What is Contour Interval?

What is Contour Interval?

A contour interval in surveying is the vertical distance or the difference in the elevation between the two contour lines in a topographical map. Usually there are different contour intervals for the different maps. Considering the size of the area to be mapped, contour intervals are assumed. In every map, on the right-hand bottom side, the contour interval is specified. When the contour interval is not specified in the map, it can be calculated as explained in the following sections. The commonly used contour interval is 20 feet for a 1:24,000 map scale.

Methods of Contour Interval

There are one-of-a-kind techniques of figuring out contour c programming language on a map. Some of the not unusualplace techniques are:

Direct size: This includes measuring the space among contour strains and dividing it through the range of contour periods among them. For example, if the space among  contour strains is 200 ft and there are 4 contour strains in among, then the contour c programming language could be 50 ft (2 hundred/4).

Using a formulation: The contour c programming language may be calculated the use of a formulation that takes under consideration the dimensions of the map and the vertical distance among  contour strains. The formulation is: contour  = vertical distance / (map scale x contour aspect). The contour aspect is a number of that relies upon at the gadgets of size used at the map.

Using software program: Many mapping software program applications have gear which can robotically calculate contour periods primarily based totally at the elevation statistics of the place being mapped.

Uses of Contour Intervals

Contour periods are used for numerous purposes, including:

  • Mapping topography: Contour strains are used to map the form and elevation of the terrain.
  • Engineering: Engineers use contour strains to layout infrastructure which include roads, bridges, and buildings.
  • Environmental planning: Contour maps are used to decide the fine places for natural world habitats, parks, and leisure areas.
  • Agriculture: Contour maps are utilized in agriculture to plot irrigation systems, and to map soil sorts and erosion patterns.
  • Geology: Contour maps are utilized in geology to map the distribution of rocks, minerals, and geological features.
  • Navigation: Contour maps are utilized by hikers and mountaineers to plot routes, and through pilots to navigate via mountainous areas.

Contour Intervals Calculation

Usually, the map legend identifies the contour spacing at the map, however every now and then handiest a part of the map is to be had. Knowing a way to calculate contour c programming language turns into a beneficial technique. On maximum maps, every 5th contour, marked with a thicker or darker line, is an index line or an index contour. This index line is marked highly. Find the elevation of the 2 adjoining index strains. The maximum range represents an uphill ascent. Find the distinction among the 2 elevations.

How To Read Contour Line?

The Contour Lines suggest the form of the earth. A unmarried contour line denotes an identical elevation line, which suggests that if the contour line computes an elevation of a thousand ft above common sea level, each factor alongside that line is a thousand ft above common sea level. The contour strains by no means cross, as a factor at the map can not own  one-of-a-kind heights at a comparable time. The farther the contour strains arrive at the map, the smoother the slope of the earth is. The close to the contour strains arrive, the extra willing the terrain will be.

Reading the contour strains Where the contour strains get extraordinarily close, an nearly precipice happens. If the relaxation is a vertical cliff, the contour strains almost come collectively and may look as though they're merging. Pending cliffs will have one line crossing over the extra (that is the simply time the ones strains can cross), with the only line performing as dotted.

Factors Affecting The Selection Of Interval

The survey chief has to outline the choice of the c programming language earlier than the beginning  of the mapping manner primarily based totally on floor elements as follows,

1. Scale Of The Maps

The c programming language is retained inversely proportional to the dimensions of the map. Less the dimensions of the map, the bigger the c programming language. On the alternative side, if the dimensions of the map is massive, the c programming language need to be small. If on a small-scale map, a small contour c programming language is received the horizontal distance among  consecutive contours.

2. Purpose Of The Map

The c programming language on a map additionally is based at the goal for which the map is to be used. If the map is ready for commencing a motorway on hills slopes, a massive c programming language is probably enough.

3. Nature Of The Ground

The contour c programming language is based on the overall topography of the terrain. In the flat floor, contours at small periods are monitored to explain the overall slope of the floor while excessive hills can without a doubt be illustrated with contours at large periods.

4. Availability Of Time And Funds

If the time to be had is limited, a more c programming language is received to complete the mission in a selected time. On the alternative hand, if good enough time is on the disposal, a smaller c programming language is probably determined, preserving in view all of the various factors already described.

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