Question

es a . the data for a 4 set-up differential leveling loop, that besins and ends on Bm A (308.23), is provided in the table below, All the data is in units of fect. a.) Prepare the level notes 6.) Prepare a pase check and adjust the misclosure 1 c.) if order of the in survey do the results loop distance 1200 ft. at what 7 quality. I mostly interested in part c. -S(FS) Point AS (BS) BMA 10.53 2,96 TPI 18:57 TP2 a.o) / 4.66 11.69 TPB 1.5) 10.35 BMA

Answer 1

Formula used :

HI= Elevation +BS

Elevation= HI(prev. row) - FS

station	BS	HI	FS	ELEVATION
BM A	10.53	308.23+10.53 =318.76		308.23
TP 1	8.57	315.8+8.57=324.37	2.96	318.76-2.96=315.8
TP 2	9.01	319.71+9.01=328.72	4.66	324.37-4.66=319.71
TP 3	1.51	317.03+1.51=318.54	11.69	328.72-11.69=317.03
BM A			10.35	318.54-10.35=308.19 (ACTUTAL=308.23)

CHECK

$\small \sum$ BS =29.62  $\small \sum$ FS =29.66 $\small \sum$ BS-$\small \sum$ FS = 29.62-29.66 = -0.04

LAST ELEVATION- FIRST ELEVATION = 308.19-308.23= -0.04

AS $\small \sum$ BS-$\small \sum$ FS =LAST ELEVATION- FIRST ELEVATION =-0.04

HENCE TABLE PREPARED  IS OK.

MISCLOSURE = 648.47-648.51 = -0.04

order of levelling

length of circuit = 1200/5280 =0.22727 mile

error = 0.04 ft

for first order levelling permissible error = ft. =0.008 ft

0.01770.22727

for second order levelling permissible error = =0.0167 ft

0.03570.22727

for third order levelling permissible error =ft=0.0238 ft

0.0570.22727

AS error is more than permissible error in all orders, the order is higher than three orders (fourth order of levelling)