How to draw up your Site Survey and Analysis Plan.

Welcome back!

How did you get on with that jigsaw? Or did you take one look at it and panic like I did? Either way, I hope you had a good weekend.

Today, we're going to look at all of the measured and non-measured information that you've got from your garden, and we're going to draw it up in to our Survey and Site analysis Plan. Finally!

Don't panic! It's not that bad! Just a little time consuming, depending on how good you are a technical drawing.

The first thing you need to do is to decide what size scale you need to use. As mentioned before this will be based largely on how large your garden is. If your garden is huge - you lucky things- then you will probably have to use a scale of 1:200, but this is best avoided as you will not be able to add much detail and will be quite hard to draw.

For those of us with normal sized gardens, and those that are the size of a postage stamp, I'd recommend using a scale of 1:100 or 1:50. Whichever scale you chose though, you will need to measure the longest widths and lengths onto your paper to make sure that they fit. Not only do your longest measurements need to fit, but you will need to have ample room around your drawing to be able to make comments. If you try to crowd it into small gaps it will look muddled and confusing, and you probably won't have a clue what you were talking about when you come to use your plan. You will also need to decide the best angle for your piece of paper - horizontal (landscape) or vertical (portrait) - to allow for your drawing. It is usually best to try placing your building at the bottom of the page and working up from that.

Remember to mark on your plan what scale you are using and which way north faces.

For this to work you will need:

Tracing paper
Masking Tape
Smooth 'underlay' paper
Scale ruler
Retractable pencil (0.5mm lead)
T-Square
Adjustable set square
Beam Compass
Drawing Board (optional)

Using the masking tape, secure your underlay paper to the table top or the drawing board. You could use graph paper for this which will give you some sense of scale but it is worth remembering that very few, if any, of your measurements will exactly fit this. Next secure your chosen size of tracing paper over the underlay paper making sure that you can see the lines of the graph paper through it. You must ensure that any vertical or horizontal lines that or are draw on the plan are true and square. Otherwise you will end up with many errors and the plan will be inaccurate and meaningless.

The first line to draw will be your baseline of the house. Draw it in exactly the same direction that you took the original measurement. Next you will need to plot your boundary corners and draw in the lines to your boundary.

To plot your corners, refer to your triangulation notes. Use your scale rule to adjust your beam compass to correspond with your first measurement from, the fixed point at the house to the boundary corner. Now place the 'spiked' end of the beam compass at the location of the fixed point of the house on the drawing, and, using your best guesstimate, hold the pencil end of the compass in the area you believe the boundary corner to be. Then, when you're fairly happy with the position, scribe an arc in that area. Repeat this process with your second triangulation measurement (probably from the other fixed point on your baseline). Where the two arcs meet - that is the actual position of your boundary corner.

Easy, huh?

Continue this process for each point that you have triangulated in the survey. Once you have your boundary plotted, you can then continue to fill in the rest of the drawing. Plot everything that you measured on-site and write information around the edges to complete the analysis. (See Diagram Below)
For features that you measured using the 'offset' method, you will need to plot them onto your drawing in exactly the same method - plot the baseline you used and measure from each point along it, just as you did in the garden.


If measurements are not adding up now that you are putting them onto paper, you probably made an error in the recording stage and will need to re-measure. Don't beat yourself up over it. Simply pop back out to the garden and re-measure - problem solved!

Take as much care with drawing as you did with the measuring. Your plan needs to be as accurate as humanly possible.

And that's all there is to it! It's fairly simple - it's just really time consuming!

Taking a separate piece of paper, you will need to draw up elevation drawings to accompany your Site Survey Plan. Work through your measurements in the same order that you took them, starting from the baseline. Add written information to relate to features along the house front (or whatever the subject of the elevation is) onto your new elevation plan. I'll go into elevation drawings at a later date so don't worry if you can't get the hang of it yet.

The important thing at the end of this stage is that you know exactly what exists in your garden and have an accurate drawing, or drawings, recording that information.

If you're satisfied that you have done all of that -Well Done!. You are now on your way to becoming a garden designer!

The next thing we'll look at, is trying to decide what you might like in your newly-designed garden.

Knowing how to make your Measurements

Right! Back for the next step already?

We are, you'll be pleased to hear, onto the last stages of recording measurements on-site. Now that you've calculated all of the baseline details you're ready to measure the rest of the garden-hooray! First things first, you'll need to measure the boundaries. At this point it's worth pointing out that your garden, in most cases, will not be square (or rectangular). Even if you have an amazing eye for details and would swear to a court of law that yours is square (or rectangular), it's worthwhile checking these things properly, all the same. Most gardens are an irregular shape - which is really annoying at times! - and it is necessary to get these measurements absolutely correct. Am I repeating myself here? Sorry, but it really is important to measure your garden accurately.

There are a few techniques used in carrying out a site survey. Let's look at two of them in detail.

