Proposed National Geodetic Datum in Palestine

1. Proposed National Geodetic Datum in Palestine Dr Ahmad Taha Diploma, B.A, M.Sc & PhD (Nottingham University-UK) An-Najah National University Geography Department, Nablus, Palestine Eng. Ahmed Madi and National Geodetic Team Palestinian Land Authority The 11th International Congress of GIS and GeoSpace Applications, Geo-Tunis LAICO Hotel: YasmineHammamet, Tunisia from 25 to 29 April 2017

2. Presentation Structure • Overview • Evaluation of Control Points • Proposed National Geodetic Datum in Palestine • Conclusions • Acknowledgments

3. Overview • British Survey of Palestine during 1920 - 1948 results in the establishment of horizontal and vertical networks • Horizontal Network: consists of several thousands of points distributed in Palestine in different orders. • Chain was used in measurement of baseline • Theodolite was used in measurement of angles • Vertical Network: • Precise leveling – few points • Trigonometric leveling – elevation for horizontal points

4. Overview: Survey of Palestine The Major Triangulation system in Palestine (left) and measurement taken from point 2M of the Palestine Major triangulation base line (right). Palestine 426X109km 27,365 km2 Source: http://www.pef.org.uk/monographs/the-survey-of-palestine-under-the-british-mandate-1920-1948 (14-05-2010)

5. Overview: Survey of Palestine The Major Triangulation points in West-Bank (32 points - Left) and Second order points (≈300 points - Right). From North to South ≈137km and East West ≈57km. West Bank: 5,565 km2 20.33% Gaza 364 km2 1.33%

6. Overview: Survey of Palestine Available Bench mark points in north of West-Bank (≈ 60 points -left) and British trigs (6,600 point) & Jordanian trigs (1,450 point) (right).

7. Evaluation of Control Points • West Bank Check conducted by Surveying Department Team. • About 40 points used. • Network RTK (VRS)system used. • Maximum error: E=1.90m, N= 0.70m • Error Range: E=0.80m, N= 1.00m

8. Evaluation of Control Points • Local Check (in Nablus District) • GNSS receiver in Real Time Kinematic (RTK) was used.

9. Evaluation of Control Points • British Network • Assessment of Trig Points:

10. Evaluation of Control Points • British Network • Assessment of Trig Points:

11. Evaluation of Control Points • British Network • Assessment of Trig Points:

12. Evaluation of Control Points • Jordanian Network • Densification of the British Horizontal Network using Theodolite

13. Evaluation of Control Points • During Israel Occupation • Densification of the British Horizontal Network using Traverse • Accumulated error • Allowed error in traverse of 3582.87m is 2.35m

14. Evaluation of Control Points • During Palestinian Authority • Still use traverse • Start using GPS • Every surveyor measures a polygon in his area • Israel GPS companies compute 7 transformation parameters • Example: Ramallah and Bethlehem parameters

15. Evaluation of Control Points How errors affect our life? Cause large errors in property boundaries and accumulated errors in engineering projects.

16. Proposed National Geodetic Datum in Palestine There is a serious need to establish a precise National Geodetic Network (Palestine Grid 2017 – PG17) to replace the traditional networks with a superior GPS-based solution.

17. Proposed National Geodetic Datum in Palestine Previous Work • In 1999, Ordnance Survey (OS) team, from the U.K., have a reconnaissance visit and they recommended to establish a new geodetic network for West Bank and Gaza. • In 2000, Norway Mapping Palestine project: • Measured two polygons: one in Nablus and the other in Ramallah. • The result of this work was a list of adjusted coordinates based on the current coordinates system. • They recommended to carry on similar work in Jenin, Tulkarim, Qalqilia and Hebron.

18. Proposed National Geodetic Datum in Palestine Background: • GPS provides with 3D Cartesian coordinates in WGS84 system (Xwgs84,Y wgs84,Z wgs84). • Define reference Ellipsoid. • Transform GPS coordinates to Local system (Xlocal, Y Local, Z Local). Need to compute 7 transformation parameters. • Define a map projection. • Convert Local coordinates to Grid coordinates (E,N, h). Need to define projection parameters. • We need a Geoid undulation datum to covert ellipsoidal height (h) to orthometric height (H).

