elevation Models (DEMs) represent earth’s surface elevation with reference to ellipsoid and orthometric heights. Proper estimation of the geoid (difference of ellipsoid and orthometric heights) is necessary before comparing data referenced to the different vertical datum. In this paper, an error in estimating EGM96 orthometric height is highlighted, verified by NGA/NASA developed model and MATLAB®. A significant error was found in the ArcGIS derived EGM96 orthometric heights range between ±6.9 meters. In addition, interpolation of low-resolution geoid data also produces significant biases depending on geographic location and the number of the interpolation data point. The bias was maximum negative in the central part of Tibetan Plateau and Himalaya. Therefore, estimation of orthometric height similar to NGA/NASA model precision is necessary for comparison of DEMs for natural resources management, 3D modelling and glaciers mass balance mainly in the mountainous regions.

Demarcation of Levees in Irrigated Rice Fields: Laser Technology vs. GNSS-RTK

2019 ◽  
Vol 35 (3) ◽  
pp. 431-437 ◽  
Author(s):  
Marcos Valle Bueno ◽  
Alexssandra Dayane Soares de Campos ◽  
Jaqueline Trombetta da Silva ◽  
Lessandro Coll Faria ◽  
Fabrício da Silva Terra ◽  
...  
Keyword(s):  
Precision Agriculture ◽  
Production Systems ◽  
Water Layer ◽  
Satellite System ◽  
Rice Fields ◽  
Laser Technology ◽  
Technological Advances ◽  
Digital Elevation ◽  
Elevation Model ◽  
Global Navigation Satellite

Abstract. Levees are small land dikes made every rice-cultivation season that allow for flood irrigation in rice fields. Currently, levees are demarcated by utilizing a laser technology (LT) system. However, with current technological advances, the demarcation of levees with the Global Navigation Satellite System (GNSS) and real-time kinematics (RTK) correction has been highlighted in rice production systems in southern Brazil. The objective of this study was to compare the performance between LT and GNSS-RTK systems applied in the demarcation of levees that are used in flooded rice fields. To this end, an experimental area of approximately 27 ha located in Jaguarão, Rio Grande do Sul, Brazil, was used. From a digital elevation model, the area was subdivided into three subareas according to the mean slope: flat (0.16%), intermediate (0.36%), and gently undulated (1.3%). The total length of the levees for the three subareas was 8 km. The relative performances of both demarcation systems were evaluated by analyzing the vertical and horizontal behavior of the levees and the water layer spatial distribution. The results indicated that the demarcation of levees by GNSS-RTK systems is more accurate than that by the LT system, especially in flat areas. In these areas, the GNSS-RTK demarcation system permits a reduction in the total number of levees, as well as an increase in the vertical equidistance between levees and/or an increase in the height of the levee itself. The length of the levee is shorter than in a demarcation using the GNSS-RTK system. Keywords: Contour line, Irrigation, Lowlands, Precision agriculture.

scholarly journals Is GNSS real-time positioning a reliable option to validate erosion studies at olive grove environments?

2020 ◽  
Vol 18 (2) ◽  
pp. e0204
Author(s):  
María S. Garrido-Carretero ◽  
María I. Ramos-Galán ◽  
María C. De Lacy-Pérez de los Cobos ◽  
Sergio Blanca-Mena ◽  
Antonio J. Gil-Cruz
Keyword(s):  
Low Cost ◽  
Satellite System ◽  
Single Frequency ◽  
Olive Grove ◽  
Dual Frequency ◽  
Significance Level ◽  
Digital Elevation ◽  
Significant Difference ◽  
Spatial Redistribution ◽  
Global Navigation Satellite

Aim of study: Soil degradation in agricultural areas is a widespread problem. In this framework, a data validation methodology is presented, including a study of the spatial resolution of Global Navigation Satellite System (GNSS) measurements, the calculation of erosion/deposition models, and the contribution of dual frequency and low-cost single frequency GNSS receivers.Area of study: A test olive grove in SE Spain.Material and methods: The study is based on three observation campaigns, between 2016 and 2018, using different GNSS receivers and working modes. The comparison between different surveys provide the volumetric variation over the analyzed period.Main results: Considering the dual-frequency receiver, there was no statistically significant difference between the means and the variances from 1.5 m and from 4.5 m data resolution at the 0.05 significance level. In order to estimate vertical differences from successive GNSS campaigns a differential digital elevation approach was applied. Although the differences depended on the zone of the test area and they changed along the monitoring period, the erosion rate could be catalogued as very low. The dual-frequency receiver satisfied the vertical centimetric precision limits for high accurate Digital Elevation Model (DEM), making it a reliable and accurate option to validate erosion studies in small areas.Research highlights: The results have allowed the characterization of multi-annual spatial redistribution of the topsoil at local scale, being of great help to design future prevention actions for the “tillage erosion” in olive grove environments. However, more tests are needed to guarantee the feasibility of low-cost receivers.

