The drawing of detailed and comprehensive plans and sections is a fundamental part of the recording of archaeological excavations. In the past excavations only recorded archaeological features which were considered to be important at the time of the excavation, such as major walls or graves and ditches. However it has become apparent that the establishment of the stratigraphic sequence and the interpretation of the site as a whole is impossible without recording the dimensions and appearance of each context in both drawn and written forms. The aim of the drawn record is to complete as much of a three dimensional record of the site as is possible. The drawn record is primarily composed of two parts, plans – the record in the horizontal plane, and sections – the record in the vertical plane.

Guide to single context planning

This method is a development of conventional planning techniques. It sets out to make interpretation of site contexts easier. In principle, each SU should be recorded by its own plan before its removal. It should be defined before it is planned, and the process of documenting the SU includes the written record and the drawn, completed in conjunction with each other.

For each area there will be a series of overlaid record sheets on gridded polyester film (permatrace). Because these are overlain, they must record the trench or the context in exactly the same position each time.

A grid of pegs has been laid out at 5m intervals across the trenches according to cardinal direction using a Total Station. All planning is done according to this grid and it is key that the location of the grid pegs are marked on each plan. Producing a plan or a profile is an interpretive act, and this is an important part of recording the site. As the name of the style of planning suggests, in theory only one context (SU) should be planned on each piece of permatrace in the Villa Magna system. In practice, however, SUs judged to be in identical stratigraphic positions (a series of postholes, bonded walls and so on) may be planned on the same sheet. But overlapping SUs are never planned together. On the plan below, you will see the limits of other SUs drawn as reference, but note that there is only one SU planned here.

On the plan sheet various information must be filled in. Put your name and date on the lower left, indicate the scale (most often 1:50), and give the plan a number. Take the plan register from the area clipboard, write the name of the plan you are about to draw on the register, your name, and the date; Casale plans have numbers starting with 1000+; monastery plan numbers start with 2000+. Write the plan number on the permatrace. On the permatrace grid, mark and label the 5 m grid pegs with their coordinates (Eastings first, Northings second). Collect the equipment you need: 2 10m tapes, plumb bob, clips for the tapes, clips or tacks or tape for the permatrace, drawing board, pencil, eraser/rubber, etc. Sometimes it is helpful to take coloured thumb tacks and mark the edges of the SU you are drawing before starting to draw.

We draw features with two methods, offsets and triangulation. Offsets, which involve measurements from known features like walls or two grid pegs, can be used where the feature is small and close to the known line. Here a tape is stretched between the grid pegs or along the wall, and measurements at 90 degrees are taken with a hand tape. However, they are less accurate than triangulation, which is preferred for all important, large and irregular features, and absolutely necessary for structural features like postholes, whose center must always be triangulated (unless the point is taken with a Total Station). To triangulate one needs two tapes fixed to grid pegs, a plumb bob, a scale rule and a drawing compass. The supervisors will demonstrate this technique to anyone who does not know it.

All features should be drawn as accurately as possible. This means that stones or tile, though they are not measured in, should reflect the stones or tile in the feature. They should not be expressed by random jagged symbols. We call this eyeballing it, try to be as realistic as possible without spending too much time. In the case of tile patterns, skeletons and other drawing in which accuracy really counts a drawing grid may be used. If you are drawing a floor surface, locations of very particular objects should be marked with a triangle, their reduced level and an identifier (see Objects, below). The edges of an SU are represented as a continuous line, EXCEPT where the edge is the result of a cut, where the line is dashed.

Label the SU with its number, mark where you will take levels across the SU (a general rule would be to take levels at high point, low point, and somewhere in the middle. If your area has a running section, take the level along that too, at 50 cm. intervals.) Put the levels on the plan, marking the reduced levels of each spot height. (See Taking levels, below).
See here an example of a drawing of MON B I (2090).

