Department of Survey Engineering

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    Evaluation of Unmanned Aerial Vehicle Photogrammetry for Corridor Mapping
    (University of Khartoum, 2018) Abdalwahab Abdalkareem
    ABSTRACT Orthophoto is an important asset for producing and development of contour maps. Conventional methods for generating these maps are terrestrial surveying. They are, however, time consuming and costly. A new approach is needed to rapidly generate orthophoto at a low cost. This study will present how this can be achieved using Unmanned Aerial Vehicles (UAVs); a new remote sensing tool capable of acquiring airborne images which have the potential to provide information with a very high spatial and temporal resolution at a low cost. The main objective of this study was to use UAV imagery to produce a high quality orthophoto to generate contour maps. In order to achieve this, a DJI Phantom 4 Vision Plus quadcopter was used to collect 115 images at a flying height of 90 m over the study area. Using adequate photogrammetric software an orthophoto covering 130,000 square meters was produced. With appropriate ground control points, an absolute positional accuracy of ±6 cm RMSE was achieved and generated dense points cloud. Also, the study area surveyed by automatic level and deferential real time kinematic (RTK) from local Bench Mark (BM) and (GCP) to evaluate the UAV. The final results are points with (E,N,h)coordinate with accuracy ±2cm base on local (GCPs). These points generate the contour maps or digital elevation models (DEM) which is important for designing corridor mapping. This study has demonstrated that UAV is a useful platform for obtaining high-resolution aerial images for generating orthophoto maps at a sustainable cost. ملخص تعتبر الصور من الأشياء المهمة في تطوير الخرائط الكنتورية التي يتم إنتاجها بعدة طرق تقليدية تستخدم فيها أجهزة الميزانية (level) وغيرها من الطرق المكلفة بالإضافة الى أنها تأخذ الكثير من الوقت هذه الدراسة توضح كيف يتم حل هذه الإشكالية و الإستفادة من التقنيات المتوفرة و ذلك بإستخدام طائرات من غير طيار و التي تعتبر أحد تقنيات الإستشعار عن بعد الحديثة والتي يتم فيها إلتقاط صور جوية تحتوي على معلومات بدقة مكانية و زمانية عالية وبأقل تكلفة وفي زمن وجيز. الهدف الأساسي من هذا البحث هو إستخدام صور الطائرات من غير طيار لإناتج الصور المصححة التي يمكن بواسطتها إستخراج الخرائط الكنتورية ولتحقيق هذا الهدف تم إستخدام طائرة (Unmanned aerial Vehicle) لجمع 115 صورة على إرتفاع 90 متر فوق منطقة الدراسة و بإستخدام أحد البرامج تم عمل خطة طيران لتغطية مساحة قدرها 130000 متر مربع وتم إنتاج مجموعة من النقاط ثلاثية الأبعاد (E,N,h) تسمى Dense points cloud بواسطة نقاط تحكم أرضية و بدقة قدرها ±2سم. وأيضا تم إستخراج هذه النقاط بواسطة أجهزة الميزانية و بنقاط بنشماركات محلية للتقييم و المقارنة. الناتج النهائي هو نقاط ثلاثية الأبعاد بدقة±2 سم إعتمادا على نقاط التحكم الأرضية. بواسطة هذه النقاط تم إنتاج الخرائط الكنتورية و نموذج الإرتفاعات الرقمية و التي تلعب دورا مهما في إنتاج الخرائط الطولية هذه الدراسة أثبتت أن الطائرات من غير طيار مفيدة جدا في إنتاج صور مصححة بدقة عالية و تكلفة أقل.
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    Geoid Determination Using Artificial Neural Networks and Geometrical Models
    (University of Khartoum, ) Aborida, Ammar Mohammed Maryod ; Kamal Abdellatif Abdalla Sami ; Department of Surveying Engineering
    The determination of Orthometric heights is important for many task in Engineering, this can be determined by computing the difference between geodetic height and geoid undulation. This relationship is different and unstable from one point to another. In such trend, Artificial Intelligence proved to be useful towards finding solution for problems that could not be solved by traditional techniques. The main objective of this study is to determine an accurate geoid model for Khartoum State. The study adopts a method consisting of three sub methods to model the geoid, the first one is to apply an Artificial Neural network (ANN) to model the Geoid surface using the back propagation algorithm for Khartoum State, through supervised training by using 40 collocated points for training and 6 for test, the second method used kriging to model the Geoid surface for Khartoum State, and finally Compute the coefficients representing the bias∝_0, and tilts of the geoid plane will respect to WGS84 ellipsoid ∝_1 ∝_2 to model the Geoid surface for Khartoum state, and then comparison between these three methods with Earth Gravitational Model 2008. Based on the test results and the statistical analysis carried out in this study a trained Artificial Neural Networks model was found and is tested to be able to estimate Geoid model better than the models generated by interpolation technique (kriging method); and better than coefficients representing the bias and tilts of the geoid plane, and EGM 2008 when applied on Khartoum locality. The average of the discrepancies of the test points calculated were -1.1 cm, -0.7 cm, -0.5 cm, and 28 cm, respectively, for the modeling by ANNs, interpolation, geometrical, and by EGM 2008. The standard deviation of the discrepancies of the test points was ±1.3 cm, ±3.3 cm, ±3.7 cm, and ±4.6 cm, respectively, for the modeling by ANNs, interpolation, geometrical, and by EGM 2008. Thus, the Root Mean Square Errors of the discrepancies of the test points was computed to be ±1.6 cm, ±3 cm, ±3.7 cm, and ±28 cm, respectively, for the modeling by ANNs, interpolation, geometrical, and by EGM 2008, where means that the ANN model is better than the other three models. The study recommends running further studies using other algorithms to train the Artificial Neural Networks.