scholarly journals Large-scale map and 3D modelling of the Henryk Arctowski Polish Antarctic Station

Polar Record ◽  
2017 ◽  
Vol 53 (3) ◽  
pp. 280-288 ◽  
Author(s):  
Mariusz Pasik ◽  
Maria Elżbieta Kowalska ◽  
Sławomir Łapiński ◽  
Marcin Rajner ◽  
Krzysztof Bakuła
Keyword(s):  
Laser Scanning ◽  
Large Scale ◽  
Satellite System ◽  
Scientific Activity ◽  
3D Modelling ◽  
Future Research ◽  
Digital Elevation ◽  
The Mean ◽  
Elevation Model ◽  
Global Navigation Satellite

ABSTRACTThis paper presents survey measurements carried out during the 39th Polish Antarctic Expedition to the Henryk Arctowski Polish Antarctic Station in March 2015. The measurements were used to create a map on a 1:500 scale and for 3D modelling of the station buildings and vicinity. The paper also presents the geodetic control network established around the station. We discuss the issue of creating a digital elevation model for the station and its surroundings. The elevation models were generated using terrestrial laser scanning data integrated with Global Navigation Satellite System real time kinematic and tacheometric surveying. The accuracy of these models was estimated using height differences in relation to survey data. The mean height difference was 0.03 m and root mean square error was 0.05 m. Furthermore, an analysis of changes to the coastline was conducted using archival cartographic materials to assess the threat of Admiralty Bay to the station buildings. The results are important for continued scientific activity and safety at Arctowski Station, and may be useful for future research on King George Island.

scholarly journals Evaluation of Uncrewed Aircraft Systems’ Lidar Data Quality

2019 ◽  
Vol 8 (12) ◽  
pp. 532 ◽  
Author(s):  
Benjamin J. Babbel ◽  
Michael J. Olsen ◽  
Erzhuo Che ◽  
Ben A. Leshchinsky ◽  
Chase Simpson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Laser Scanning ◽  
Satellite System ◽  
Precision Data ◽  
The Road ◽  
Aircraft Systems ◽  
Accuracy And Precision ◽  
Digital Elevation ◽  
Elevation Model ◽  
Global Navigation Satellite

Uncrewed aircraft systems (UASs) with integrated light detection and ranging (lidar) technology are becoming an increasingly popular and efficient remote sensing method for mapping. Due to its quick deployment and comparatively inexpensive cost, uncrewed laser scanning (ULS) can be a desirable solution to conduct topographic surveys for areas sized on the order of square kilometers compared to the more prevalent and mature method of airborne laser scanning (ALS) used to map larger areas. This paper rigorously assesses the accuracy and quality of a ULS system with comparisons to terrestrial laser scanning (TLS) data, total station (TS) measurements, and Global Navigation Satellite System (GNSS) check points. Both the TLS and TS technologies are ideal for this assessment due to their high accuracy and precision. Data for this analysis were collected over a period of two days to map a landslide complex in Mulino, Oregon. Results show that the digital elevation model (DEM) produced from the ULS had overall vertical accuracies of approximately 6 and 13 cm at 95% confidence when compared to the TS cross-sections for the road surface only and road and vegetated surfaces, respectively. When compared to the TLS data, overall biases of −2.4, 1.1, and −2.7 cm were observed in X, Y, and Z with a 3D RMS difference of 8.8 cm. Additional qualitative and quantitative assessments discussed in this paper show that ULS can provide highly accurate topographic data, which can be used for a wide variety of applications. However, further research could improve the overall accuracy and efficiency of the cloud-to-cloud swath adjustment and calibration processes for georeferencing the ULS point cloud.

scholarly journals Verification of the Jakarta Geoid Model from the Gravity Data of 2.5 km Resolution with Gravimetric Geoid

2021 ◽  
Vol 873 (1) ◽  
pp. 012045
Author(s):  
D Ramdani ◽  
A N Safi’i ◽  
P Hartanto ◽  
N Oktaviani ◽  
M I Hariyono
Keyword(s):  
Gravity Data ◽  
Geoid Undulation ◽  
Satellite System ◽  
Orthometric Height ◽  
Geopotential Model ◽  
Gravimetric Geoid ◽  
Geoid Model ◽  
Speed Up ◽  
Global Navigation Satellite ◽  
Stokes Kernel

