Determination of the local geoid model in Duhok Region, University of Duhok Campus as a Case study

Abdulrahman, Farsat Heeto

doi:10.1016/j.asej.2020.10.004

Cited by 11 publications

(6 citation statements)

References 14 publications

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“…For example, Erol and Çelik (2004b) achieved an accuracy of about 0.03 m using UK as an interpolation method, and 1 GHP/3 km. Abdulrahman (2021) achieved an accuracy of about 0.243 m using OK and 1 GHP/0.350 km, but in this case measurements are carried out by means Total Station (Trigonometric Levelling).…”

Section: Resultsmentioning

confidence: 99%

On the Accuracy of Geoid Heights Derived from Discrete GNSS/Levelling Data Using Kriging Interpolation

Alcaras

Amoroso

Falchi

et al. 2022

International Association of Geodesy Symposia

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Local geoid models presenting higher resolution than global ones are generally derived by a combination of different datasets, integrating individual pure astrogeodetic, gravimetric and GNSS/levelling solutions. To define local geoid, different interpolators may be applied starting from dataset of geoid height values. It is well known that the accuracy of the resulting models depends not only by interpolation method, but also by points numerosity and distribution. This article aims to analyse the performance of Kriging approaches in dependence of the density of the dataset. The experiments are carried out on geoid heights extracted in random way from an already existing local geoid model: different subsets are organized containing an increasing number of points in the same area and each of them is submitted to Kriging interpolations (Universal Kriging and Ordinary Kriging). The resulting models are compared with the original one and residuals are calculated to evaluate the accuracy in dependence of point density. The results demonstrate the efficiency of the Kriging methods, highlighting the possibility to achieve higher accuracy (a few centimetres) using a point density of 1 point/100 sqkm, in absence of gravity anomalies. Ordinary Kriging provides better results than Universal Kriging but the undulations between the resulting models are minimal (a few millimetres) when a high number of points is involved. Furthermore, the results highlight the limit of the leave one out Cross validation since it supplies higher residuals than direct comparison for both Universal Kriging and Ordinary Kriging, when few points are used.

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Section: Resultsmentioning

confidence: 99%

On the Accuracy of Geoid Heights Derived from Discrete GNSS/Levelling Data Using Kriging Interpolation

Alcaras

Amoroso

Falchi

et al. 2022

International Association of Geodesy Symposia

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“…Some of these methods include linear interpolation, kriging, triangulation, natural neighbor, Inverse Distance Weighting (IDW), and polynomial regression [24,25]. In [17], various surface modeling techniques were employed, including nearest neighbor, natural neighbor, and IDW.…”

Section: Wwwetasrcom Ali: Making Different Topographic Maps With the ...mentioning

confidence: 99%

“…In the field of geodetic surveying, the GPS is a highly developed technique. The GPS method is significantly more effective than more similar methods, including total station, level, and theodolite, in terms of the number of users, effective cost, inter-visibility, and accuracy [17][18][19][20]. Authors in [21] proved that produced DEM using DGPS data are more effective than DEM produced using contour separation or SRTM data.…”

Section: Introductionmentioning

confidence: 99%

Making Different Topographic Maps with the Surfer Software Package

Ali

2024

Eng. Technol. Appl. Sci. Res.

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The main objective of this study is to describe the preparation of topographic maps using the Surfer software. A total of 159 regularly distributed Ground Control Points (GCPs) were collected with the use of the Differential Global Positioning System (DGPS). Seven methods (Contour Map, Post Map, 3D Surface Map, 3D Wireframe Maps, Grid Vector-1 Map, Color Relief Map, and Shaded Relief Maps) at the Surfer environment were used to prepare the topographic maps at the Mukhtar Village near the Al-Fallujah City. Contour lines with other features were superimposed on the DEM layer, which refers to the topography of the terrain inside this study area. The accuracy of the database's results was estimated, essential maps were given, and the results were efficient and effective. The most appropriate method to represent topographic maps was proposed, each of these techniques has been enough to provide us with a general understanding of the subject area.

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“…The Mean Error (ME), the Root Mean Square Error (RMSE), and the Standard Deviation (SD) are examples of these indicators (Peprah et al, 2017). The Root Mean Square Error (RMSE) is used to check the accuracy of the variations between a computed or measured value and an estimated value (Abdulrahman, 2021).…”

Section: Evaluating the Performance Of Earth Gravitational Models (Egms)mentioning

confidence: 99%

Evaluation of EGM96 and EGM08 based on GPS/Levelling Heights in Egypt

Aziz¹,

Rashwan²,

Saba³

2023

SA J of Geomatics

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The heights determined by Global Positioning System (GPS) refer to the ellipsoid called the World Geodetic System 1984 (WGS84). Global Geopotential Models (GGMs) that are available on GNSS commercial software are generally used to transform ellipsoidal heights to orthometric heights. In this study, the geoid heights of GPS/Levelling were computed to evaluate the accuracy of the geoid heights obtained from two GGMs, namely, the Earth Gravitational Model 96 (EGM96) and the Earth Gravitational Model 08 (EGM08). Seventeen (17) GPS/Levelling stations of the High Accuracy Reference Network (HARN) over Egypt were used for this purpose. The standard deviations for the differences between the geoid heights obtained through GPS/Levelling and those obtained from EGM96 and EGM08 were determined as ± 1.212 m and ± 0.543 m, respectively. This research confirms that the geoid heights obtained from EGM08 are closer to the geoid heights determined using GPS/Levelling over Egypt.

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Determination of the local geoid model in Duhok Region, University of Duhok Campus as a Case study

Cited by 11 publications

References 14 publications

On the Accuracy of Geoid Heights Derived from Discrete GNSS/Levelling Data Using Kriging Interpolation

On the Accuracy of Geoid Heights Derived from Discrete GNSS/Levelling Data Using Kriging Interpolation

Making Different Topographic Maps with the Surfer Software Package

Evaluation of EGM96 and EGM08 based on GPS/Levelling Heights in Egypt

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