Surveying Traverse Practical Report

Errors

Horizontal Angle ReadingsThe reading of the horizontal angles was incorrect because of the way we measured them. We recorded the horizontal and vertical angles at the same point, parallel to the ground (i.e. to a point on the person standing over the mark). We only realised this in hindsight after discovering our large angular misclose. What we should have done was measure the horizontal angle directly to the mark on the ground. Over a number of readings, this error is what contributed to our large misclose of -5°21’30”. To work this out we used the formula (2n-4) x 90° = 180° to find the internal angle sum of the traverse points. Our angle sum using the values calculated on the theodolite equated to 174°38’30” therefore less than the allowable angle sum.

Vertical Angle ReadingThe vertical angle reading was slightly skewed due to the positioning of the person over the point on the ground that we were measuring to. To obtain a vertical angle reading parallel to the surface of the ground, the theodolite was aimed at a point on the person at the same height as the height of the instrument. This in itself is a fairly accurate measurement but with no clear way of telling if the person is directly over the mark or if their body is vertical, its hard to obtain an exact measurement.

Distance ReadingsWhen measuring the surface distance with the measuring tape, the reading will not perfect because of the inconsistencies of the surface of the ground. The error in our measurement was on minimal due to the relatively flat surface of the ground, however there is still an error.