Abstract To use the Global Navigation Satellite System (GNSS) correctly, the height information should be transformed into orthometric height by subtracting geoid undulation from it. This orthometric height is commonly used for practical purposes. In 2015 geoid of Jakarta has been produced, and it has an accuracy of 0.076 m. In the year 2019, airborne gravimetry has been done for the entire Java Island. The area of DKI Province cannot be measured because there is inhibition from Airnav. For this reason, terrestrial gravimetric measurements are carried out in this region by adding points outside the previously measured area. To compute the geoid in the Jakarta region is needed the Global Geopotential Model (GGM). In this paper, the GMM used is gif48. The “remove and restore” method will be used in calculating the geoid in this Jakarta region. Besides that in this geoid calculation also uses Stokes kernel and FFT to speed up the calculation. The verification of the resulting geoid is carried with 11 points in DKI Jakarta Province. This verification produces a standard deviation of 0.116 m and a root mean square of 0.411 m.

scholarly journals Calculating of adjusted geoid undulation based on EGM08 and mean sea level for different regions in Iraq

2018 ◽  
Vol 162 ◽  
pp. 03028 ◽  
Author(s):  
Ali Fanos ◽  
Rusul Tahir ◽  
Suad Mohammed ◽  
May Mahmood
Keyword(s):  
Global Positioning System ◽  
Engineering Application ◽  
Geoid Undulation ◽  
Satellite System ◽  
Geodetic Survey ◽  
Transformation Process ◽  
Orthometric Height ◽  
Geoid Model ◽  
Global Positioning ◽  
Global Navigation Satellite

In last decades Global Navigation Satellite System (GNSS) or as known Global Positioning System (GPS) technique is considered a revolutionary technique in the field of geodetic survey in comparison with traditional techniques (level, theodolite and total station). The height obtained from GNSS technique is ellipsoid height and to have a physical meaning in a surveying or engineering application it must be transformed to orthometric height. Therefore, a geoid model has to be used to do this transformation process. In Iraq there is no specific geoid that can be used in order to get proper orthometric height. This research aims to calculate adjusted geoid undulation based on Earth Gravitational Model 2008 (EGM08) through observation of Iraqi official vertical network using GNSS technique. Different regions in Iraq have been chosen to perform this research. The result of this research can assist a lot to enhance the accuracy of elevations obtained from GNSS and support the establishment of Iraq geoid.

scholarly journals Determining Peak Altitude on Maps, Books and Cartographic Materials: Multidisciplinary Implications

2021 ◽  
Vol 13 (6) ◽  
pp. 1111
Author(s):  
Kamil Maciuk ◽  
Michal Apollo ◽  
Joseph M. Cheer ◽  
Ondřej Konečný ◽  
Krystian Kozioł ◽  
...  
Keyword(s):  
Accurate Determination ◽  
Satellite System ◽  
Common Source ◽  
Mountain Ranges ◽  
Digital Elevation ◽  
Accuracy Of Measurements ◽  
Other Information ◽  
Gnss Receivers ◽  
Automatic Methods ◽  
Global Navigation Satellite

Mountain peaks and their altitude have been of interest to researchers across disciplines. Measurement methods and techniques have changed and developed over the years, leading to more accurate measurements and, consequently, more accurate determination of peak altitudes. This research transpired due to the frequency of misstatements found in existing sources including books, maps, guidebooks and the Internet. Such inaccuracies have the potential to create controversy, especially among peak-baggers in pursuit of climbing the highest summits. The Polish Sudetes Mountains were selected for this study; 24 summits in the 14 mesoregions were measured. Measurements were obtained employing the global navigation satellite system (GNSS) and light detection and ranging (LiDAR), both modern and highly precise techniques. Moreover, to determine the accuracy of measurements, several of the summits were measured using a mobile phone as an additional method. We compare GNSS vs. LiDAR and verify the level of confidence of peak heights obtained by automatic methods from LiDAR data alone. The GNSS receiver results showed a discrepancy of approximately 10 m compared with other information sources examined. Findings indicate that the heights of peaks presented in cartographic materials are inaccurate, especially in lesser-known mountain ranges. Furthermore, among all the mountain ranges examined, the results demonstrated that five of the summits were no longer classed as the highest, potentially impacting tourist perceptions and subsequent visitation. Overall, due to the topographical relief characteristics and varying vegetation cover of mountains, we argue that the re-measuring procedure should comprise two steps: (1) develop high-resolution digital elevation models (DEMs) based on LiDAR; (2) assumed heights should be measured using precise GNSS receivers. Unfortunately, due to the time constraints and the prohibitive costs of GNSS, LiDAR continues to be the most common source of new altitude data.

