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1Prepared by: Andre‐Paul C. Ampong
El tElementary SurveyingSu ey g
Horizontal distance measurement
• Methods of distance measurementMethods of distance measurement• Common errors and mistakes in taping
h d f i• Methods of taping• Tape corrections
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Distance by pacingDistance by pacing
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Distance by tapingDistance by taping
• Most common methodMost common method of measuring or laying out horizontal distances
• A form of direct measurement
• Has a relative precision range of 1:1000 to 1:250000
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Distance by tachymetryDistance by tachymetry• Tachymetry is defined as a
d f bprocedure of obtaining horizontal distances and differences in elevation based on the opticalbased on the optical geometry of the instrument employed
• An indirect method• An indirect method• Compared to taping and
differential leveling, the distances and elevationsdistances and elevations obtained by tacheometricmethods are usually of a lower degree of accuracy
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Since ab is equal to a’b’, by similar trianglesq y gf/i = d/s
And d = (f/i)s
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also D = d + (f + c)D = (f/i)s + CD = Ks + C
Distance by graphical and h l h dmathematical methods
• Unknown distances areUnknown distances are geometrically determined through their relationship with known distances
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Distance by mechanical devicesDistance by mechanical devices
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Distance by mechanical devicesDistance by mechanical devices
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Distance by photogrammetryDistance by photogrammetry
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Distance by EDMDistance by EDM
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mindthreshold.wordpress.comSlides may be downloaded from:
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14Prepared by: Andre‐Paul C. Ampong