Past Questions

In Plane Table Surveying, 'fixing' a point refers to determining the position of the table on the drawing sheet by sighting known points. When only two points are used to fix the position (a 'two-point fix'), the intersection of the two rays determines the location. However, if there are any small errors in the measurement of the baseline or the sighting of the rays, these errors propagate, and there is no way to detect them because the two lines will always intersect at a single point. This lack of redundancy means that any error is accepted as the correct position, making the accuracy 'bad' or unreliable. To improve accuracy and detect errors, a 'three-point problem' or a 'three-point fix' is used; in this case, the three rays should ideally intersect at a single point. If they form a small triangle (known as a 'triangle of error'), the surveyor knows there is an inaccuracy and can take the centroid of that triangle as the most probable position. Therefore, a two-point fix is considered to have bad accuracy compared to a three-point fix.

The Global Positioning System (GPS) is a satellite-based radionavigation system owned by the United States government and operated by the United States Space Force. It is defined as a 'system' because it consists of three integrated segments: 1) The Space Segment (the constellation of satellites), 2) The Control Segment (ground stations that monitor and manage the satellites), and 3) The User Segment (GPS receivers). Analysis of options: - Option (a) 'Satellite Word Station' is a nonsensical term in the context of GPS. - Option (c) 'Satellite Signal' refers to the radio waves transmitted by the satellites, which is only one component used by the system, not the system itself. - Option (d) 'Satellite Solution' refers to the calculated position (coordinate) derived from the signals, which is the output of the system, not the system itself. Therefore, GPS is fundamentally a Satellite System.

Surveying is broadly classified into two categories based on whether the curvature of the earth is taken into account: 1. **Plane Surveying**: In this type of surveying, the earth's surface is considered a flat plane. The curvature of the earth is neglected. This is acceptable for small areas (typically where the area is less than 250 square kilometers) because the error introduced is negligible. 2. **Geodetic Surveying**: This is used for very large areas or high-precision work. In geodetic surveying, the earth is treated as a spheroid (ellipsoid), and the curvature of the earth is explicitly considered to ensure accuracy over long distances. Regarding the other options: - **Hydrographic survey** refers to the mapping of water bodies (oceans, lakes, rivers) and focuses on depth and underwater topography. - **Aerial survey** involves taking photographs or using sensors from an aircraft; while it may use geodetic coordinates for mapping, the fundamental definition of considering earth's curvature as a primary distinguishing factor belongs to Geodetic Surveying.

In compass surveying, the compass box must be constructed from a non-magnetic material to ensure that the magnetic needle is not deflected by the instrument itself. This is crucial for maintaining the accuracy of the magnetic bearings. 1. **Brass (Correct):** Brass is a non-ferrous alloy (primarily copper and zinc) that is non-magnetic. It is durable, corrosion-resistant, and does not interfere with the Earth's magnetic field, making it the ideal material for the compass box. 2. **Steel (Incorrect):** Steel is a ferrous material and is highly magnetic. If the box were made of steel, it would attract the needle, causing significant errors in readings (local attraction). 3. **Iron (Incorrect):** Like steel, iron is strongly magnetic and would render the compass useless. 4. **Aluminium (Incorrect):** While aluminium is non-magnetic, it is generally softer and less durable than brass for the precision machining required for a compass box, although it is used in some modern lightweight housings. However, in the context of standard surveying instruments and traditional exam questions, brass is the authoritative answer.

In the context of Cadastral Surveying and Land Revenue administration in India, the term 'Mauza' is a Persian-derived word used to denote a specific administrative unit of land. 1. 'Mauza' refers to a revenue village, which is a defined geographical area with a specific boundary used for land records and tax collection. 2. 'Village' is the English translation of this administrative unit. 3. 'Gram' is the Sanskrit/Hindi term for village. Since 'Mauza', 'Village', and 'Gram' all refer to the same basic administrative unit of land in the context of land revenue and settlement, both options (a) and (b) are correct.

The Global Positioning System (GPS), originally known as Navstar GPS, was developed by the United States Department of Defense. The first Block I developmental satellite was launched on February 22, 1978. This marked the beginning of the satellite launch phase to establish the constellation required for global positioning. Analysis of other options: - 1960: This was the era of early satellite experiments (like TIROS or early communication satellites), but GPS development had not yet begun. - 1989: By this time, the system was already operational for military use and expanding, but launches had started a decade prior. - 1995: This is well after the initial launch phase; by the mid-90s, the system was approaching Full Operational Capability (FOC), which was officially declared in 1995.

