This our presentation in 2016 best projects ceremony. It was very nice to be selected among all these projects.

1. GeoidApp: A unified Framework for
Geoid Computations
Mohamed Jaafar and Mohamed Yousif
{mmbusif,wadjaafar}@gmail.com
Supervised by:
Ahmed Abdalla

2. Objective of the thesis
● Evaluation of GRACE/GOCE GGM on Sudan
● GeoidApp: A Unified Framework for Geoid Computations

3. Satellite
Gravimetry
● Restoring unsurveyed areas of
the Earth’s gravity field
● Studying the time-variable
variations of the Earth’s gravity
field
● Studying the effects of the
climate change and the
variation of the ground water
content
● Compute the geoid (or datum)
Is important because

4. Unsurveyed areas
Ahmed (2008)

5. New dedicated Satellite Missions
● CHAMP (CHAllenging Mini-Satellite Payload)
● GRACE (Gravity Recovery And Climate Experience)
● GOCE (Gravity Field and Steady-State Ocean Circulation Explorer)

6. Input data-GPS/leveling
Point distribution-Khartoum 24pts

7. Proposed Datums for Sudan
Datum Name Date Type GGM Degree/order
Mohamed
Osman
1967 Astro-geodetic Deflection of vertical N/A
Fashir 1991 Gravimetric GEM-T1 36
Ahmed Abdalla 2008 Gravimetric EIGEN-GRACE02S 150
Walyeldeen
Godah
2014 Gravimetric GO_CONS_GCF_2_TIM_
R4 (TIM-R4)
250

8. Global Geopotential Models
Name Release Date Max degree and order
ITU_GGC16 2016 280
ITU_GRACE16 2016 180
GECO 2015 2190
EIGEN-6C4 2014 2190
EGM2008 2008 2190

9. Our study
We have evaluated
GECO, EGM2008, EIGEN-6C4,
ITU_GGC16, and ITU_GRACE16
Big models were evaluated at
each 5 degrees
Small models (ITU_GGC16,
ITU_GRACE16) were evaluated
at each degree
The models were evaluated on
two datasets
We have tested each model to
the maximum d/o

10. Evaluation on
GPS/leveling data

11. Our Results
1. We have evaluated our models
using GPS/leveling data
2. With accuracy of 0.365m,
ITU_GGC16 was the best model
(at degree 149)
3. It is even comparable to that of
Ahmed and Walyeldeen (0.29,
0.306)

12. Comparison with similar works
STD [m]
Name (Year) Before Fitting After Fitting
(7-parameters)
KTH-SDG08 (2008) 0.576 0.29
SUD-GM2014
(2014)
0.644 0.306
GeoidApp (2016) 0.365 N/A

13. 40%
Improvement compared to Ahmed (2008) and Walyeldeen (2014)

14. 100Km Road Survey Costs
15 days Campaign
Requirement Cost (SDG)
2 Engineers 30,000
3 Workers 9,000
GPS Device 18,000
Optical Level 1,050
2 Cars 30,000
20 Control Points 2,000
Fuel 2,400
Subsistence
costs
5,775
Data Processing 52,000
Total 150,225
Using Spirit leveling
Very expensive :(

15. 100Km Road Survey Costs
15 days Campaign
Requirement Cost (SDG)
1 Engineer 15,000
1 Worker 3,000
GPS Device 18,000
1 Car 15,000
Fuel 1,200
Subsistence
costs
1,650
Data Processing 47,000
Total 100,850
Our approach
Saves 31.5% :)

16. Requirement Cost (SDG)
2 Engineers 30,000
3 Workers 9,000
GPS Device 18,000
Optical Level 1,050
2 Cars 30,000
20 Control Points 2,000
Fuel 2,400
Subsistence
costs
5,775
Data Processing 52,000
Total 150,225
Requirement Cost (SDG)
1 Engineer 15,000
1 Worker 3,000
GPS Device 18,000
1 Car 15,000
Fuel 1,200
Subsistence costs 1,650
Data Processing 47,000
Total 100,850

17. Meet GeoidApp

18. Similar works
● EGMLab Kiamehr et. al (2008)
○ It’s no longer maintained. Limited to max. d/o 720
● ICGEM calculation service
○ Web-based app. Includes so many geopotential functionals. Grid mode only
○ Three works simultaneously
● GeographicLib
○ Uses only EGM84, EGM96, and EGM2008
○ Extremely limited and outdated

19. GeoidApp ● Generic
● Easy to use
● Highly optimized
● Researchers and end-users
friendly
GeoidApp was developed to

20. GeoidApp general workflow

21. Output files from GeoidApp
A typical project in GeoidApp has this structure
- Model Name
- model_name_results.csv
- model_name.log
- model_table.txt
- Report
- report.{html,pdf,tex}
- Figures

22. GeoidApp Suite
● Desktop Application
● An Android Application

23. We give
researchers, and
Enterprises a
software with an
unprecedented
experience

24. Summary
● We proposed a new reference surface for Sudan
● GeoidApp is a general framework for “geopotential
functionals”