Site square. All Chapters. The first line of sight is set along the chain line and without disturbing setting right angle line of sight is checked to locate the object. (ii) French Cross-Staff (Fig. Surveying. Cement Testing Lab Equipment. give whole circle bearing (WCB) of a line and quadrantal bearing (QB) of a line respectively. n cross-staff In surveying, an instrument consisting of a staff carrying a brass circle divided into four equal parts or quadrants by two lines intersecting each other at the center. The original Jacobs staff, or cross-staff, was a single pole device credited to Levi ben Gerson (1288-1344), who was one of the leading Jewish mathematicians of the 14th century. : an instrument formerly used at sea for taking the altitude of a celestial body. use in navigation. Therefore, the cross-staff became less popular, and use of this tool eventually diminished. With sighting slits, both are provided as the upper one carries a vernier while the lower part is graduated to degrees and subdivisions. Cross-Staff. The cross-staff consists of a long staff with a perpendicular vane which slides to and fro upon it. D. any angle. ): It consists of an octagonal brass tube with slits on all the eight sides. Up to 90o, 60o, 30o, and 10o, the sides of the cross-staff were usually marked with degree scales, which helps determine your angle. Answer: The French Cross Staff has Eight Faces on it. It has three types: Open cross-staff; French cross-staff; Adjustable cross-staff; The most commonly use out of these is the open cross-staff. To use the cross-staff, start by sliding the cross-piece to about the middle of the yardstick. To mark position of end of the chain or tape on the ground. . All Rights Reserved 2021 Theme: Prefer by. In this survey, the base line runs through the center of the area, so that the offsets are left or right side of base line are fairly equal. The surveyor then reads the angle from the scale on the cross-staff and records the measurement. With open cross-staff (Fig. A staff reading consists of 4 digits. What is cross-staff in surveying? Given two lines of sight, the disc is provided with two saw cuts about 1 cm deep at right angles to each other. The cross-staff was a navigational tool used to measure the angle between the horizon and a celestial body such as the sun or stars. To use the cross-staff, the surveyor positions the instrument in a level position and adjusts the angle of the arms until they intersect with the object to be measured. The modified form of the open cross-staff is the metal arm cross-staff (Fig. The Adjustable. The cross staff is an instrument that is used to measure altitudes and angles consisting of a trigonometrically graduated staff and over it, one or more perpendicular vanes are moving..There are three types of cross staff as given below; Open Cross Staff. Adjustable Cross Staff. Previous Question. . By a circular rack, the upper cylinder can be rotated relative to the lower one, and by screw, the pinion arrangement is actuated. Its 2 types & Advantages, Traversing in surveying | Its 4 Methods & Types. French Cross Staff with Pole Online - It consists of an octagonal brass tube Buy French Cross Staff with Pole Online Price in Delhi, India. a. Open cross staff has two . By 1750, the octant was the preferred tool for measuring altitude. C. adjustable cross-staff. The simplest instrument used for setting right angles is a _____ Metric chains are generally available in _____ It works on the principle of the parallelogram. . The modified form of the open cross-staff is the metal arm cross-staff (Fig. The cross-staff is an instrument that is used to measure altitudes and angles consisting of a trigonometrically graduated staff and over it, one or more perpendicular vanes are moving.Jul 15, 2020. Arrows. They are solid staff, folding staff and telescopic staff. What is cross-staff in civil engineering? It allowed a straightforward measurement of the angular separation of two celestial objects, or the angular diameter of a single object. Dumpy Level: least count 5mm as it is based on staff reading that why least the count is 5mm. Open Cross Staff: It is a simple. Astronomers used the cross-staff for measuring the angle between the directions of two stars. At one end of the primary staff against his cheek, the navigator is placed to observe the sun, Polaris, or another bright star, and the transom is adjusted so that the bottom edge touches the horizon and the top of it aligns with the celestial object. 26 related questions found. The angles can be then measured by holding it so that the ends of the vane are in level with the points that need to be measured. The cross staffs are mounted on a stand. The cross-staff is an instrument used to measure angles and altitudes, consisting of a trigonometrically graduated staff and one or more perpendicular vanes moving over it. 12.14 (b)), an even 45 angle can be set. French Cross Staff. If my lectures are helpful to you please do support and encourage me to do many more civil engineering videos.Hope my classes are helpful for your preparation.\"if not please ignore\"..