Temperature study: These are a type of contour lines that connects points in a map with equal temperatures is called as an isotherm and those connecting areas with equal solar radiation is called as isohel. Cliffs are also shown by contour lines very close together and, in few occurrences, touching each other or very closely placed. In this case last line sometimes has tick marks pointing toward low ground. If you find a very steep slope in a map, you will notice that the contour lines converge into one “carrying” contour of contours. terrains of a location can be mapped as a plan view while the air or noise pollution in the area can be represented as a profile view. The profile view is often a parameter that is mapped vertically. Plan view allows the representation of the map in a way an observer would see it from above. These can be drawn as plan view or as a profile view. Types and Applications of contour linesĬontour lines have been used extensively in maps and representation of graphical and statistical data. The term “isoclines” refers to a contour line that joins points with equal slope. The terms “isogon”, “isoline” and “isarithm” are commonly used to describe contour lines. In 1889 Francis Galton proposed the term “isogram” as a reference for lines indicating equality or similarity in qualitative or quantitative features. Since then there has been a widespread use of contour lines for mapping and other applications. This method was used in 1791 by J.L Dupain-Treil for a map of France and in 1801 Haxo used it for his projects in Rocca d’Aufo. Thereafter the use of contour lines for cartography became a standard method. The concept of contour lines was used in surveying the mountainside for the experiment. In 1774 conducted the Schiehallion experiment to measure the mean density of the Earth. In 1746 contour lines were used to map land surface by Domenico Vandelli who drew a map of the Duchy of Modena and Reggio. Nicholas Cruquius used isobaths at an equal interval of 1 fathom to draw the bed of the river Merwede in the year 1727, while Philippe Buache used an interval of 10 fathoms for the English Channel in the year 1737. Throughout the 1700s contour lines have been used in numerous charts and maps to illustrate depths and heights of water bodies and landscapes.Įdmond Halley in 1701 used contour lines on a chart of magnetic variation. Contour lines denoting constant depth are now known as “isobaths”. The first recorded use of contour lines were made to illustrate the depth of the river Spaarne located near Haarlem by a Dutchman named Pieter Bruinsz in the year 1584. The use of lines joining points of equal value has been existent since a long time although they were known by names other than contour lines. Equally spaces and evenly spaced lines, it indicates uniform slope. Although the term contour line is commonly used, specific names are often used in meteorology where there is a greater possibility of viewing maps with different variables at a given time. The prefix “iso” can be replaced with “isoallo” which specifies that the contour line joins points where a given variable change at the same rate over a given period of time. Contour lines are often typified with the prefix “iso” which means “equal’ in Greek, as per the type of variable being mapped.
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