Difference between Prismatic compass and Surveyor’s compass

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Difference between Prismatic compass and Surveyor’s compass in simple language. Many questions were asked from these differences in Competitive exams like needle size in both the compasses, graduations in both compasses etc. First of all, keep both the compasses in front of you then one by one start matching these differences or just conduct an experiment for a small irregular plot by using these compass and you could also learn WCB system and RB system. So give your best trial.
S.No Prismatic compass Surveyor’s compass
1. Magnetic needle is of broad size. Magnetic needle is of edge type.
2. Graduations (divisions) are in W.C.B system. Graduations are in R.B system.
3. Graduated ring has attachment with needle. Graduated ring has attachment with box.
4. Divisions(readings) are noted down with the help of prism as graduations are inverted. Divisions are noted down directly from top of glass.
5. Reading and sighting can be done at the same time from same position. Reading and sighting can be done separately from different position.
6. For holding, support(i.e. Tripod) are not compulsory. For holding, supports are compulsory.
 7.  Prism at viewing end.  No prism at viewing end, hence there is only a slit.

Contour line:

Contour line is the line which joins the points of same elevation(i.e having same height). Before making contour maps(i.e. plan representing contour lines) we have to know some important properties of Contour lines:-

    • Contour lines (made up of points) have same elevation.
    • Contour lines never cross(intersect) each other because individual lines have its own elevation.
    • Spacing in between contour lines represent quality(i.e. uniform of non-uniform) of ground.
    • Contours may be irregular(i.e.up and down) or plane(straight).
    • Closed contour lines of higher elevation represent summit and closed contour lines of lower elevation represent nadir(depression).

A traverse may be open or closed connected by series of straight lines whose lengths and directions are known to us is called as a traverse. Traverse means to pass through. In traversing the survey line is fixed by taking the angular measurements and distance, by suitable instruments.

Types of traverse:

        • Open traverse :- A traverse in which we does not return to starting point or another point.
        • Closed traverse :- A traverse in which we return to starting point or another point whose location is known to us.

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Arbaj Demrot is the founder of VideRime Online Learning, a leading engineering website. He did his BE Civil and M.Tech Structure from RGPV University, Bhopal and has been working as an Assistant Professor in a reputed college.

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