METHOD STATEMENT FOR TOPOGRAPHICAL SURVEYS

Plan Control

A minimum of two survey stations are established using GPS+GLONASS from the Leica SmartNET service and marked with MAG or other suitable nails in hard surfaces. Multiple observations are taken with a minimum of 45 minutes between observations.

Further site control points (stations) are established as necessary by closed loop traverse.

The maximum error between survey control stations would not exceed 1 part in 20,000 for distances exceeding 200m. For shorter distances the maximum error would not exceed ±10mm.

Level Control

Height control is established by closed double-run levelling using either a convenient OS bench mark, precise levelling point or the value of one of the survey stations observed with static GPS.

The height difference between any two survey stations would not be in error by greater than: ±12 x √k mm where k is the distance in kilometres between the points being considered, or ±5mm, whichever is the greater.

Detail Observations

All survey observations are to be made with a Leica TS13 Reflectorless Total Station, Leica Viva GNSS GS08 NetRover other instruments available to Lincolnshire Surveys that have a current calibration certificate issued by an authorised Leica service engineer.

Details recorded generally include:

• Building outlines at ground level with ridge and eaves levels noted if required.
• Boundary features with type and levels of top noted.
• Hard detail including roads, kerbs, edgings, channels, tracks, walls, steps, and changes in surface materials etc. suitably annotated.
• Service covers, gullies and the like correctly sized and orientated with cover levels. Invert level may be recorded if required.
• Street furniture including, lamp standards, telecom & other poles, traffic lights, post boxes, telephone boxes and road signs etc.
• Overhead detail including service cables
• Trees greater than 0.2m dia at 1.50m above GL with trunk diameter and average spread and height noted. True canopy lines are recorded if required.
• Hedges and outlines of significant shrubs with height annotation.
• Tops and bottoms of banks.
• Invert of open ditches/watercourses.
• Spot heights on nominal grid as appropriate to the site or client requirements and at any significant changes in level.
• Contours at 0.25m vertical interval or less if required.

Detail is recorded to the accuracy dependant on the survey scale required.

Downloading and Processing

Data is downloaded into Applications in CADD n4ce professional survey software for processing.

Presentation

Drawings are delivered by email in PDF and AutoCAD DWG format.