How to Survey a Field for Landforming Design

Last Updated: 07 October 2021

When a survey is performed, it creates a survey file for the field that contains a collection of data points.  Each point represents a specific latitude and longitude or Easting and Northing position within the field for which an elevation value is stored.

The data collected can be valuable to create informational maps.  Any maps created from this data is only as good as the quality of the data that creates it. In order to create quality maps from your field survey data, be sure to perform your field survey to the highest quality.  As a start, please observe the following guidelines as a minimum for performing a field survey.

  1. Use a RTK GPS receiver with a local base station within 1.6km or 1 mile for the highest accuracy and quality survey data. Using an inappropriate differential correction for collecting elevation data leads to inaccurate maps which leads to increased earthworks and earthworks imbalances.

  2. Mark a Master Benchmark to record a known position that you can find again and put the earthmoving blade on later. A concrete pad is best. At the very least, mark the sides of the survey vehicle inline with the GPS antenna using two pegs.

  3. Make the first pass on the exterior field boundary, when collecting survey data, to ensure sufficient data around the perimeter of the field for the design surface to extend to. OptiSurface Designer will extrapolate (extend) the design surface a little outside the defined survey boundary. This extrapolation distance could be 1m (3ft) in some places around the boundary and further in other places eg. 10m or 30ft, depending where the calculation grid falls.  

  4. Conduct a thorough survey by driving up and down the field on approximately the following swath spacing:

    • Fields with significant elevation changes and slopes — swath spacing of 7.5—15 m (25—50 ft.) is recommended.
    • Flatter fields — a swath spacing of 15 m (50 ft.) is recommended.
    • Flat to precision leveled ground — a swath spacing of 15—30 m (50—100 ft.)  Do not exceed 50 m (100 ft.) swath spacing for surveying purposes.

  5. The recording distance between the survey points as you drive along the tracks should be approximately 1 second or 5 m (15 ft). There's no need to stop at every point, just continue driving.  At about 15 kph (~10 mph) recording every second you get around 5 m spacing.  If it is a lot smaller than (eg 1 m) then the number of survey points can become large and get slower for the software to handle and process for fields larger than 100ha (250ac).

  6. Ensure that the entire field has been covered. Do not skip parts of the field because they are inaccessible due to wet or muddy conditions; you are in a hurry; you think you do not have time to finish properly. This has a negative impact on the quality of your maps generated from your collected data. It is important to cover the entire field.

  7. It is also a good idea to survey the bottom of existing ditches and large depressions so that the terrain shape is correctly recreated in the design software.  Utilizing parallel tracking with straight track can cause the user to miss areas of interest for surveying, for example the bottom of a main ditch which can have an obvious width and depth.  Driving along the shoulder (top off batter) of large ditches can also be worthwhile to better define the shape of the topography.
Here is an image example of a good survey.

Feedback and Knowledge Base