§ 16
Which altitude has point and how much must I raise or lower?
Answer: With the levelling instrument you sight first back at a point with known height (backsight) and then forward at the point you want to know (foresight). Known height plus backsight gives the sight height, i.e. the height of the instrument's line of sight. Sight height minus foresight gives the point's height. The calculator also shows what the staff should show when the point is exactly at the design height, and how many mm you are too high or too low.
Sigtekote = kendt kote + bagsigt
Punktets kote = sigtekote − forsigt
Aflæsning ved projekteret kote = sigtekote − projekteret kote
Afvigelse = (punktets kote − projekteret kote) × 1000 mm. Positiv: punktet ligger for højt og skal sænkes. Negativ: det skal hæves
| Symbol | Meaning | Unit |
|---|---|---|
| fikskote | Known elevation (fixed point or spot height) | m |
| bagsigt | Back sight (reading on the known point) | m |
| forsigt | Foresight (reading at the point) | m |
| projekteret | Design height in the point | m |
| = | Point's height | m |
| = | Sight elevation (instrument height) | m |
| = | Reading when the point is at the projected elevation | m |
| = | Afvigelse fra projekteret kote (+ = for højt) | mm |
Does not apply when
The calculator's own default values inserted. The figures are calculated with exactly the formula the tool uses.
Substituted
Giver
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Med nivelleringsinstrumentet finder du koter og afsætter højder. Beregneren giver punktets kote, sigtekoten og den aflæsning, der giver projekteret kote.
Kotepælen har 12,350. Bagsigt 1,425 og forsigt 1,810. Projekteret kote er 11,950.
It means: Punktet ligger i 11.965 m, sigtekoten er 13.775 m, og afvigelsen er 15 mm, altså for højt. Stadiet skal vise 1.825 m, når punktet er rigtigt.
Fikspunktet har 24,800. Bagsigt 0,982 og forsigt 1,554. Bunden skal ligge i 24,250.
It means: Bunden ligger i 24.228 m, og afvigelsen er -22 mm, altså for lavt. Fyld op og komprimer, til stadiet viser 1.532 m.
Større aflæsning betyder lavere punkt.
Kendt kote plus bagsigt minus forsigt: 12,350 + 1,425 − 1,810 = 11,965.