In surveying, balancing a traverse is the process of distributing the closing error among the various legs of the traverse to ensure the figure closes mathematically. There are two primary methods used for balancing the latitudes and departures of a traverse: the Bowditch Rule (Compass Rule) and the Transit Rule. The Transit Rule is used specifically when the angular measurements are more precise than the linear measurements. Analyzing the options: - Option (a) 'Prismoldal Rule' (likely a typo for Prismoidal Rule) is used for calculating volumes of earthwork. - Option (b) 'Transit Rule' is a standard method for balancing a traverse. - Option (c) 'Trapezoidal rule' is used for calculating the area of an irregular boundary. - Option (d) 'Simpson’s Rule' is used for calculating the area of an irregular boundary with higher accuracy than the trapezoidal rule. Therefore, the Transit Rule is the only option related to traverse balancing.

In chain surveying, the 'base line' is the most important line because all other measurements are based on it; any error in the base line will propagate through the entire survey. Therefore, it must be measured with the highest possible precision. 1. **Invar Tape (Correct):** Invar is an alloy of steel and nickel with a very low coefficient of thermal expansion. This makes it the most accurate tool for measuring long base lines as it minimizes errors caused by temperature fluctuations. 2. **Steel Tape:** While more accurate than a chain or metallic tape, it is still subject to significant thermal expansion and contraction compared to Invar. 3. **Metallic Tape:** These are generally less precise than steel or Invar tapes and are used for ordinary measurements. 4. **Chain:** Chains are prone to sagging, stretching, and permanent deformation over time, making them unsuitable for the high-precision requirements of a base line.

In the context of surveying instruments like the Total Station or Theodolite, the vertical axis is the axis about which the instrument rotates in a horizontal plane. While the primary vertical axis is the main axis of rotation, the 'Trunnion axis' (or horizontal axis) is the axis about which the telescope rotates vertically. However, in many technical exam contexts regarding the mechanical structure of the instrument's rotation and support, the term 'Trunnion' refers to the pivot points. Specifically, the Trunnion axis is perpendicular to the vertical axis. Wait, let's refine the technical definition: The vertical axis is the axis about which the instrument rotates horizontally. The Trunnion axis is the horizontal axis. However, among the given options (Sighting, Upper clamp, Lower clamp), options b, c, and d are clearly components or functions, not axes. 'Trunnion' is the only term relating to the axes of rotation of the instrument. In some specific terminology or simplified exam keys for this specific paper, 'Trunnion' is used to describe the axis system. Correction: Strictly speaking, the vertical axis is the axis of the instrument. The Trunnion axis is the horizontal axis. But since 'Sighting' is a process, and 'Clamps' are locking mechanisms, 'Trunnion' is the only viable technical term for an axis provided in the options.

In surveying, tapes are classified based on the material used for their construction. 1. **Steel Tapes (Metallic Tapes):** These are the most common type of metallic tapes. They are made of steel or steel alloy and are preferred for their durability and higher accuracy compared to cloth tapes. They are used for general engineering surveys. 2. **Invar Tapes:** While Invar (an alloy of nickel and steel) is also metallic, it is specifically categorized as an 'Invar tape' rather than a general 'metallic tape' because of its extremely low coefficient of thermal expansion. Invar tapes are used for high-precision baseline measurements, not general metallic taping. 3. **Cloth and Wire Tapes:** These are composite tapes. A cloth tape is non-metallic, and a cloth-wire tape is a hybrid. 4. **Nickel:** Pure nickel is not used to manufacture surveying tapes due to cost and physical properties. Therefore, when a question asks generally what 'metallic tapes' are made of in the context of standard surveying equipment, the correct answer is Steel.

In chain surveying, ranging rods are used to mark the positions of stations and to align the chain line between two points. For a ranging rod to be effective, it must be visible from a distance and stable enough to be held vertically. Standard surveying practice specifies that ranging rods are typically made of wood or metal, painted in alternate bands of red and white (or black and white), and have a length ranging from 2 meters to 3 meters. This height ensures that the rod is visible over tall grass or small obstacles while remaining portable and easy to handle for the surveyor. Options a, c, and d are incorrect as they either fall below the minimum visibility threshold or exceed the practical handling limit for standard ranging operations.

The Global Positioning System (GPS), operated by the United States, is designed to provide global coverage. To ensure that at least four satellites are visible from any point on Earth at any time, the system utilizes a constellation of at least 24 satellites. These satellites are distributed evenly across 6 orbital planes (orbits). Each orbital plane is inclined at 55 degrees relative to the Earth's equator, and the planes are spaced 60 degrees apart. This configuration ensures optimal spatial geometry for precise trilateration. Therefore, 24 satellites divided by 6 orbits equals 4 satellites per orbital plane.