Section drawing

Another useful record of excavation is the section. The purpose of a section is to show the thickness, or depth, or height of SUs and the relationship of SUs to each other in the vertical plane. Although the drawing of a section through every SU is a desirable aim, it is not always feasible. Sections should be drawn, however, to illustrate key stratigraphic relationships. Towards that end, running sections should be kept at fixed points within the trench, running NS or EW across a trench, or parallel to a range of rooms. Ask your supervisor where the section lines are, and take the levels across your context where needed.

It is important that the location of each end of every section is recorded on the section drawing and that section lines are shown on plans. During an excavation plans and sections should be checked to ensure the compatibility of the horizontal and vertical records. It is also very important to maintain clean baulks (vertical edges of your trenches). To aid in this, please do NOT sit on the edge of a trench, do NOT remove any bones or sticks or pottery protruding from the section baulk. When excavating, do be careful to keep your sections vertical (unless you have a very deep section in which case you might need to set back the section edges). A plumb bob is helpful when trying to keep the section straight.

To draw a section, take a piece of permatrace and fix it to your drawing board. Fill in the pertinent information at the bottom of a sheet (name, et cetera) and collect your equipment: 1 20m tape, 1 hand tape, nails, string, line level, plumb bob, clips for the tapes, clips or tacks or tape for the permatrace, drawing board, pencil, eraser/rubber, etc. Carefully secure a level datum across above the top of your section. If it is not at the zero for your area, note its difference on your plan. Secure a tape across the string, but remember that the string and not the tape is your baseline. Plot the top of each SU in your section using a tape, label it with a number. Eyeball in stones, pottery, and other components.

Taking levels

Levelling is the process by which vertical measurements can be related to an independent reference point and relative or absolute height values can be calculated. Levelling is used to record spot heights on plan and finds during excavations, to relate site levels to Ordinance Survey levels, et cetera.
This is a two-person instrument. One person holds a measuring rod at the point being recorded while the other sights through the instrument, takes the reading, does a simple calculation, then enters the final result on the context sheet, profile, or plan. There will be on-site training for the Dumpy level, because it is important that everyone know how to use them.

Set up

1. Put the tripod in a relatively level place, above the points to be measured, and (if possible) away from foot traffic.
2. Sometimes it helps to use a line level to make sure the top of the tripod is roughly level.
3. Mount the Dumpy level on the tripod. Avoid dropping it.
4. Adjust the leveling screws on the Dumpy level until the bubble is in the centre of the circle.
5. Place the measuring rod on a Zero (established for each trench at the beginning of the excavation) The zero for the monastery is the church doorstep, for the Casale it is the doorstep of the Granaio.
6. Looking through the Dumpy level, center the crosshairs on the measuring rod, and read the staff. This reading gives you the height of the instrument.
7. Write the height of the instrument onto a piece of masking tape stuck to the tripod.

Taking elevations

1. Place the measuring rod on the point in question. Make sure that there has been proper communication between the rod-holder and the person taking the reading—the rod-holder needs to know exactly where the base of the rod should be. Poor communication is the source of most errors.
2. Looking through the Dumpy level, center the crosshairs on the measuring rod and read the height.
3. Subtract this measurement from the instrument height. This gives you the height of the point being measured.
4. Write the result on the context sheet, profile, or plan. Be sure to add a minus sign for negative readings.

Things to remember

1. If the instrument is set up when you come to it, or if you have left it for some time before taking levels, check the instrument is still level before taking readings. If the bubble is slightly off-center, adjust the leveling screws without touching the tripod. If the bubble is completely off-center, someone has knocked the tripod, and you need to re-do the set up. Remove the tape showing that day’s instrument elevation, and replace it with one showing the new elevation.
2. If you knock the tripod, set it up again, and let everyone know that the elevation has changed.
3. When taking an elevation, never lean on the Dumpy level.
4. Think about the elevations you’re getting. If at the end of the day the readings are higher than those at the beginning of the day (“digging upward”), something’s gone seriously wrong. Cross-check your results occasionally to make sure that the elevations make sense.
5. Keep all your readings and calculations on the back of the scheda, and label each one, so that if there are any errors it is easy to go back and check the numbers.
6. Be careful when you’re carrying the instruments; they are easy to damage.