LSQ is an application for carrying out Least Squares
reduction of Survey data within a Cartesian grid system.
This can either be a simple orthogonal system (with
allowance for Earth curvature), or a grid based on
Transverse Mercator projections: currently, LSQ supports
the British National Grid and Universal Transverse Mercator
(UTM) projections. There is also a facility to set a Scale
Factor for the simple grid, which means that LSQ can also
be used for all except very large surveys in any other
conformal projection system.

The input data can be read in from a file or typed
directly into the program, and consists of:

1. The projection system or Scale factor to be used;

2. The exact co-ordinates of relevant known stations, and
the approximate co-ordinates of the unknown ones;

3. The observations taken from each station. These can
include horizontal angles and distances, vertical angles,
true bearings, or horizontal and slope distances to other
specified stations. Levelling and Differential GPS data is
input as positional differences in grid co-ordinates.

The output of the application includes the estimated
positions of the unknown points, plus an indication of how
much each observation had to be 'adjusted' to reach these
results. If there is a gross error in the observation data,
then some of the adjustments will be larger than might be
expected: LSQ allows the user to selectively reject
observations, as a means of finding the one which is
causing the problem.

The final results also show the 'error ellipse' for each
unknown point, giving the volume (or area for 2-D work) of
one standard deviation, based on the apparent spread of
errors from the observations.

Winzip is required to download this program

No support on the downloading of this program will be
provided

Click on the link below, and choose 'Save it to disk' or
'Save' when the pop-up window appears. Navigate to the
desktop in the 'Save in' window, and click 'Save' to start
the download



When the download is complete, double-click on 'LSQ
Package.zip', which will now be on your desktop. Use the
'Extract' command to extract all the files in the archive
onto your desktop. You will be prompted for a password,
which is the first word on page 79 of Plane and Geodetic
Surveying.

A folder, also called 'LSQ Package', will be created on
your desktop. Inside this folder, you will find a file
called 'Readme.txt'. Double-click on this to find further
instructions for installing LSQ. Once LSQ is installed, the
two 'LSQ Package' items can be deleted from your desktop,
or moved elsewhere for storage.

If you have any problems using LSQ, please contact Aylmer
Johnson at alj3@cam.ac.uk. The software contains a manual.