Plane Table Surveying is a unique method of surveying where the field observations and the plotting of the map are done simultaneously in the field. Unlike other methods where data is recorded in a field book and plotted later in an office, the plane table allows the surveyor to plot the points and lines directly on the drawing sheet while observing the ground. Why other options are incorrect: - a. Chain Surveying: This is a linear measurement method where data is recorded in a field book and plotted later in the office. - b. Compass Surveying: This involves measuring angles and distances; the data is recorded in a field book and plotted later. - d. Contour Surveying: This is a method used to determine the relief of the ground (elevation) and can be performed using various instruments (like levels or theodolites), but it is not defined as a 'graphical method of simultaneous plotting'.

Step-by-step analysis of the options: 1. **Sextant (Option c):** A sextant is a doubly reflecting instrument used primarily in navigation and surveying to measure the angular distance between two visible objects (e.g., the angle between a celestial body and the horizon). It is specifically designed for the measurement of angles. 2. **Geodimeter (Option a):** This is an electronic distance measurement (EDM) instrument that uses light waves (infrared) to measure the distance between two points. It is used for linear measurement, not angle measurement. 3. **Tellurometer (Option b):** This is an EDM instrument that uses microwave signals to measure long distances. Like the Geodimeter, it is used for distance measurement. 4. **Telescope (Option d):** While a telescope is a critical component of angle-measuring instruments (like the Theodolite or Transit), a telescope by itself is an optical device used for magnification and sighting of distant objects. It does not have the graduated scales required to measure an angle independently. Therefore, the only instrument listed specifically used for the measurement of angles is the Sextant.

In surveying and leveling, the vertical distance of a point above or below a fixed reference surface (called the datum) is defined by two interchangeable terms: 1. **Reduced Level (RL):** This is the technical term used in leveling to denote the vertical distance of a point relative to the datum. If the point is above the datum, the RL is positive; if below, it is negative. 2. **Elevation:** This is a general term used to describe the height of a point above a given reference level (usually Mean Sea Level, which serves as the global datum). Since both 'Reduced Level' and 'Elevation' refer to the same vertical distance from the datum, both options (a) and (b) are correct. Option (c) 'Height of the Instrument' is incorrect because it refers to the vertical distance from the datum to the line of sight (axis) of the leveling instrument, not the distance to the specific point being measured.

In Chain Surveying, the field book is used to record measurements and sketches of the survey area. The standard size of a field book is generally 20 cm x 12 cm. It is opened lengthwise (longitudinally) so that the entries can be made from the bottom of the page upwards, mirroring the direction of the survey progress in the field. This allows the surveyor to easily plot the data later. Option (a) matches the standard technical specification used in surveying textbooks and practice. Options (b), (c), and (d) provide dimensions that do not conform to the standard industry size for a traditional surveying field book.

In Total Station surveying, there are two primary modes of distance measurement: Prism Mode and Non-Prism (Reflectorless) Mode. 1. **Prism Mode**: Uses a retro-reflector (prism) to bounce the signal back to the instrument. Because the prism is highly efficient, the range can be very long (often 3km to 5km). 2. **Non-Prism Mode**: The instrument measures the distance by reflecting the signal off a natural surface (like a wall or rock). Since natural surfaces are poor reflectors compared to prisms, the signal attenuates quickly, significantly limiting the range. While different manufacturers have different specifications, in the context of standard technical examinations for surveyors and common mid-range Total Stations (such as those frequently used in government land revenue departments), the standard rated range for reliable non-prism measurement is typically cited as 200 meters. Beyond this distance, the signal-to-noise ratio becomes too low for accurate measurement unless the target is highly reflective. Therefore, option (a) 200m is the most accurate standard answer for this technical specification.

In leveling, a Bench Mark (BM) is a reference point of known elevation. There are different types of Bench Marks based on their permanence and purpose: 1. **Temporary BM (TBM):** This is a point whose elevation is established for a short period of time. It is typically used at the end of a day's work so that the leveling can be resumed from the same point the next day. It is not intended for long-term use. 2. **Arbitrary BM:** This is a point to which a convenient assumed elevation (e.g., 100.00 m) is assigned. It is used when the absolute elevation (Reduced Level) is not required, only the relative difference between points. 3. **GTS BM (Great Trigonometrical Survey BM):** These are permanent benchmarks established by national agencies (like the Survey of India) with high precision. They serve as the primary reference for all other leveling work in a region. 4. **Present BM:** This is not a standard technical term used in surveying to categorize types of benchmarks. Since the question specifically asks for the benchmark established at the end of a day's work to facilitate the continuation of the survey, the correct term is Temporary BM.

