The errors which are accumulate at the end of the survey are known as Cumulative errors. These type of errors occur when we contradict the main principle of Survey which is
To work from whole to part.
When we work from part to whole* than errors are magnified in the end and the process becomes
uncontrollable at the end.
Part to whole means that first we surveyed small triangles and then expand these small triangles
into large triangles covering the area.
The error in survey in the small triangles will be magnified when we expand it to large