What do the numbers on contour lines mean?
Contour line, a line on a map representing an imaginary line on the land surface, all points of which are at the same elevation above a datum plane, usually mean sea level. Numbers on the lines give the height in feet. (Sea level is zero.) Lines drawn closely together indicate that a slope is steep.
What are the 5 Rules of contour lines?
Rule 1 – every point of a contour line has the same elevation. Rule 2 – contour lines separate uphill from downhill. Rule 3 – contour lines do not touch or cross each other except at a cliff. Rule 4 – every 5th contour line is darker in color.
What are the 3 contour lines on a map?
Contour lines are of three different kinds. They are the Index lines, Intermediate lines and the Supplementary lines.
What do numbers on a topographic map mean?
Horizontal distance is found on the scale. As you look at the map, notice that the contour lines enclose smaller and smaller areas. The smallest circles represent the tops of peaks, and some are marked with x’s with numbers next to them. The numbers are the elevation at the top of the peak.
How are contour lines measured?
Lighter contour lines do not have elevations, but can be determined by counting up or down from the nearest index contour line and multiplying by the contour interval. The contour interval is stated on every topographic map and is usually located below the scale.
What is the elevation between contour lines?
The elevation difference between two adjacent contour lines is called the contour interval (CI). Usually the contour interval is noted on the map legend. In most topographic maps every 5th contour line is drawn in bold print or wider than other contours.
How do you calculate contour lines?
What Is the Contour Interval Equal To? Divide the difference in elevation between the index lines by the number of contour lines from one index line to the next. In the example above, the distance 200 is divided by the number of lines, 5. The contour interval is equal to 200 / 5 = 40, or 40-unit contour intervals.
What do contour lines represent on a topographic map?
A topographic map illustrates the topography, or the shape of the land, at the surface of the Earth. The topography is represented by contour lines, which are imaginary lines. Every point on a particular contour line is at the same elevation. These lines are generally relative to mean sea level.
What is contour on a map?
In cartography, a contour line (often just called a “contour”) joins points of equal elevation (height) above a given level, such as mean sea level. A contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.
What are the different types of contour lines on a map?
Isopleth. Isopleth on a contour map connects the places having the same value of some measurable quantity of geographical or meteorological phenomena.
What do contour lines represent on a map?
Put simply, contour lines mark points of equal elevation on a map. If you trace the length of a line with your finger, each point you touch is the same height above sea level. If you were to walk the path of a contour line in real life, you would remain at the same elevation the whole hike, never traveling up or down.
What can we tell from contour lines?
Contour lines are lines drawn on a map connecting points of equal elevation, meaning if you physically followed a contour line, elevation would remain constant. Contour lines show elevation and the shape of the terrain. They’re useful because they illustrate the shape of the land surface — its topography– on the map.
What do the contour lines on the map represent?
Basics of Contour Lines in Topographical Maps 3-D Surface. A topographical survey of contour lines aims to represent a 3-dimensional image that uses only two actual dimensions, such as a piece of paper. Gentle Slope Contour. Contour lines will appear further and further apart for gentle slopes or even wholly flat surfaces on your property. Steep Slope Contour. Hill Contour.