Misclosure - Notes PDF

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Lecture Notes...

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Misclosure: E = Allowable misclosure N = Number of instrument setups/length of circuit (in km) M = Weather/Setting value M = 5mm if Flat Ground, Good Weather M = 12mm if Hilly Ground, Windy Bad Weather

Theodolites measure directions Angles – Minutes – Seconds (⁰)

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e.g 20-32-14 is 20⁰ - 32 minutes – 14 seconds Used when measuring the direction of Point, A to Point B when it is not a straight direction measurement (at an angle) The minutes and seconds are maximised at 60 just like a normal minute and second 60 seconds in a minute 60 minutes in an angle 1⁰ = 60’ = 3600” 1’ = 60”

Basic Features: Trivet – Base Plate and clamping screw Tribrach – Circular bubble, plate bubble, 3-foot screws and optical/laser plummet Horizontal – Upper plate reference mark (which rotates) and Lower plate 360⁰ glass circle (fixed) Eye scope – Lens Telescope – Object Lens and Focusing Lens (The two lens systems with crosshairs)

Abstract angle = Each Mean angle – First Mean angle Measuring Horizontal Angles

Mean = [ FL + (FR-180) ] ÷ 2 Measuring Vertical Angles

Abstract = Mean – First Mean angle...