%PDF-1.4 % 1 0 obj << /Type /Pages /Count 2 /Kids [ 2 0 R 122 0 R ] >> endobj 2 0 obj << /Type /Page /Parent 1 0 R /Resources << /ProcSet [ /PDF /Text /ImageB /ImageC /ImageI ] /Font << /QuickPDFF4ac22998 77 0 R /QuickPDFF795f0481 121 0 R >> >> /Contents [ 5 0 R ] /MediaBox [ 0 0 595.2756 841.8898 ] /CropBox [ 0 0 595.2756 841.8898 ] >> endobj 3 0 obj << /Type /Catalog /Pages 1 0 R /Metadata 124 0 R >> endobj 4 0 obj << /Producer (Debenu Quick PDF Library 11.15 \(www.debenu.com\)) /Creator (Debenu Quick PDF Library 11.15 \(www.debenu.com\)) /CreationDate (D:20220919115847+02'00') /ModDate (D:20220919115850+02'00') >> endobj 5 0 obj << /Length 3513 /LC /iSQP >> stream 0 Tr /QuickPDFF795f0481 14 Tf 0 0 0 rg 100 Tz 0 Tw 0 Tc 0 Ts BT 1 0 0 1 60.0228 770.8329 Tm (Transformation of Global to Local Geoid for Regional Geoid Modeling: Results)Tj 1 0 0 1 218.6988 752.1709 Tm (from Enugu State, Nigeria)Tj ET /QuickPDFF795f0481 11 Tf 0 0 0 rg BT 1 0 0 1 155.2483 717.2179 Tm (Francis Okeke, Victor Nnam and Joseph Odumosu \(Nigeria\))Tj ET /QuickPDFF795f0481 11 Tf 0 0 0 rg BT 1 0 0 1 56.6929 675.188 Tm 14.663 TL (Key words: )' ET /QuickPDFF4ac22998 11 Tf 0 0 0 rg BT 1 0 0 1 141.7323 675.188 Tm 14.454 TL (Engineering survey; Geoinformation/GI; Reference frames; Reference systems; Remote)' (sensing; LONG WAVELENGHT GEOID, VERTICAL REFERENCE SYSTEMS\(VRS\),)' (VERTICAL REFERENCE FRAMES\(VRF\), TRANSFORMATION OF GLOBAL TO)' (LOCAL GEOID \(TGL\), ROOT MEAN SQUARE ERROR \(RMSE\), NIGERIAN)' (GEOLOGICAL AGENCY \(NGSA\))' ET /QuickPDFF795f0481 11 Tf 0 0 0 rg BT 1 0 0 1 56.6929 590.1487 Tm 14.663 TL (SUMMARY)' ET /QuickPDFF4ac22998 10 Tf 0 0 0 rg BT 1 0 0 1 56.6929 150.7097 Tm 13.14 TL (__________________________________________________________________________________________)' ()' (Transformation of Global to Local Geoid for Regional Geoid Modeling: Results from Enugu State, Nigeria \(11335\))' (Francis Okeke, Victor Nnam and Joseph Odumosu \(Nigeria\))' ()' (FIG Congress 2022)' (Volunteering for the future - Geospatial excellence for a better living)' (Warsaw, Poland, 1115 September 2022)' ET /QuickPDFF4ac22998 11 Tf 0 0 0 rg BT 1 0 0 1 56.6929 561.8022 Tm 14.454 TL (ABSTRACT)' ()' (Regional geoid modelling is an age-long problem in geodesy. Over the years the gravimetric and geometric)' (methods of geoid modeling stand out as the most preferred and utilized methods. However, due to several)' (factors ranging from lack of sufficient gravity data, poor integrity of available gravity data, parametric)' (inconsistencies in adopted national Vertical Reference Systems, improper definition of national height datum)' (e.t.c, the use of both methods especially in developing countries is equivocal. Recently, the spatial resolution)' (and accuracy of global geoid models \(GGM\) are improving for all parts of the world thus addressing the)' (problems of availability, consistency and resolution of data. Therefore, this study proposes a low-cost)' (method of geoid modelling, wherein the regional geoid model is obtained by transforming the global geoid to)' (local geoid. The Transformation of Global to Local \(TGL\) geoid method is based on the concept of)' (transforming ellipsoidal heights and geoidal undulations between various datums. The method was tested in)' (Enugu state of Nigeria and the results obtained were compared with the Geometric and Gravimetric Geoid)' (models. A total of 25 control points with known Ortometric heights and evenly distributed across the study)' (area were used for comparing the results obtained from the three methods. Statistical analysis of the results)' (obtained shows high level of consistency between the three \(3\) methods. Furthermore, Root Mean Square)' (Errors of 0.123 m and 0.389 m were obtained between the Geometric method and the TGL then)' (gravimetric methods respectively when compared with known orthometric heights at control points. The)' (TGL method is recommended as a reliable alternative for regional geoid modeling in areas where funds are)' (unavailable for rigorous gravity observations.)' ()' (Keywords: Long wavelength geoid; Stokes function; GNSS / Levelling geoid; Vertical Reference )' ET endstream endobj 6 0 obj << /Length 316 /Filter /FlateDecode >> stream xMRKnCAۿSpk`y^Uu[jIɒT%C/:b}Rx\%=
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