Triangulation

This technique helps to establish correct angles and is excellent for measuring boundaries. Also, if you have a random tree (or other feature) on-site that you cannot measure from the baseline, then triangulation would work well for this too.

In order to use triangulation, you will need two fixed points that feature on the baseline. In other words, you need to refer to two known measurements from your baseline. It is usually the two corners of the house, but it could be any measurements you want to use. It will be easier to do if they are some distance apart though, as they'll be less cluttered on your rough survey plan. In case I've confused you, your rough survey plan is the bit of reasonable sized paper on your clipboard that you've sketched your baseline measurements on. Once you've established your two fixed points, simply take your second 30- metre tape and measure from each fixed point to the item that needs measuring. In the first instance this will be the top boundary corner of the garden. When you put these two measurements together they will form a triangle and establish the exact position of the boundary corner (or whatever item it is that you're measuring at the time).

Recording this on your rough survey plan, you will find it less confusing at a later date to ensure that you label each fixed point (see diagram below).

In the diagram, you can see that 'point A' and 'point B' are on the baseline and the item being measured, in this case, the boundary corner, is 'point G'. Note the triangle that is created from the two measurements.

Always make sure that the two measurements are taken to the item in the exact same place. If you were to measure a tree, for example, and with one reading you went one side of the trunk, but with the next reading you went to the other side of the trunk, it could be very inaccurate - depending on how old the tree is! You would need to measure in the centre of the trunk, or, do two different triangulation measurements of the tree and later measure its circumference.

If an item that you need to measure is too far away from your baseline's fixed points, then you will need to establish new fixed points closer to the item. This is okay to do so long as you ensure the accuracy of these new fixed points. You can have as many fixed points on-site as you require. Try to keep it as simple as possible though otherwise you'll end up in a right pickle when you come to draw it up later.

Once you have established the boundary corners you can continue to measure the lengths of the boundaries and record the results onto your rough site survey. When you come to create your design, you will need to know who owns each boundary. If you decide to do something spectacular with it and your neighbour owns it, you may end up in all sorts of trouble. Don't forget to write down any information about the boundary itself in your little note pad. Include features such as, what material the boundary is made of, it's height and what condition it's in. If you're looking at a fence, then you'll need to measure each panel and so forth. You will benefit from knowing as much as possible about your garden. Get intimate with it!

You can measure all of the features along your boundary by repeating the same process that you used for the baseline. There may be other features along the boundary that you will also need to record. Flowerbeds, plants, pond or structures may all be present. If you are measuring flowerbeds, you will need to record the position of plants in the bed. This may make your rough site survey too crowded and you may find it easier to complete a seperate sketch for each flowerbed. To measure the plants you will need to start from your boundary and run your measure to the centre of the plants. This is actually an offset measurement, which we'll look at in a moment. For large, spreading plants you will need to record the spread too. It would be helpful if you were able to identify the plants that you're measuring. Don't worry, we'll look at that plant identification later too.

For all internal features on-site you will need to decide whether the triangulation method is the best to use, or whether you would get a better result using the offset technique. Both methods are fine and you will probably have to use both during the survey. So long as, whichever technique you are using, the measurements come from a fixed point.

Offset measurements

These are excellent for determining an irregular shape such as lawn edges, flowerbeds and ponds. You will need to introduce a new baseline that is in a more convenient position. Wherever your new baseline is, be it along a fence or down the middle of the garden, make sure you plot that baseline in relation with other fixed points. Using your steel retractable measuring tape, take measurements from your new baseline at right angles to the feature to be measured. Use aset square if necessary, to ensure excat 90* angles. Take measurements at regular intervals along the feature (see diagram below), allowing closer intervals for more curvier subjects. If you find your baseline is greater than, say, 3 metres from the feature you are trying to measure, it would be advisable to move your baseline closer to avoid inaccuracy.

Try to be as methodical as you can when you measure your garden. When you worked on your original baseline, I encouraged you to measure any features that were close by. If you are certain that you have all measurements required in the area of the first baseline, you can move it and use the tape for new baselines around the garden. Unless you want to use this process as a fitness workout and want to run about all over the place, then you'll find it easier, and faster, to measure an area of your garden just once.

Make sure that you record every feature, whether you plan on getting rid of it or not. If you have a summerhouse, that you intend on getting rid of, but later change your mind, you will already have its dimensions and position to hand. Remember to measure heights and thicknesses of retaining walls. With greenhouses and other buildings don't just measure to the apex of the roof but also to the lowest part of the roof. Remember to observe the way the doors open, their width, any other interesting details that you may find helpful later on. You will need to measure any steps in the garden, including the risers ands depth of each step. Any features, such as lighting or handrails will need to be recorded.

Are you exhausted yet? Don't worry you're nearly finished with this stage, then you can move onto more exciting parts of garden design.

If you have got steps in your garden, then that indicates that you must have a change in levels - don't lie to me now, I'll know! Guess what? You'll need to measure the level changes too. I'll go into that next time. Right now though, I'd say you deserve a nice cup of tea/coffee/other after all that hard work!