Locating a new point by intersection from two traverse stations
A point on the far side of a river is fixed by directions observed from two established traverse stations, then verified independently by the sine rule and by a third-angle check.
Apply· about 24 minutes by hand· 5 steps
Given
Two established traverse stations: STA 12 at N 8240.65, E 6115.30 and STA 13 at N 8905.44, E 6742.88, US survey feet.
A new point P, a rock outcrop across a river, cannot be occupied or taped. It is visible from both stations.
At STA 12, with a backsight on STA 13, the angle turned clockwise to P is 31°54′20″.
At STA 13, with a backsight on STA 12, the angle turned counter-clockwise to P is 84°45′10″.
Both angles were turned in two sets with a 5 second instrument.
Coordinates to 0.01 ft, angles to 1 second.
Required
The azimuth and length of the base line STA 12 to STA 13.
Azimuths from each station to P.
The coordinates of P.
The distances from each station to P.
Work it through yourself before reading on - the solution below shows every step, so there is no way to skim it without giving the answer away.
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