Simple Garden Surveying - part one

Professional landscapers use a variety of techniques and equipment to create accurate surveys to enable them to plan new garden layouts. Since the advent of lasers it has become inexpensive and easy to utilise this simple tool.

But there is an even simpler solution you can use and I have illustrated in the above MS paint doc.

All surveys have to have a datum - the datum is the mark that all measurements are taken from and charted above or below this mark to enable you to plot it on a side elevation or plan.

When this information is used properly it is possible to work out permutations for steps, level areas or accurate slopes.

Start by putting a single wooden peg in the ground close to a known and existing height. This could be the bottom of a door for example - you know need to project that height measurement to a permanent marker such as a peg in the ground which will become the reference of all the dimensions you are going to take.

Using a straight edge and spirit level put a clear mark on the peg in a coloured pencil or permanent spray. Try to use this colour only once so that you will always be aware it is your starting height.

This will be the start and theoretically you can number it however you want but we will call it zero '0'. Now put a second peg in the ground, and using a spirit level, level it with your datum peg, in the direction aiming towards the furthest point within line of sight.

It is important that the two pegs are accurately levelled because it has a bearing on all further measurements.

With the help of an assistant line this up on a long wooden square pole at the end of the garden and then, either using a string line or line of sight, project a line through the top of the two level pegs to the long pole you have at the end of the garden - make a mark with a pencil on the fence when the three points coincide.

This line of sight can then be used to measure down to ground level. You will then have a relationship to the height of your datum peg and the height you are measuring.

By measuring at 1 metre intervals from the datum in a straight line down to soil level a profile will be formed and can be transferred to paper for plotting on a plan.

If you are working alone then using a fine nylon brick layers line, pulled out the full length of the garden and using it to make your measurements will work the same. The line needs to be very tight to be accurate.

Simple Garden Surveying - Part Two