Drawing error ellipses on a digital flatbed plotter
Brenton J. Burford · Australian Surveyor · 1975
The advent of electronic computers has made the acquisition of the variance-covariance matrix from a co-ordinate adjustment a relatively simple procedure. A subsequent extension of this is the construction of the standard and relative error ellipses which have two major but distinct applications viz: (i) they are useful in determining any apparent weaknesses in observed networks or traverses; (ii) they are ideal for the examination of simulated networks or traverses. In the past the plotting of these ellipses has been a cumbersome task when undertaken by hand using a geometrical approach. A digital flatbed plotter can neatly and quickly construct the standard and relative ellipses with their pedal curves. This paper does not introduce new theory but utilises existing theory for a practical application.