scholarly journals VALIDATION OF THE DIGITAL ELEVATION MODEL (SRTM) WITH GNSS SURVEYING APPLIED TO THE MIRIM LAGOON HYDROGRAPHIC BASIN

2018 ◽  
Vol 24 (3) ◽  
pp. 407-425
Author(s):  
Patricia Andréia Paiola Scalco ◽  
Andrea Lopes Iescheck ◽  
Iran Carlos Stalliviere Corrêa ◽  
Fernando Comerlato Scottá ◽  
Rafael Mastracusa de Oliveira ◽  
...  
Keyword(s):  
Research Work ◽  
Absolute Error ◽  
Satellite System ◽  
Geopotential Model ◽  
Kinematic Positioning ◽  
Hydrographic Basin ◽  
Digital Elevation ◽  
Vertical Accuracy ◽  
Elevation Model ◽  
Global Navigation Satellite

Abstract Between 2013 and 2014, a kinematic positioning based on the Global Navigation Satellite System (GNSS) was carried out for this research work. This GNSS survey resulted in 275916 points with tridimensional coordinates in the cross-border basin area of 58205 km2 called Mirim Lagoon Hydrographic Basin, located in south of Rio Grande do Sul (Brazil) and west of Uruguay. This study aims at showing the methodology firstly and, furthermore, results regarding the validation of the vertical accuracy of the DEM SRTM through kinematic positioning by GNSS, in the Mirim Lagoon Hydrographic Basin region. Also, the GNSS surveying data was post-processed with the Precise Point Positioning (PPP) method, and the ellipsoidal height was converted into orthometric height through the software INTPT geoid. During this study, the geopotential model (EGM96) was used to transform altitude differences between two countries, Brazil and Uruguay. Results showed that the vertical mean absolute error of the DEM SRTM vary from 0.07 m to ± 9.9m with average of -0.28m. This vertical accuracy is better than the absolute vertical accuracy value of ±16m published in the SRTM data specification and validates the DEM SRTM.

scholarly journals Development of an Integrated Digital Elevation Model for Safe Takeoff and Landing of the Aircraft

2013 ◽  
Vol 48 (4) ◽  
pp. 147-158
Author(s):  
Adam Ciećko ◽  
Wojciech Jarmołowski
Keyword(s):  
Digital Elevation Model ◽  
Inertial Navigation System ◽  
Field Survey ◽  
Shuttle Radar Topography Mission ◽  
Satellite System ◽  
Digital Elevation ◽  
Flight Parameters ◽  
Elevation Model ◽  
Prototype Software ◽  
Global Navigation Satellite

ABSTRACT The article describes preliminary results of the augmentation of Global Navigation Satellite System/Inertial Navigation System positioning (GNSS/INS) by Digital Elevation Model (DEM) based on the data from the Shuttle Radar Topography Mission (SRTM) and data from field survey. The prototype software is developed to refer the position of the aircraft to DEM and informs the user about the current relevant flight parameters. The number of the parameters may be arbitrarily increased, however, currently we investigate the altitude above the terrain and the aircraft position relative to the descent path and airfield. The study provides some information on the local SRTM accuracy in relation to the field survey of the airfield "Dajtki" - Aeroclub of Warmia and Mazury in Olsztyn.

scholarly journals USING SURFACE FITTING AND BUFFER ANALYSIS TO ESTIMATE REGIONAL GEOIDAL UNDULATION

2015 ◽  
Vol 21 (3) ◽  
pp. 624-636 ◽  
Author(s):  
FANG-SHII NING
Keyword(s):  
Geoid Undulation ◽  
Satellite System ◽  
Surface Fitting ◽  
Reference Points ◽  
Surface Model ◽  
Geoidal Undulation ◽  
Surface Models ◽  
Quadratic Surface ◽  
Geodetic Height ◽  
Global Navigation Satellite

Abstract:Geoidal undulation is the distance from the surface of an ellipsoid to the surface of a geoid measured along a line that is perpendicular to the ellipsoid. This paper describes how the geoidal undulation can be derived from the orthometric height, Global Navigation Satellite System geodetic height, and a surface model. Various surfaces fitting using the plane coordinates of the reference points and analysis with different buffers were used to determine the geoid undulation Taiwan. The results show that the quadratic surface model outperformed other surface models, yielding a buffer radius ranging from 15 to 25 km. According to the results, the accuracy of regional geoid undulation (city or state) can be improved through this process of surface fitting

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