\" THANK YOU FOR YOUR SUPPORT \"#civilengineering#surveying#chainsurvey#offset#crossstaff#bhoopeshsir#mtcc#civil#opencrossstaff#plusshapecrossstaff#bteup#civilguruji #civilengineerstraininginstitute #practicalsitetrainingcylindrical optical squareoffset instrumentsoffset in surveyingcross staff surveyoptical square surveyingOffsets in chain surveyOffset in chain surveying in HindiDiploma in Civil EngineeringCIVIL ENGINEER SITE TRAININGPolytechnic In civil Engineeringsurveying in civil engineeringsurveyingsurveying in civil engineering 3rd semsurveying in civil engineering 3rd semestersurveying in civil engineering in hindisurveying ssc jesurveying lectureoptical square surveyingoptical square surveying practicaloptical square surveying in hindioptical square workingoptical square used in surveyingoptical square and prism squarecross staffchain surveyChain surveyCross staffFrench cross staffAdjustable cross staffOffset instrumentOpen Cross Staff In Surveyinghttps://youtu.be/ws2r8R8OfWUFrench Cross Staff In Surveyinghttps://youtu.be/Vocqjdna2CM Optical square - an improved version of the . To measure altitude or the distance of an object above sea level or the horizon the cross-staff is used and it is an early navigational tool. These open frame tripods are comes with lemon yellow powder coated and silver anodized. The least count of a leveling staff is 5 mm. What is Open Cross staff and French Cross staff? The modified form of the open cross-staff is the metal arm cross-staff (Fig. All Categories . The first digit represents the whole number of . Home | About | Contact | Copyright | Privacy | Cookie Policy | Terms & Conditions | Sitemap. 12.14 (a)) it is possible to set perpendicular only, while with french cross-staff (Fig. . French cross staff ! Ships officers used it to measure the elevation angle of the noontime Sun above the horizon, which allowed them to estimate their latitude (see section on navigation). The Adjustable cross-staff. Hamad Surveying 05/10/2021. The two types of offsets are, (i). Open cross staff . What is the least count of Levelling staff? Features: Used to measure the altitude of the sun. The pole was marked in degrees, and the altitude of the stars could be determined by using a sliding wooden panel on the rod. D. higher level to lower level. In many cases, John Daviss invention ended up replacing not only the cross staff, but also the mariners astrolabe and quadrant. 3.9. declination. What is driven or filled in the soft ground during the marking of survey stations? Used as a navigation instrument. The reading which can be read directly by the instrument man through the telescope is called self-reading staff. What is the difference between JFS and JFS2 in AIX? Line ranger is an optical instrument used for locating a point on a line and hence useful for ranging. The cross-staff Each Face is connected to the other with a 45 Degree Angle. The staff reading is the reading on the staff at which the horizontal hair appears to cut the staff. Classify them. For setting out right angles, these are used and sights are about 8 cm. It is so clearity of information, Share this information with Your Friends & Spread the love, Disadvantages of glass fiber reinforced Gypsum, What is Grouting ? If my lectures are helpful to you please do support and encourage me to do many more civil engineering videos.Hope my classes are helpful for your preparatio. In the 16th century, it became a mariners navigational instrument. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); 2022 FAQS Clear - All Rights Reserved An optical square is used for the same purpose as the cross-staff, but it is more accurate. surveying Objective type Questions and Answers. 90 only. Cross-staff. By the Jewish philosopher and scientist Levi Ben Gerson, cross-staff was described in about 1342 and for astronomical and surveying purposes it is originally used. Explanation: Pantagraph: Pantagraph is an instrument used for reproducing the map (whether to enlarge or to reduce). This measurement is known as your backsight. By knowing this angle, a navigator could then determine his latitude and direction. Open cross staff. ADJUSTABLE CROSS STAFF: It consists of two cylinders of equal diameter placed one over each another and is used to set of any angle. The cross-staff is a simple instrument that is widely used in surveying operations. 15 . This playlist especially has made for Engineering students'.The topic Chain Surveying is a part of Surveying which is studied vastly in Civil Engineering. There are three types of cross-staff as given below; The open wooden cross-staff is the simplest form of cross-staff and it consists of about 4cm thick round or square piece of wood and in diameter varying from 15cm to 30cm. What are offsets? Chains - In chain surveying chains are the most important equipment for the procedure of survey. 3.8) in which the wooden head is replaced by four metal arms with vertical slits for sighting through at right angles to each other. It was in the late 1700s when the octant and sextant became the new preferred tools over the back staff. An offset is the lateral distance of an object or ground feature measured from a survey line. Type of cross-staff which is also used to set out 900.There are three types of cross-staff: The cross-staff consists of a long staff with a perpendicular vane which slides to and fro upon it. Which of the following angles can be set out with the help of French cross staff? View all Chapter and number of question available From each chapter from Surveying . While the astronomical cross-staff was used in surveying for measuring angles, two other devices referred to as a cross-staff were also employed. When You Breathe In Your Diaphragm Does What. What is the healthiest blood type to have. If my lectures are helpful to you please do support and encourage me to do many more civil engineering videos.Hope my classes are helpful for your preparatio. Civil Engineering Mcqs. An optical square is used for the same purpose as the cross-staff, but it is more accurate. The cross-staff is also referred to as the fore-staff and the Jacob's staff. There are three types of cross-staff: Open cross-staff; . (ii) French Cross-Staff (Fig. The cross-staff is also referred to as the fore-staff and the Jacob's staff. Open cross staff French cross staff Adjustable cross staff Optical square. What is a cross-staff in surveying? To measure the slope of ground. Products search. What is Open Cross staff and French Cross staff? 