Khaled Mohamed Zaky

• Associate Professor of Surveying
• Benha University

Whilst there are many factors posing hurdles in an accurate geoid model determination, only the effect of variable topographic mass density to the geoid undulation is of concern in this paper. Thus, the surface computed by Stokes formula from topographic-isostatics gravity anomalies is not the geoid itself but a slightly different, for every gravit...

Systematic, random and gross errors are considered the main problems facing those working in the photo-triangulation processes. The influence of systematic errors on photo-measurements may include lens distortion, film deformation, refraction and other distortions. Usually, these types of errors can be solved by the calibration process. Meanwhile,...

The aim of this research is to tailor the Experimental Gravity Field Model [XGM2016] harmonic model to Egypt for better modeling of the Egyptian gravity field. This can be made by computing the differences between local gravity anomalies and those derived from the geopotential model, then the harmonic analysis of the residual gravity anomalies yiel...

Digital Elevation Model (DEM) is imperative to the creation of slope maps, the substructure planning, gravity field modeling and many other applications. Thus, there is a great need for accurate and low cost DEMs. In this case study, Shuttle Radar Topography Mission (SRTM) 30m, SRTM 90m have been used with Topographic DEM generated from ground topo...

The main aim of this research is to investigate the impact of vertical accuracy of digital elevation models (DEMs) on the orthoimage production process. The study took place on a QuickBird image by using four different DEMs with different vertical accuracies, nine ground control points (GCPs), and three sensor models. The four DEMs are global posit...

There is different robust estimation methods used for detecting small gross errors which may be presence in geodetic observations. Some of these methods are robust M-estimators, Least Absolute Sum and Danish method. The conventional Least Squares Estimation method and these robust estimation methods have been tested and applied on a precise geodeti...

New additional Global Geopotential Models [GGMs] have now been released into the public domain, those including data from the CHAMP, GREACE and GOCE dedicated satellite gravimetric mission. Those satellite tracking data have resolved the long wave length component of the global gravity field with rather very high accuracy [10].Therefore, it is impo...

A solution for the problem of determining the Geodetic Latitude on the ellipsoidal earth, in terms of the Map (Isometric) or Mercator Latitude is presented in this research. The proposed model relies mainly on the spherical case by contributing a residue function which anticipates the disparity between spherical and ellipsoidal cases. The residue f...

This study presents a method to explore a new procedure for building outer boundary extraction from high resolution satellite imagery such as IKONOS. The procedure proposed for building extraction involves the use of supervised classification technique to the test area to segment the building classes from the background and any other classes. The i...

Digital mapping technology is considered the most important source of information for many concerning organizations. There are several cartographic problems until now facing the cartographers during the execution of different processes. Some of these problems appear during the preparation of the digital data. That is because the format of digital d...

Most of the surveying instruments have changed with the rapid change of technology. One of these instruments is the level. Some leveling works require to be executed in a short time with a high level of accuracy. Also, costs require to be as less as possible. Example of these works is the establishment of bench marks. A part from a road of 2 km len...

The representation of the third dimension (elevation) i.e. relief representation considered as an important problem facing the cartographers. This problem have to be solved. The main objective of this paper was to show the cartographic treatment of topographical relief using CAD systems (Computer Assisted Drawing). AutoCAD software package of versi...

There are many problems have been arisen in Mokattam since 1955 up till now. These problems appeared clearly in the retreat of the edge of upper Mokattam plateau, damage of Cornich street and some constructions there. For this, a strong recommendations are proposed to observe these problems to know the reasons of these occurrences which may be rela...