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| Articles
by
E.M. Elhadi |
Total Records (
3 ) for
E.M. Elhadi |
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E.M. Elhadi
,
Hu .Guangdao
and
N. Zomrawi
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Pixel resolution is one of the main factors that affecting the final result in digital photogrammetry in general and in digital photogrammetric workstation in particular. An aerial wide-angle hard copy stereo pair was transformed to a soft copy using different scanning resolution by special photogrammetric scanner. Digital photogrammetric workstation was used to measure a number of control points of a known ground coordinates. ERDAS package was used to digitally rectify the scanned images using the same pixel resolution used above. And the coordinates of points were measured again. The results of this investigations proof that the accuracy of the measurements in digital photogrammetry is proportional to scanning pixel resolution in both horizontal and vertical measurements. And mathematical models were developed to estimate the accuracy via scanning resolution and suitable plotting scale in both horizontal and vertical mapping. Production of maps using digital image rectification using software packages such as ERDAS is suitable only in flat terrain. And digital photogrammetric workstation is a productive way for mapping in all flat and mountainous terrain. |
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E.M. Elhadi
,
Hu. Guangdao
and
O. Elkhider
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One of the most commonly used methods for positioning afloat is by measuring ranges from shore stations to the point a float. This technique is widely used on offshore industry (rig placement, pipe lines...etc). The deployment of the shore stations is largely dependent on the configuration of the coastline. The hydrographer finds it is difficult to deploy the desired number of points on the coastline without compromising the factors of strong geometric fix and land path problems. In order to avoid such problems, the acoustic positioning system using satellites and transponders is nowadays used frequently for all offshore engineering projects. In this study, an attempt to determine the optimum range observations to a float point, which could satisfy requirement of coast configuration and meet the accuracy specified. |
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E.M. Elhadi
,
Hu. Guangdao
and
N. Zomrawi
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Collinearity condition equations are one of the most fundamental equations in analytical and digital photogrammetry. They have different forms and applications in photogrammetry, such as the computation of internal and external orientation parameters of the photograph and computation of ground coordinates of points that can be identified the successive overlapping photos. This study discusses the results of applying two terms of collinearity condition equations, one consists of 6-terms and the other consists of 10-terms on a photo a stereo-pair, consists of 20 control points, acquired by an aerial camera. It was found to be that for the metric camera the two algorithms relatively produces the same precision. Therefore, in aerial photogrammetry, it is sufficiently enough to use the model of 6-terms collinearity condition equations for topographic mapping. This will certainly reduce the cost of establishing more ground control points. |
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