In surveying, the telescope of a leveling instrument contains a cross-hair system (reticle). The primary cross-hairs consist of one vertical hair and one central horizontal hair used for taking precise level readings on a staff. To enable the measurement of distances without a tape (a process called tachymetry or stadia leveling), two additional horizontal hairs are provided—one above and one below the central horizontal hair. These are known as 'Stadia hairs'. The distance between these two stadia hairs is constant (the stadia interval), and by multiplying the difference in readings between the upper and lower stadia hairs by a constant (usually 100), the horizontal distance to the staff can be calculated. Why other options are incorrect: - a. Focusing: This refers to the process or the knob used to make the image of the staff clear, not a physical hair in the reticle. - b. Diaphragm: This is the aperture or the circular opening that limits the light entering the telescope; it is not a hair. - c. Cross hair: While the stadia hairs are part of the cross-hair assembly, 'cross hair' generally refers to the primary central intersection used for leveling, whereas the question specifically asks for the 'two more' horizontal hairs.

An Alidade is a sighting device used in Plane Table Surveying. It consists of a straightedge (ruler) with an attached sighting mechanism (either a plain alidade with vanes or a telescopic alidade) used to draw lines of sight (rays) from the station to the object being plotted. Why other options are incorrect: - a. Tacheometry: Uses a Tacheometer (a transit theodolite equipped with stadia hairs) to measure distances and elevations. - c. Chaining: Uses chains, tapes, and arrows for linear measurements. - d. Compass surveying: Uses a Prismatic or Surveyor's compass to determine the magnetic bearing of lines.

In chain surveying, 'Sag' refers to the phenomenon where a chain or tape hangs in a curve (catenary) between two support points due to its own weight when measured over a long distance or suspended. Because the curved path is longer than the straight-line distance between the two points, the measured length is always greater than the actual horizontal distance. Since this error occurs consistently in the same direction (overestimating the distance) for every length measured, it is classified as a cumulative error. Regarding the other options: - 'Fag', 'Rag', and 'Lag' are not technical terms used to describe sources of measurement error in surveying. They are distractors used in the multiple-choice format.

In surveying, the workflow is broadly divided into two main phases: Field Work and Office Work. 1. Field Work: This involves all activities performed on-site at the location being surveyed. This includes reconnaissance, establishing control points, and the actual measurement of distances, angles, and elevations. 'Setting of instrument' (centering and leveling) is a critical step performed in the field to ensure the instrument is correctly positioned over a station before measurements are taken. 2. Office Work: This involves the processing of the raw data collected during field work. It includes: - Calculation of observed data: Converting raw readings into usable coordinates or distances. - Processing: Organizing the data and applying corrections (e.g., atmospheric or curvature corrections). - Analyzing: Interpreting the results to ensure accuracy and consistency. - Plotting/Drafting: Creating the final map or plan. Since 'Setting of instrument' is a physical activity performed on-site, it is categorized as field work, not office work.

In Plane Table Surveying, there are several methods used to locate points on the map. 1. **Radiation Method**: This is the simplest method where the plane table is set up at a single station. Rays are drawn from this instrument station towards the various points to be located. The distance between the station and the point is then measured and plotted on the map to scale. This matches the description in the question. 2. **Intersection Method**: This method is used to locate points that are inaccessible. It involves observing the point from two different instrument stations; the point is located at the intersection of the two rays drawn from these stations. 3. **Traversing Method**: This is used to establish a framework of stations. It involves moving the plane table from one station to another, drawing a line between them, and repeating the process to create a series of connected lines. 4. **Plane table**: This is the name of the instrument/overall surveying technique, not a specific method of locating a point within that technique.

A deflection angle is the angle by which a survey line deviates from the prolongation of the preceding line. To measure this directly using a theodolite: 1. The instrument is set up at the station where the change in direction occurs. 2. The instrument is first sighted back to the previous station (the preceding line). 3. The horizontal circle (vernier) is then set to 0° (zeroed). 4. The instrument is then rotated to sight the next station (the following line). 5. The reading obtained on the vernier is the direct measurement of the deflection angle. If the instrument were set to 90°, 180°, or 270°, the resulting reading would be an offset value rather than the direct deflection angle. Therefore, setting the instrument to 0° is the standard procedure for direct measurement.

In chain surveying, different types of lines are used for specific purposes: 1. **Check line (or Proof line):** This is a line joined to two points already plotted on the map or measured in the field. Its primary purpose is to verify the accuracy of the fieldwork and the plotting. If the measured length of the check line matches the plotted length, the survey is considered accurate. 2. **Baseline:** This is the longest and most important line in the survey, from which the rest of the network is developed. It is the main reference line. 3. **Survey line:** This is a general term for any line measured in the field (including baselines and tie lines). 4. **Offset:** These are lateral distances measured from the chain line to locate objects or boundaries; they are not used to check the overall accuracy of the field framework. Therefore, the line specifically provided to check accuracy is the check line.