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    Calculation of the Transformation Parameters between Local and Global Coordinate Systems
    (University of Khartuom, ) Hamza Alhassan Alabbas Alfadul ; Garalnabi Ibrahim Mohamed ; Surveying Engineering
    The main objective of this research was to comparebetween Adindan and WGS84 using three different models: the three translations (ΔX, ∆Y, ∆Z) model, the five Parameters (ΔX, ∆Y, ∆Z,∆a (semi-major axis), ∆f (flattening)) model and the seven Parameters (〖ΔX,∆Y,∆Z,R〗_X,R_Y,R_Z,Δl)model, by calculating the transformation parameters. The data used for this study consisted of 59 common points, four of them were used for the calculation of the parameters, and the rest of the points were used as validation data. Moreover the research investigated the use of the three and five Parameters models as alternatives to the complicated seven Parameters model. The results revealed that the obtained values of parameters were very close to those given by the internationally adopted seven parameters model (≤ 1.5 meter). It can then be concluded that three and five Parameters models can be used instead of seven Parameter model, when the tolerance is less than 1.5 meter.
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    Evaluation of GPS Datum Transformation and GPS/GIS Integration
    (UOFK, 2015-06-28) Abd El Rahim El Gizouli, Mohamed ; Kamal Abd El Latif Abd Alla ; Surveying Engineering
    Civilian and Military uses of geodetic GPS surveying and Geographical Information Systems (GIS) are the main objective of this study. The production of the military used topographical maps in hard and soft copy is the main duty of the Sudan Military Surveying Unit، so that the use of intermediate and long range rockets and missiles requires that the distance and direction from launch site to target be accurately known. With the development of both intermediate and long range weapons systems، geodetic problem has become more critical than ever before. To satisfy military requirements، it is necessary to provide detailed cartographic coverage of areas of strategic importance، and to accomplish geodetic computations between these areas and launch sites which are often on unrelated datums. Both of theses requirements necessitate unification of major geodetic datums by one or a combination of existing methods. Also the geodetic data used in the production of the topographical base maps for any area in Sudan were observed and computed by the classical system related to the local datum (Adindan) using the parameters of Clarke 1880 ellipsoid. Nowadays there are satellite receives (GPS receivers) used in geodetic observations where the data produced by this system are referenced to the geocentric datum (WGS-84). In this thesis the principles of geodesy is introduced in chapter one. The GPS surveyor with some details in the GPS observation systems are given in chapter two. Some information about Geographical Information System (GIS) is outlined in chapter three. The definition of the datum orientations and the datum orientations and the transformation parameters between local and geocentric datum is given in chapter four. Practical application of geodetic GPS coordinates common to the national network stations were examined and the transformation parameters between (WGS-84) and Adindan datum were determined in chapter five، including the evaluation of ARC/INFO (GIS software) using common GPS(WGS-84) and local datum (Adindan) coordinates to examine the accuracy of the topographical maps handled by the GIS. Conclusions and future recommendations were drawn in chapter six.
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    Extraction of Three Dimensional Ground Coordinates Based on Analyical Photogrammetry
    ( 2015-06-28) El Amin Mohamed Banaga, Ahmed ; El Shami Mohamed Masaad ; Surveying Engineering
    In the process of map compilation using stereo-plotting machines، ground control is needed. Each stereo-model requires at least 3 horizontal and 4 vertical ground control points. The establishment of such control by ground survey methods is time consuming and costly. Analytical aerial triangulation techniques based on the collinearity condition equations can be used for providing sufficient ground control from sparsely distributed، ground-surveyed control network. In this research work collinearity condition equations have been used for extracting three-dimensional ground coordinates from both close-range and aerial photographs. In these equations the two dimensional x، y photo coordinates were directly transformed into the three-dimensional X، Y، and Z object space coordinates. For camera calibration، the interior and exterior orientation parameters of the camera as well as differential scale factors along image axes are determined in the photogrammetric resection phase. Two computer programs were developed during period of this research project in FORTRAN language. The first program solves for ten parameters of inner and relative orientation for each photograph taken in a subsequent procedure (photo by photo). The three-dimensional ground coordinates were then obtained based on these parameters and the intersection procedure. The second program is based on bundle adjustment procedure. It solves for the ten parameters for each photo and .the ground coordinates in a simultaneous solution. . Two types of photo coordinates were used as data input in these programs. The first type of coordinates was obtained using a non-metric camera/comparator system. The second set of photo coordinates was obtained using the stereo-comparator of the A violyt BC2 analytical plotter owned by Sudan Armed Forces. The output of the two program solutions were compared with results obtained using the BC2 pre written software. Finally، contour maps generated from the derived ground coordinates by each of the two programs developed by the author were compared with maps obtained from the ground coordinates derived by the BC2 system.