Drone Mapping

Drone mapping surveys or drone topographic surveys have now come into their own. We can measure sites in a fraction of the time of conventional survey operations. That isn’t to say this technique is without limitations. As skilled land surveyors, we know the relative accuracies of data. We understand the limitations of drone technology. As a result, we can maintain precision across a project. While any drone pilot can make a map only a trained land surveyor has the depth of knowledge to deliver precise spatial data. We can map sites quicker than a conventional land survey takes and with better deliverables. As land surveyors, we know quality still counts when carrying out land surveys with drones. We apply this know-how throughout our drone mapping services.

For the ultimate service, we take an integrated approach to data gathering and can provide visually rich and accurate deliverables as 3d models.

Photogrammetry for Drone Mapping

Drones have brought about a renaissance in Photogrammetry. Photogrammetry is a subset of Remote Sensing where visible light is captured with a camera. Photogrammetry then uses image overlap between multiple images to create a model of the landscape or object.

The origins of Photogrammetry stretch back over 100 years. Photogrammetry, until recently, has been limited to large-scale airborne flights using aeroplanes and helicopters. Yet, Advances in drone technology and the photogrammetry software behind them have revolutionized survey work.

Overlapping photographs are used to calculate 3d points in a sparse point cloud, and then a dense point cloud before a 3d mesh model is created. The final step is to apply textures to the model.

Dense point cloud of a planning application site.

High-quality textured model of a planning application site

Once the model has been created orthographic images can be exported for use in GIS and CAD software. From this, we can extract a Digital Surface Model (DSM) and a Digital Terrain Model (DTM).

Street scene of photogrammetry model to show the planning application site in context to its surroundings or setting

We digitize the model to produce a drone topographic survey which is comparable to a traditional ground-based land survey. To ensure a clean accurate model it means we have to follow a process to ensure complete coverage to produce a quality drone map. Our drone mapping services follow land surveying principles and are of a higher quality than simple drone mapping you might get from a drone pilot who isn’t a land surveyor. This rigorous approach allows us to vary the Level of Detail (LoD) to match your needs, maintaining accuracy & precision where it counts.

AI is used to classify the model and point cloud data. Classification allows us to extract a bare-earth model or Digital Terrain Model. Classification also allows power lines, buildings and trees to be isolated from the data and processed separately.

LiDAR surveys have their own limitations but also some unique advantages. LiDAR makes many return measurements at various levels. Several hundred thousand points a second are measured using laser beams Effectively ‘peaking’ through the gaps in vegetation to measure the ground details below the canopy. This allows us to remove vegetation, revealing hidden ground details. We can then extract survey data in hard-to-reach areas with relative ease. Where required we can infill with traditional topographical survey equipment (total station, GPS, laser scanners etc.) to produce a drone topographic survey. Drone mapping is a game changer.

Drone Surveying DJI M300 drone with L1 lidar scanner

‘Seeing’ inaccessible places hidden by vegetation with Lidar data makes it a valuable data set. In this example, bunds can be seen underneath the tree canopy. Gathering this data by traditional means would be very time-consuming.

Drone mapping services

We are able to produce drone mapping surveys & models of ground survey-grade quality. We have a sound appreciation of data quality. Our skills as Land Surveyors, acquired with over 30 years of working in the trade, allow us to match the survey method to a client’s needs and specifications. For some projects, we can use the full range of methods and apply them to a project. We can combine photogrammetry data, Lidar data and ground survey data as required to produce a quality drone land survey or integrate the survey with a measured building survey for complete coverage of your project.

The most basic deliverable is a rectified and geo-referenced orthographic photograph of a project area. For construction monitoring/progression monitoring, this may be sufficient on its own. However, a drone land survey will take the 3d data created and convert that into a survey-grade topographical survey.

Drone mapping – choosing the right drone

Choosing the correct drone for the topographic survey required is important. The battery life, the camera type, wind resistance, flight height, ground sampling distance, the survey specification, and the site itself are all important considerations when choosing which drone to use on-site.

Having chosen the correct drone, using the correct payload to get optimal results for the drone topo. Accurate measurements can then be taken across the site or project of the correct precision to ensure you get the results you need.

We have a number of drones of various sizes and capabilities. Small drones can collect data for drone mapping in all the tightest places. Large drones with different payloads to collect data for drone mapping across small to large areas.

If you need reliable drone mapping services then contact us today to ask us for a drone mapping quote.