Following on from the n4ce Golf Survey Case study, which used LiDAR, Aerial Photography and GNNS to carry out a golf course survey, this case study looks at the golf practice ground, to design a new teeing off area and chipping green. Here, we combined traditional GNNS with our own drone survey, to create visuals and quantities, that were then submitted to the decision makers at the golf club.
Part of the original survey was used, to give an overall view of the new design, as shown above. What we need to establish, are visuals and quantities for a new practice ground arrangement. The starting point was to carry out a survey of the existing practice area. We could, and did use the LiDAR survey previously mentioned, but this was supplemented with a GNNS survey, which confirmed that the levels were compatible.
Since AiC had recently purchased a drone, this was also used to generate up to date geo-referenced photography and check levels. Both a learning and very enjoyable experience!
The real problem with the existing practice ground is the restricted space, and the fact that the ground had a significant curvature. An elevated teeing box was proposed to raise the viewing area, so long drives could be seen landing! A new chipping area was also proposed, maximising the number of golfers using the practice ground at any one time.
Since low velocity range balls would be used on the practice ground, the maximum drive would be less than 200m. This positioned the elevated tee, leaving space for the chipping area, as identified below.
Preliminary Design – Tee Box
A 10m x 34m tee box outline was staked out on the ground and surveyed using control from the original survey. They then fell within the same OS coordinate system, ensuring that the correct model levels are used. A formal outline of the tee box and chipping green were made in a model dedicated CAD backcloth, as shown here. The borehole symbols indicate the position of the stakes. These positions were modified later during the design process.
A preliminary design was carried out based on these dimensions but on reflection, it was thought a 15m wide tee box would be better. This would provide for up to ten 3m wide driving bays and a 2m walkway along the back and side, as shown later.
The top level of the teeing box was set to 84m, to approximate the existing ground level at the southern east edge of the tee box. The top falls 10cm from front to back, to remove any standing surface water. The maximum height difference from the existing ground surface to the tee box at its northerly corner, at 1.3m.
The positioning of the tee box, with batters, had to allow a clearance from an existing tree line for green staff and their equipment, and the side slope should allow safe grass cutting. It was felt that a 1 in 4 batter would suffice.
Whilst only the corner points of the top surface were initially established, the string was densified to improve the model, especially when generating batter strings.
Cut and fill intercept batters were generated from the top surface to the existing ground, both at 1 in 4 and batter intercept strings calculated. A DTM was then formed using the top outline string and the batter intercept string.
This DTM was then used in volumes calculations to give the overall quantity of material in the raised tee box, which approximated 300 cubic metres as shown below. The footprint areas of cut and fill were also calculated and CSV files created from these strings for setting out.
The 3m driving bays were added to the model, together with the 2m walkway as shown below. Whilst 1.5m square artificial mats would be supplied, it was felt that space should be made to allow golfers to drive off grass ahead of the driving mat. The annotation shown here was added using CAD tools found in the dedicated CAD backcloth.
The proposed chipping green was designed to be used by several golfers at the same time, testing both bunker shots and chipping. A little artistic licence was used to create a chipping area with some character!
An outline feature string was sketched out and then used to generate a balanced volume using 1 in 1 batter slopes. A level putting surface was created with a cut balanced by fill. The northern area was in fill, whilst the southern area was in cut, as shown here. Banking was built up on the southern edge to redirect surface water away from the green.
An isopachyte model was generated to show cut and fill, and bunkers added to the model to complete the picture, as shown here.
To complete the picture, targets were created at 50yd intervals. The LiDAR data used in this survey comes in two formats. One with vegetation removed and another retaining vegetation, including trees. The latter was used to generate an overall visual impact of the new design.
Sections were also taken through the proposed design, as shown here, which was exaggerated vertically by x5, showing height differences between the new design and the existing ground.
A section was taken through the proposed tee box and chipping green, as shown here, with a 5x vertical magnification.
A long section was also taken through the proposed teeing box and the practice ground. A sight line 1.5m above the teeing box was created to show that there was a clear line of sight to the landing area for long drives.
Since many of the decision makers at the golf club have a non-technical background, visuals were created and posted for members to make comments. The new designs were approved at a committee meeting and work commences to put these designs into practice.