19. Proposed National Geodetic Datum in Palestine Reference Ellipsoid • Ellipsoid parameters: • a: semi-major axis • b: semi-minor axis • or f: flattening , f=(a-b)/a • f expressed as 1/f • Old System: Clarke 1880 Palestine • (a=6378300.789m, 1/f= 293.466) • New System: WGS84 datum surface • (a = 6378137.00m, 1/f=1/298.257223563)

20. Proposed National Geodetic Datum in Palestine Bursa-Wolf Model (Helmert Transformation) • Measure several points: 1st & 2nd order • Compute 7 transformation parameters • 3 translation: ∆X, ∆Y, ∆Z • 3 rotation: Rx, Ry, Rz • Scale: S

21. Proposed National Geodetic Datum in Palestine Projection Type • Old System: Cassini Soldner • New System: Transverse Mercator which is best suited for north–south areas like Palestine • Central Meridian (main datum point): as in the old projection, crosses through Jerusalem (82M) • New Zero at 34˚00’00”E, 29˚00’00”N to avoid negative values in the south • Main grid point values • False Easting (m): 170251.5545 (old), ≈114600.00 (New) • False Northing(m): 126867.9090 (old), ≈305000.00(New) • New Grid Scale factor: 1.0000067

22. Proposed National Geodetic Datum in Palestine

23. Proposed National Geodetic Datum in Palestine Vertical Datum • Can be either Ellipsoid or Geoid • GPS measures Ellipsoid Height • Need Geoid Undulation: Global Models (EGM08 … ) integrated by BMs

24. Proposed National Geodetic Datum in Palestine Field work: Stage 1:Building First Order Control Points • Measure several control points (30-40 km) distributed all over West-Bank using GPS. (proposed 6 points). Static GPS for 8 hours. • Tie into the International Terrestrial Reference Frame (ITRF2008). • These points will form the first order control points of the new system. • Repeat measurement each month (for 6 months) to check local movement. • Elevation carried out by precise leveling in least squares solution from original benchmarks. ( 3d control)

25. Proposed National Geodetic Datum in Palestine Stage 2:Densification of Second Order Control Points • Proposed 10 points in each district (110 points) • Densification of passive and active stations. Static GPS for 2 hours. • The passive stations consists of publicly accessible control points. • The active stations consists of permanent GPS reference stations. • The data from the active stations can be used to produce a real time positioning through a Virtual Reference Station System (VRS) • Elevation carried out by precise leveling in least squares solution from original benchmarks. ( 3d control)

26. Proposed National Geodetic Datum in Palestine Stage 3:Measuremnts of BMs (Height Reference System - HRS) • Measure available Bench Marks using Static GPS for 2 hours. • The densification data will be from global Geoid model ( EGM2008) • The integration will be done using finite elements methods to make the global models fit the local datum of Palestine. • The Palestinian areas will be divided into patches to define local datum. • Interpolation using small elements with continuity conditions. • Software : www.dfhbf.de

27. Proposed National Geodetic Datum in Palestine What have been done so far? • Form a National Geodetic Team to decide new surveying standards and to organize all surveying issues in Palestine. • Start Planning the location of the control points. • Start gathering some observations for evaluation purposes. • Fund of $1.7 millions from State of Palestine for Surveying Department to establish the New Geodetic Datum.

28. Proposed National Geodetic Datum in Palestine What have been done so far? • A home made software called Najah Surveying Suite (NSS) has been developed to compute the 7 transformation parameters using least squares.

29. Conclusions • Large errors up to 190cm in the horizontal control points and up to 20cm in the vertical controls. • Accumulated errors can affect our life seriously and caused large errors of more than 1.0m. • Solution for such errors can be through the establishment of new National Geodetic Datum in Palestine. • Parameters of the proposed Palestine Grid 2017 (PG17) have been determined. • Planning and preparation stages have been started.

30. Acknowledgments I would like to thank the National Geodetic Team for their corporation. Special thanks goes to Dr Ahmad Ra’fat for his unlimited support. Many thanks go to the wonderful team of Taha Surveying, especially Mr Ashraf Qadus, for the hard work in the local data collection.

31. National Geodetic Team: Dr Ahmad Taha Dr. Ghadi Younis Eng. Ahmed Madi Eng. Saed Idais Eng. Ghada Awad Eng. Sameh Khleef Eng. Sadeq Abu Zanoon Eng. Hamza Teerawi Eng. Mohammad Maraheel Mr. Bassam Nada Mr. Saber Bodeer

32. Thank you