1)Open cross-staff The cross-staff is an instrument used to measure angles and altitudes, consisting of a trigonometrically graduated staff and one or more perpendicular vanes moving over it. The French versions were frequently eight-sided rather than round. What is the least count of reading for self reading staff? The cross staff is an instrument that is used to measure altitudes and angles consisting of a trigonometrically graduated staff and over it, one or more perpendicular vanes are moving.There are three types of cross staff as given below; The cross-staff was used into the 17th and 18th centuries. While the length of the whole chain is measured from . A. open cross-staff. It may be mounted on the pointed staff when in use because it carries a socket at the base and it is not as accurate as the open cross-staff due to the sights being too close. Cross-staff is used for setting out right angles and French cross-staff is an advanced version of cross-staff and can set out 45-degree angles also. The diagonals of the prisms are silvered so as to reflect the rays. Required fields are marked *. The open cross-staff consists of four metal arms with vertical slits. Prism square (iv). Type of cross-staff which is also used to set out 900.There are three types of cross-staff: Open cross-staff. ): It consists of an octagonal brass tube with slits on all the eight sides. Hint Answer. Save my name, email, and website in this browser for the next time I comment. a) Finding out foot of the perpendicular from a given point to a line b) Setting right angle at a given point on a line There are three forms of cross staff. 45 only. H. The French cross-staff and. It had two sets . Explanation: The three types are open cross staff, French cross staff and adjustable cross staff. So helpful for diploma students Adjustable cross staff ! A staff reading consists of 4 digits. While the astronomical cross-staff was used in surveying for measuring angles, two other devices referred to as a cross-staff were also employed. For setting out angles of any magnitude it may be used and it may serve to take the bearing of the line because it has a magnetic compass at the top. Cement Sampler; Blain Air Permeability; 13.The horizontal angle between the true meridian and magnetic meridian at a place is called. The cross staff is used to set out the perpendicular directions for offsets. The instrument was mainly used for finding the latitude by measuring the altitude of the polar star and for measuring the altitude of the sun. Who Can Benefit From Diaphragmatic Breathing? The French and. It is suitable for setting out right angles on a required survey line. 256. A. . To mark survey stations and endpoints of survey lines on the ground. You are Viewing the Premium Content of Introduction-to-Surveying Under Free Trial Section. The metal arm cross-staff is the modified form of the open cross-staff in which sighting through at right angles to each other wooden head is replaced by four metal arms with vertical slits. The cross-staff is an instrument that is used to measure altitudes and angles consisting of a trigonometrically graduated staff and over it, one or more perpendicular vanes are moving. It consists of an octagonal brass tube with slits on all the eight sides. For measuring the altitude of the sun and for finding the latitude by measuring the altitude of the polar star, the instrument was mainly used. Cross staff. By the point where the main staff between the transom matches the degree scale, the altitude is determined and the navigator will use charts and maps to determine his latitude from here. 2 Answers. 3.8) in which the wooden head is replaced by four metal arms with vertical slits for sighting through at right angles to each other. The first digit represents the whole number of meters, the second digit represents decimeters, and the third, and fourth digits represent millimeters. 3.9. The cross-staff was an observing tool developed by Levi ben Gerson (1288-1344). Your email address will not be published. Used to set out either 45 or 90. Cross Staff. Beside above, what is Open Cross staff . French cross-staff consists of an octagonal brass tube with slits on all the eight sides . The length of the links is the distance between the centre of two consecutive middle rings. Cross-head, cross-sight, surveyor's cross or cross - a drum or box shaped device mounted on a pole. C. lower level to higher level. The term cross-staff may also have a different meaning in the history of surveying. (ii) French Cross-Staff (Fig. 3.8) in which the wooden head is replaced by four metal arms with vertical slits for sighting through at right angles to each other. Sight the yardstick along the line halfway between the stars whose separation you want to measure, then place the two sliders on the cross-piece so that the slits are approximately where the stars are located. 3.9. Optional Square. magnetic bearing. Explanation: The three types are open cross staff, French cross staff and adjustable cross staff. Is the cross-staff still used? From its look and shape the cross-staff gets its name and it was with four different sized movable crosspieces and about 3 feet long. Lacquered brass surveyor's octagonal cross-staff head surmounted by a compass with 2" black dial and silvered scale, displaying French cardinals "N, E, S" and "O." Fine needle seated on a jewelled bearing, blued to indicate north, sliding transit lock to exterior. cross staff. If my lectures are helpful to you please do support and encourage me to do many more civil engineering videos.Hope my classes are helpful for your preparation.