Journal of Surveying Engineering

Georeferencing aerial photographs has always been a challenge. Computer technology makes it possible to georeference digital aerial photographs without an in-depth understanding of the underlying theory. For students of remote sensing, hands-on manual georeferencing is essential to fully understand the theories and the nature of errors in aerial photography. This paper provides a manual procedure to convert aerial photographs into an orthophoto-like product.

The aim of this study is to improve functional models and to form a new stochastic model that takes into account both different measurement methods and important sources of errors affecting the accuracy of the measurements in a combined leveling net measured by different instruments and measurement methods. In this study, three functional models are explained. In addition, four well-known stochastic models and a new stochastic model are presented. Two types of unknowns are used in the least-squares adjustment of functional models. One of them is the scale factor, and the other is the parameter of refraction and deviation of the plumb line. Four criteria are explained to examine the functional old and new stochastic models. The first criterion is whether or not the adjustment gives reasonable results. The other criteria are the functional model test, stochastic model test, homogeneity, and mean accuracy test. To achieve the objectives stated earlier, a leveling net located in and around Istanbul, Turkey, is used, consisting of 81 benchmarks and 76 lines. Five lines are measured using both reciprocal trigonometric leveling and valley crossing leveling. The rest are measured by the precise leveling method. The net is adjusted using the free adjustment approach along with stochastic models, which are known and suggested.

This paper introduces the ISO 9000:2000 Standards and the role of engineering surveyors under the quality assurance and management standards of the construction industry.

A procedure is discussed that combines the best aspects of the usual “rigid body” (three parameter affine) and the similarity (Helmert) least-squares procedures found in most civil engineering enhancements to popular computer-aided design programs. The procedure will work to transform North American Datum of 1927 coordinates into the North American Datum of 1983 (NAD83) system, and will work in transforming arbitrary coordinates (coordinates derived in an arbitrary system) to NAD83. In all of these transformations, coordinates of a number of points are required in both systems, and provide the basis for the transformation.