Table of Contents
How are contour maps made?
The two ways to establish a contour map are the cross-section method and the trace contour method. To use the cross-section method, set a control or reference line at the center of the lot, then lay out and stake a grid; the elevation is determined at each stake in the grid relative to a benchmark.
What is a contour map science?
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 is a contour map made of and what does it show?
Elevation contours are imaginary lines connecting points having the same elevation on the surface of the land above or below a reference surface, which is usually mean sea level. Contours make it possible to show the height and shape of mountains, the depths of the ocean bottom, and the steepness of slopes.
How are elevation maps created?
Horizontal control points are surveyed to determine the longitude and latitude, while vertical control points are surveyed separately to determine elevations. The location and elevation of these control points help the map makers correctly position the aerial photo images and assign values to the contour lines.
How do you make your own contour?
Note: For 3D Analyst, navigate to System Toolboxes > 3D Analyst Tools > Raster Surface > Contours.
- Select the output from Step 1 as the input raster.
- Specify the name and location of the output polyline features.
- Set the contour interval value.
- Click OK.
What do each of the contour lines on a topographic map represent?
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.
Why do we contour maps?
Earth’s surface has many different kinds of landforms that vary widely in height and elevation. Contour maps show the elevations of these surface features, which allows you to look at a two-dimensional map to visualize the Earth in three dimensions.
Who draws topographic maps?
A pair of aerial photographs–each showing the same ground area taken from a different position along the flight line–are viewed through an instrument called a stereoscope, producing a three-dimensional view of the terrain from which a cartographer can draw a topographic map.
What are contour maps use to identify?
Contour maps are extremely useful for various engineering works: Civil engineer studies the contours and finds out the nature of the ground to identify. Suitable site for the project works to be taken up. By drawing the section in the plan, it is possible to find out profile of the ground along that line. Intervisibility of any two points can be found by drawing profile of the ground along that line.
What do the lines on a contour map tell us?
Index lines are the thickest contour lines and are usually labeled with a number at one point along the line. This tells you the elevation above sea level. Intermediate lines are the thinner, more common, lines between the index lines. They usually don’t have a number label. Supplementary lines appear as dotted lines, indicating flatter terrain.
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 maps indicate?
A contour map, sometimes called a topographic map, is a representation of a three-dimensional feature using contour lines on a flat surface. The map shows a bird’s-eye view and allows people to visualize the hills, valleys, and slopes that are being mapped.