This article throws light upon the six major problems in ranging and chaining of a line. Problem # 1. To erect, with a tape, a perpendicular to a chain line from a point on it: It can be done by forming a right angled triangle by taking three sides of a triangle in the proportion of 3, 4 and 5. [...]
The following are the five main methods of plotting a traverse survey: 1. By Parallel Meridians through Each Station 2. By Included Angles 3. By Central Meridian or Paper Protractor 4. By Rectangular Co-Ordinates 5. By Chords. Method # 1. By Parallel Meridians through Each Station: Having fixed suitably, the position of the starting point say A, draw a line [...]
The limit of length of the offset is below 15 and should not increase 15 m if its direction is set simply by eye or by tape. However, the length of offset mainly depends upon: (i) The scale of the plan (ii) The accuracy desired (iii) The maximum permissible error in eye judgement in laying out the direction of the [...]
The following two methods are generally adopted to find the areas from the previously plotted plans. The methods are: 1. Graphical Method. 2. Instrumental Method. 1. Graphical Method: In this method, the required data is obtained from measurements of the plan. The area may be found: (i) By the help of some geometrical figures or (ii) By the application of [...]
After reading this article you will learn about the construction and classification of scale of a map. Construction of Scales of a Map: In plotting a survey, often an object to be represented on paper is so large that it would be inconvenient to make a full sized drawing of it. The drawing or map is then made to a [...]
The three main obstacles in chaining of a line are of the following types: 1. Chaining Free, Vision Obstructed 2. Chaining Obstructed, Vision Free 3. Chaining and Vision Both Obstructed. It sometimes happens that a survey line passes through some object such as a pond, a building, a river, a hedge etc. which prevents the direct measurement of that part [...]
The setting up of the plane table includes three operations viz: 1. Levelling 2. Orientation 3. Centering. Operation # 1. Levelling: Place the table over the station-point and spread out legs to make it level and at a convenient height, preferably not above the elbow. Then oriented and centre the table approximately as explained in the following two operations and [...]
There are two main types of the field-book: 1. Single Line Field-Book 2. Double line Field-Book. The field measurements, sketches and relevant notes are recorded for future reference in a note book, known as field-book. The field-book in general use is about 20cm * 12cm and opens length wise. Type # 1. Single Line Field-Book (Fig. 3.18, b): Every page [...]
After reading this article you will learn about: 1. Meaning of Plane Table Surveying 2. Advantages of Plane Table Surveying 3. Disadvantages 4. Equipment Needed 5. General Instructions 6. Errors 7. Testing and Adjusting. Contents: Meaning of Plane Table Surveying Advantages of Plane Table Surveying Disadvantages of Plane Table Surveying Equipment Needed in Plane Table Surveying General Instructions while Plane [...]
Plotting means to represent on paper, to a suitable scale, the previously surveyed objects in accordance with their shape and size. Plotting is commenced after the field-work is over. The plotting of a chain survey is done in the following steps: (i) A suitable scale is chosen before starting the plotting work. The scale depends upon the importance of the [...]