What is major and minor contour lines?
The major contour lines at the decades are logarithmic values that are equally spaced, and the minor contour lines are linear values that are logarithmically spaced.
What do the symbols on a topographic map mean?
The distinctive character- istic of a topographic map is that the shape of the Earth’s surface is shown by contour lines. These symbols are con- stantly refined to better relate to the features they represent, improve the appearance or readability of the map, or reduce production cost.
What are Hachure lines?
Hachures are short lines laid down in a pattern to indicate direction of slope. When it became feasible to map rough terrain in more detail, hachuring developed into an artistic speciality.…
What is a contour interval example?
For example, a topographical map of an area near Denver might have index contours of 5,000′, 5,100′ and so on with a contour interval of 20 feet. This means that there would be five “spaces,” and four non-index contour lines, between each index contour. Often, index points are given along with index contours.
What is an example of elevation?
Elevation is defined as the height above the ground or other surface, or a place or position of height. An example of elevation is a plane flying at 36,000 feet above the ground. An example of elevation is a ballet dancer leaping three feet in the air.
What is elevation explain its importance?
An elevation is a rise or the raising of something. Mountains have an elevation based on how high they are and your mood has an elevation as you get happier. Elevation is a noun that tells how high something is raised above a surface or ground line. It’s also a term for measuring things like temperatures or degrees.
Why do contour lines never cross on a topographic map?
Contour lines can never cross one another. Each line represents a separate elevation, and you can’t have two different elevations at the same point. The closer contour lines are to one another, the steeper the slope is in the real world.
What is used to measure elevation?
What is the meaning of elevation?
1 : the height to which something is elevated: such as. a : the angular distance of something (such as a celestial object) above the horizon. b : the degree to which a gun is aimed above the horizon. c : the height above the level of the sea : altitude..
How do you read elevation?
To find an elevation, simply set the rod foot at any location on the job within the range of your laser or optical instrument. Run the detector and / or front rod section up or down until you pick up the “on grade” signal from your detector. Read the number opposite the pointer. That number is your true elevation.
What are the factors on which contour lines are based?
The contour interval depends upon the general topography of the terrain. In flat ground, contours at small intervals are surveyed to depict the general slope of the ground whereas high hills can only be depicted with contours at larger contour interval.
What is meant by 1 50000 on a topographical sheet?
REPRESENTATIVE FRACTION (RF): It is the ratio between the distances on the map to its corresponding distance on actual ground. The RF on this map is 1:50,000.
What are the 5 major terrain features?
The five major terrain features are: Hill, Ridge, Valley, Saddle, and Depression. The three minor terrain features are: Draw, Spur and Cliff. The two supplementary terrain features are: Cut and Fill.
What is meant by contour interval?
A contour interval is the vertical distance or difference in elevation between contour lines. Index contours are bold or thicker lines that appear at every fifth contour line. If the numbers associated with specific contour lines are increasing, the elevation of the terrain is also increasing.
What is the space between contour lines called?
The space between the contour lines is called the contour interval and represents a specific (set) distance. If the contour interval is 50 feet, the vertical space between the two contour lines is 50 feet.
What are the uses of contouring?
Uses of the Contour Lines
- To estimate the water storage capacity, back water limit and max .
- Volume of the proposed excavation wok,
- To decide whether certain location is visible from another location,
- To decide exact line of railway or road way haing safe slope,
- To determine the ground water level from contours of ground water.
What is the importance of an elevation of a point?
Probably their most important function is to reveal the topography, that is, the shape of the land. Topography is shown by contours, lines composed of points with the same elevation. Elevation refers to the vertical height of a point above sea level.
How do you calculate contour lines?
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.
How do you find the elevation of a contour line?
You can figure out the elevation of any point by finding the nearest labeled line, counting the number of lines above or below it, multiplying by the contour interval, and adding or subtracting the result from the nearest marked contour line. The more closely spaced the contour lines, the steeper the slope.
How do you find the elevation between two points?
To calculate percent slope, divide the difference between the elevations of two points by the distance between them, then multiply the quotient by 100. The difference in elevation between points is called the rise. The distance between the points is called the run.
How do you accurately measure elevation?
The most important altitude measurement tool in your phone’s arsenal is the GNSS/GPS receiver. If your phone can find at least four satellites, with one directly overhead, you can usually get an altitude reading accurate to within 10 to 20 meters (35 to 70 feet).
What is difference between a contour interval and horizontal equivalent?
Contour interval (CI) is the difference of value of two consecutive contours (larger contour value – next smaller contour value). Horizontal equivalent is the horizontal distance between any two consecutive contours. Generally CI remains constant for any contour map, but horizontal equivalent varies with varying slope.
What 2 types of lines show elevation differences?
Contour lines are used to show elevation on a topographic map. Lines or isolines on a map that connect points with the same elevation. What does each contour line on a map show? Each contour line shows a different elevation.