The starting point must be fixed so it can be reproduced. Its distance from the corner of the building is indicated in the drawing. The simplest form of rectangular coordinate system. Using a straight line between two known points, items are measured along the line and perpendicular from the line. Inside or outside of a house, this line can be a straight wall.
Outdoor scenes can use a string or long measuring tape as the reference or base line.
This technique is particularly appropriate in a room with perpendicular walls or outdoors with perpendicular streets. Beginning from a known point and known direction, a distance and azimuth are measured to an intermediate point. From that point a distance and azimuth are measured to a second intermediate point, etc. Continuing to measure to intermediate points until one arrives back at the origin is called closing the survey. By closing the survey one can calculate the error included.