Explanation: There are 2 methods of contouring: direct and indirect. In direct method, the points of elevation are located physically and then plotted on the map. Indirect method uses contouring with the help of grids.
What is the method of direct contouring?
Detailed Solution. In the direct method, the contour to be plotted is actually traced on the ground. Points which happen to fall on the desired contour are only surveyed, plotted and finally joined to obtain the particular contour.
What method of contour is suitable for contouring in hilly areas?
Cross Section method This method is generally used for hilly terrain to produce contour lines.
What are the indirect methods of contouring?
These methods are commonly employed in small scale surveys of large areas or during mapping of irregular surface or steep slope. There are two different ways usually employed for indirect method of contouring: Grid method and. Radial line method.Which method of contouring is more time consuming?
In direct method, the points of equal elevation on the terrain are physically located and then plotted on map. This is a very tedious process and requires more time and resources than the indirect method.
How many types of EDM are there based on reflector type?
How many types of EDM are there based on the reflector type? Explanation: The 3 types are active, passive and no reflector. In active type, power is required to operate reflectors.
What is grid contouring?
The art of determining relative altitudes of points on the surface of the earth of beneath the surface of earth is called LEVELLING. A contour is defined as an imaginary line of constant elevation on the ground surface. … This technique of making observations and plotting on a plan is called as grid leveling.
What is contouring in civil engineering?
Contouring in surveying is the determination of elevation of various points on the ground and fixing these points of same horizontal positions in the contour map.What are the types of contour lines?
Contour lines are of three different kinds. They are the Index lines, Intermediate lines and the Supplementary lines.
Which method is used to locate contours when the area to be surveyed is small and the ground is not much undulating?A) By Square method:- When the area to be surveyed is small and the ground is not very much undulating without any vegetative covers, this method is used for contouring.
Article first time published onWhich method should be used to determine the highly accurate contours in small area?
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.
Which method is used for the preparation of a contour plan for a route survey?
For preparation of a contour plan for a route survey. keyword ‘route survey’. hence cross sections at suitable intervals will be use. hence the answer is ‘method of cross profile is used’.
What are the different types of Levelling?
- Direct leveling.
- Trigonometric leveling.
- Barometric leveling.
- Stadia leveling.
What is the rise and fall method?
Introduction. The rise and fall method is the method of calculating the difference in elevation between consecutive points in levelling work. Some of the points you have to know before starting numerical are: Back sights: The first reading after seeing the instrument is called back sights.
What is contour PDF?
•Contour An imaginary line on the ground surface joining the points of equal elevation is known as contour. •It facilitates depiction of the relief of terrain in a two dimensional plan or map.
What is block contouring?
By squares (block contouring)- In this method the area to be surveyed is dividing into no of the square of size 5 to 20m. depending upon the nature of ground and contour interval required. The elevation of the corner of the square is determined by the mean of the process of levelling.
When contours of different elevations cross each other?
Vertical cliff: Contour lines of different elevations unite to form one line. Overhanging cliff: Two contours of different elevation cross each other in this case.
What is the range of medium range EDM *?
Short-range, electro-optical instruments using amplitude-modulated infra-red or visible light with ranges up to 5 km. Medium-range microwave equipment, frequency modulated to give ranges around 25 km. Long-range radio wave equipment with ranges up to 100 km.
For what purpose is Distomat used?
The Distomat is a very small, compact electronic distance measurement device, particularly useful in construction and engineering works. The Distomat measures distances smaller than 500 meters by simply pointing the instrument to a reflector and reading the result.
What are the different types of slopes in geography?
- Gentle: Contour lines showing a uniform, gentle slope will be evenly spaced and wide apart. …
- Steep: Contour lines showing a uniform, steep slope on a map will be evenly spaced, but close together.
What are the different characteristics of contour lines?
- Must close on themselves, on or off the map.
- Perpendicular to the direction of max. …
- Slope between them is assumed uniform.
- The distance between them indicates the steepness of the slope, gentle or steep.
- Irregular signify rough, smooth signify gradual slopes.
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 is contour interpolation and its method?
Interpolation of the contours is the process of spacing the contours proportionately between the plotted ground points established by indirect methods. The methods of interpolation are based on the assumption that the slope of ground between the two points is uniform.
What is the purpose of contouring explain its various methods in detail?
Contouring is an important aspect of surveying which basically involves the determination of the elevation of various points on the ground followed by fixing the points of the same horizontal positions in the contour map. A contour may be defined as an imaginary line that passes through the points of equal elevation.
Which of the following is an indirect method of survey?
Among indirect methods are surveys, exit interviews, focus groups, and the use of external reviewers.
What is combination of Total Station?
A total station is a combination of an electronic theodolite, an electronic distance measuring device (EDM) and a microprocessor with memory unit. The electronic digital theodolite, first introduced in the late 1960s by Carl Zeiss Inc., helped to set the stage for modem field data collection and processing.
Which of the following are used in chain survey to measure the short offset?
With the help of the chain, the outline of the survey lines is measured. The metallic tape and the cloth are used for the measuring purpose of the short offset that can provide accuracy with zero error.
What is Traverse method?
Traverse is a method in the field of surveying to establish control networks. It is also used in geodesy. Traverse networks involve placing survey stations along a line or path of travel, and then using the previously surveyed points as a base for observing the next point.
What is leveling methods in surveying?
Surveying and Leveling Levelling is a process of determining the height of one level relative to another. It is used in surveying to establish the elevation of a point relative to a datum, or to establish a point at a given elevation relative to a datum.
How many different leveling instruments are there?
There are mainly two types of telescope, (1) the external focusing telescope, and (2) the internal focusing telescope. Most of the modern levelling instruments are designed with internal focusing telescope. The level tube is used for the temporary adjustment of the instrument.