\"if not please ignore\"..\" THANK YOU FOR YOUR SUPPORT \"#lineranging#chainsurvey#civilengineering#__ metric jarib1 jarib me kitne fit hota haiguniya nikalne ka formulaobstacle in chaining surveyobstacle in chaining at siteindirect ranging in surveyingobstacle in chainingobstacle in chaining in hindiJarib#surveying#frenchcrossstaff#offset#crossstaff#bhoopeshsir#mtcc#civil#opencrossstaff#plusshapecrossstaff#bteup#civilguruji #civilengineerstraininginstitute #practicalsitetrainingcylindrical optical squareoffset instrumentsoffset in surveyingcross staff surveyoptical square surveyingOffsets in chain surveyOffset in chain surveying in HindiDiploma in Civil EngineeringCIVIL ENGINEER SITE TRAININGPolytechnic In civil Engineeringsurveying in civil engineeringsurveyingsurveying in civil engineering 3rd semsurveying in civil engineering 3rd semestersurveying in civil engineering in hindisurveying ssc jesurveying lectureoptical square surveyingoptical square surveying practicaloptical square surveying in hindioptical square workingoptical square used in surveyingoptical square and prism squarecross staffchain surveyChain surveyCross staffFrench cross staffAdjustable cross staffOffset instrumentLine rangingdirect line rangingindirect line ranging B. french cross-staff. To measure altitude or the distance of an object above sea level or the horizon the cross-staff is used and it is an early navigational tool. Then, record the measurement indicated by your devices center, horizontal crosshair. open Cross staff ! If my lectures are helpful to you please do support and encourage me to do many more civil engineering videos.Hope my classes are helpful for your preparatio. The user would also have four crosspieces of varying lengths and based on the height of the angle being measured, navigators would typically use only one at a time it also measures angles up to 90o, 60o, 30o, and 10o and also known as transoms. The Open cross-staff consists of a long staff with a perpendicular vane which slides to and fro upon it. How many types of cross staff are available? The cross-staff was a navigational tool used to measure the angle between the horizon and a celestial body such as the sun or stars. The fundamental principle of surveying is to work from the A. whole to the part. Answer: A. open cross-staff 255. The octagonal body with pierced slots holding cord reticles . B. part to the whole. Open cross staff has two vertical, opposite slits. azimuth. 14.The prismatic compass and surveyor's compass. From Wikipedia, the free encyclopedia. The two pairs of arms (AB and BC) are at right angles to each other. French cross-staff consists of an octagonal brass tube with slits on all eight sides and on each of four sides, it has an alternate vertical sighting slit and an opposite vertical window with a vertical fine wire. Find the height difference between your level and the benchmark spot. We mark the staffs with graduated measurements which are precise. A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points or heights of points above a vertical datum. Adjustable cross-staff consists of a brass cylindrical tube about 8 cm in diameter and 1 cm deep. By knowing this angle, a navigator could then determine his latitude and direction. To determine altitude a navigator would hold it near his eye and take measurements. Next Question. Cross staff: The cross staff is used for. local attraction. 1. It cannot be used without a leveling instrument. Skip to the content +91-8448366515. optical square. Look through your dumpy levels telescope and locate the E staff. ): It consists of an octagonal brass tube with slits on all the eight sides. than its 16th-century successor, the cross-staff, a simple device consisting of a staff about 3 feet (1 metre) long fitted with a sliding crosspiece (see photograph). A cross-staff is a surveying tool used to measure angles and elevations. B. Prism square, the first one is commonly use. How do you read a cross-staff? 10. There are usually three forms of self-reading staff. Open cross staff b.French cross staff c.Adjustable cross staff (ii). The chains are the straight links of galvanised mild steel wire bent into rings at the ends and joined each other by three small circular or oval rings. The term cross-staff may also have a different meaning in the history of surveying. The staff reading is the reading on the staff at which the horizontal hair appears to cut the staff. To indicate whether the line is vertical or not. The vertical slits are meant for sighting the object and the ranging rods. The pole is fitted with an iron shoe. The cross-staff is mounted on a wooden pole of length 1.5m and diameter 2.5 cm. what is Cross staff. We mark the staffs with graduated . D. optical square. (i). Your email address will not be published. It consists of two isosceles prisms placed one over the other and fixed in an instrument with handle. A target staff is the one in which the reading is taken by a person holding the staff. Chain survey ! The cross-staff is an instrument that is used to measure altitudes and angles consisting of a trigonometrically graduated staff and over it, one or more perpendicular vanes are moving. Open cross staff French cross staff Adjustable cross staff German cross staff. Answer: A. whole to the part. Optical square (iii). How many types of leveling staff are there? 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