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Topo surveys – a blended approach: by Baseline Surveys Ltd

Thursday 1 December 2022

In this article, I will be explaining to you how blended modern topographic survey methodologies can benefit your project, writes Paudie Barry.

Significant topo survey innovations by Baseline Surveys over past 32 years

As you may already know…

In 1993 Baseline Surveys along with GPS Ireland were the first surveyors in Ireland to innovate combining GPS and total station methodology to survey Mallow golf course. Today, almost 30 years later, this is still the mainstream method of topographic surveying across the world.

In 2013 Baseline Surveys Ltd was the first company in the world to publish a white paper proving that UAVs (drones) were accurate enough to be used for topographic survey data extraction according to ASPRS Standards.

In 2014 Baseline Surveys Ltd was the runner-up in the innovation section of the Irish Aviation Awards for our pioneering work on experimenting with drone technology for the purpose of topographic surveying.

Since 2015, we have been quietly blending 3D tripod based laser scanning point cloud data with drone survey 3D point cloud data to produce more informative topo surveys with more contextual geographic information so Engineers and Architects derive a more informed design for planning applications.

Apart from being the most innovative survey company in Ireland, we are also the longest established surveying company in Munster.

A blended survey methodolgy

Various survey methods are excellent at surveying certain features, but not all. GPS is great for picking up discreet detail under open skies, but it is slow and cannot measure indoors or under tree canopy. A total station is even slower, but is more accurate than GPS and can survey indoors and under trees with ease. As mentioned above the total station / GPS combination has been the mainstream method of surveying since around 1995.

Drones are superfast at surveying; a drone can survey a 30-acre site in 10 minutes to an accuracy of 1 or 2 cm, which is similar to GPS. Its limitation is that it cannot penetrate vegetation, not even grass. It should be noted that the levels from a drone on a field represent the top of the grass, as opposed to the topsoil.

The Drone’s survey strengths are being able to survey horizontal or nearly flat hard surfaces, such as roofs, car parks, lawns, earthworks and road surfaces very rapidly. It’s also great for guaranteeing completeness, because the under laying aerial imagery, beneath the topo, will very quickly highlight what is missing from the survey in CAD. The Drone’s weakness is in surveying vertical faces such as building facades, walls and fences. This is where a terrestrial 3D laser scanning comes in handy.

A 3D Laser scanner will scan everything visible within 360 degrees from its tripod position within a few minutes to an accuracy of 1mm. Its strength is being able to survey vertical features quickly and accurately, such as tree trunks, building facades, walls, fences, poles, signs etc. Its weakness is in surveying flat horizontal features and it takes time complete multiple set ups.

3d laser scanner data compliments aerial drone data perfectly well as the laser scanner is suited to picking up vertical features and the drone is great at picking up horizontal features. Discrete and critical features such as service covers and floor levels are surveyed traditionally using a GPS or a total station.

Experience has taught us that a fully blended approach fusing the data from drones, 3D laser scanning, total stations and tilt sensing GPS to create topographic surveys is more cost efficient, more complete and more accurate than current traditional survey methods.

An engineering approach to land surveying

Rather than a one size fits all approach, our attitude at Baseline Surveys is that all projects and sites are different, we use our engineering background to make sure the survey deliverables are fully matched to each individual projects requirements. We use our vast experience to fully consider all downstream architectural, planning, engineering design and construction requirements for your project.

Being an engineer is an advantage because I fully understand your how your design depends on the quality of my survey data.

About Baseline Survey Ltd

Paudie Barry, company owner is a qualified civil engineer, has a higher diploma in GIS and 33 years of experience as a land surveyor and setting out engineer on large and small residential, commercial and civil engineering projects.

My 33 years of experience coupled with our blended approach using advanced survey equipment can provide you with robust topographic surveys which are competitively priced.