1 : 31680 This drawing covers the counties of Gloucestershire, Oxfordshire and Wiltshire, with their boundaries indicated by pecked lines. The Roman road to Bath is tinted yellow to highlight it as a major communication route. A dotted line leading from Sapperton indicates the Sapperton Tunnel, which was opened in 1789. Linked to the Thames and Severn Canal, it was, at that time, the longest tunnel in England. The Sapperton Tunnel enabled boats carry coal cheaply to Cirencester from mines in the north and west. Several trigonometrical points are marked by dots within circles. These were points from which the surveyor took angular measurements to determine the relative locations of prominent features of the landscape. Metcalf, Edward B.
1 : 31680 This drawing covers part of the Thames Valley in the counties of Buckinghamshire, Berkshire and Oxfordshire. The plan is oriented to the east, with a compass depicted at middle right. Symbols distinguish woodland, heathland, arable enclosed land and formal parkland. Brushstroke interlining indicates relief and hills. The River Thames is depicted in the lower part of the sheet, meandering through Oxfordshire between Oxford and Wallingford. Stanley, William
1 : 31680 In the top right hand corner of the drawing, a red cross marks Chipping Norton Church. This was a base used by the draughtsman for orientation purposes. In 1816, it became obligatory to record archaeological sites on the plans. Here ancient camps are marked at Farmington and near Charlton Abbots. The words "TP Gate" appear on several roads, notably at Wincombe towards the top, indicating a turnpike gate. The accurate and precise record these drawings provide of the road network sets them apart from earlier county maps. Stanley, William
1 : 31680 This finished plan is attributable to Robert Dawson (1771-1860). The attribution rests on his distinctive portrayal of relief. A dark wash is used for the lowland areas followed by bands of lighter colour, graduating to almost colourless at the top of hills - a technique that produces a strongly three-domensional effect. Black-ink numbers, clearly visible on the high spots, indicate the relative height of the hills: Hill 8 being higher than Hill 5. This method of notating contour, combined with brushwork interlining ('hachuring') drawn to indicate the steepness of relief, precedes the official introduction of contouring on Ordnance Survey maps in 1839-40. Rows of small neat trees depicting orchards proliferate around the Vale of Gloucester, at the top left of this map. Dawson, Robert
1 : 31680 This plan of the Vale of Gloucester is indicative of the draughtman's convention of "relative command": the indication of relative heights of hills by numbers; hill 3 being higher than hill 2, for example. Brushwork interlining ('hachuring') and ink washes further depict relief. Pencil rays intersect across the map, evidence of measurements taken by the surveyor between fixed triangulation points. Archaeological details, such as those at Bredon Hill (at the top right of the plan), are documented even though this did not become obligatory until 1816. The rivers Severn and Leadon and part of the Hereford and Gloucester Canal are described at the bottom left of the map, with Tewkesbury situated centrally at the confluence of the Severn and Upper Avon Rivers. Dawson, Robert