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Petroleum Geological Survey
Published in Muhammad Abdul Quddus, Petroleum Science and Technology, 2021
A contour line joins all the points of subsurface strata height/elevation of equal value on the map. The base level contour line on the map is sea level. A numbers of contour lines are drawn on the map, each line showing a particular height. Any point on the contour line is above sea level. The difference in elevation between two adjacent contour lines is called the ‘contour interval’. After every five contour lines, a line is selected and designated as the ‘index contour’. The index contour is marked by a bold (darker) line. These facilitate reading and quick identification of elevation at any point. Elevation changes more rapidly on an inclined surface than on the nearly flat or less sloped surface. In a very steep slope structure, the contour lines are closely packed and their contour intervals are small. In a less sloped object, the contour intervals are large. The shapes of contour represent the object, such as a hill or valley or plain. A slope covers both an elevation and depression in the broader sense. A vertical erected wall side has a maximum slope of 90° and maximum inclination, represented by single contour line and a flat surface has a minimum slope of 0° and minimum inclination; 45° indicates middle inclination. The shape and the number of contour lines drawn in the map gives the details of the selected area.
The Content of the Site Plan
Published in Robert M. Sanford, Environmental Site Plans and Development Review, 2017
Contour lines denote lines of elevation on a map. The lines are the result of connecting a series of points of equal elevation above Mean Sea Level in either feet or meters. The interval between contours is given on the map. The spacing between the lines indicates the topography. Several contour lines drawn close together indicate steep slopes. Contour lines that are far apart show a gentle slope or relatively flat land. Usually, every fourth or fifth contour is an index contour drawn as a slightly wider line to help in counting contours. If the contour map seems complex and it is hard to visualize the site, it may help to combine and color the contours on your map by group. For example, all elevations over 400 feet could be a dark color and the colors could gradually lighten for groups of lower elevation contours.
Vertical control
Published in W. Schofield, M. Breach, Engineering Surveying, 2007
A contour is a horizontal curve connecting points of equal elevation. Contours graphically represent, in a two-dimensional format on a plan or map, the shape or morphology of the terrain. The vertical distance between contour lines is called the contour interval. Depending on the accuracy required, they may be plotted at 0.1 m to 0.5 m intervals in flat terrain and at 1 m to 10 m intervals in undulating terrain. The interval chosen depends on: The type of project involved; for instance, contouring an airstrip requires an extremely small contour interval.The type of terrain, flat or undulating.The cost, for the smaller the interval the greater the amount of field data required, resulting in greater expense.
Damage detection in beam through change in measured frequency and undamaged curvature mode shape
Published in Inverse Problems in Science and Engineering, 2019
Mustapha Dahak, Noureddine Touat, Mounir Kharoubi
The purpose of this work is to present a method for predicting the damage location and severity, based on the frequency contour method. Unlike the methods presented in the literature as in [64–75], the one presented in this work does not require neither the solving of the governing differential equation analytically to obtain the contour line, nor the numerical calculation of the frequencies by varying all damage severities and locations. In other words, the detection method does not require the modelling of the damage. The contour lines are plotted using the value of the changes in the measured natural frequencies and the vectors of the curvature mode shapes of the intact structure, which can be calculated numerically or can be derived from the measured mode shapes. The intersection of the plotted curves gives the damage location and coefficient (ζ) (which stays for the damage severity). Then, a relationship between the damage depth and the coefficient (ζ) has been designed to predict the damage severity. In order to verify the robustness and the practical applicability of the developed theoretical method, a numerical simulation and an experimental framework on cantilever beam have been designed. The results confirm the applicability of the developed method in real applications.