It wasn’t so long ago that mapping was a hugely expensive activity carried out by government agencies and, of course, Google! By using expensive equipment and having access to satellites and official records, these organisations provided the source material for virtually all public and commercial maps.
Jump to 2022 and commercial drones and sensors have now become readily available, meaning mapping and surveying is cheaper, faster and more accurate than ever. Drone surveying and mapping even lets you reduce risk and improve mid-point visibility for any project.
Drone surveying and mapping can be up to 75% quicker than traditional methods
How a drone survey works
Traditional land survey techniques involve taking multiple distance and angle measurements using a total station to generate topographical maps, boundary lines or many other types of plots. Drone surveying instead starts with a single photograph, much like you’d take with a mobile phone. Like your phone, the GPS chip in the drone allows that picture to be tied to the latitude and longitude coordinate system, potentially providing absolute positioning errors of a few centimetres.
2D mapping
One aerial image is not going to make a map, so to make a larger survey the drone can fly along a predefined course, at a set height, and take multiple photos autonomously. The resulting images are stitched together, creating what is called an “orthomosaic”. The orthomosaic can be combined with the GPS coordinate data to give you a geo-referenced image that shows incredible detail in the form of a two-dimensional map.
3D mapping
Being able to create a 3D model of an asset, whether it is a telecoms tower, a building, or a bridge, for example, allows you to accurately measure and plan any development or maintenance. To create a 3D model you simply need to create a data set of images, as we do for 2D mapping, but this time you need to capture images from all angles. These images, once they have been processed, can generate 3D models that are sometimes called digital surface models or digital elevation models, that provide not only flat imagery but the topography and elevation data as well.
Saving time and money with drone surveying
Compared with regular surveying, drone mapping and aerial surveys can be done in a fraction of the time and cost, but with more detail. It has been shown that a job taking 3-4 days previously could be accomplished in just a few hours with an enterprise level drone and the correct camera or sensor.
By gathering all the image data from the air, you can avoid ground obstacles and complete the job with fewer crew members and less overall risk. This is especially important in areas where the terrain prevents traditional support equipment from being safely deployed, or when working at height where the risk of falls are high.
What can drone surveying and mapping be used for?
So, I think we can agree that drones can survey land or assets faster and safer than more traditional methods but why would you, as a business, want to carry out surveys and mapping in the first place? What’s it in for you? Here are three typical use cases.
Construction
The use of drones in construction really does start at the start and end at the end.
What better way to scope a development site than from above where you can accurately plot boundary lines, identify unseen hazards, create meaningful plans and more. Or maybe you need to precisely calculate the amount of material remaining on a building site before purchasing a new load, resulting in zero-waste. You can also keep a track of progress at regular intervals by taking advantage of pre-defined flight paths and data collection points to be able to repeat the same task exactly, over and over and over.
This is all achievable using drones with the right sensors and post-processing software.
Agriculture
The return on investment that a farm generates is directly linked to the health of the crops that are being grown. If disease takes over a crop and wipes out an entire field that will have a devastating effect on productivity. Similarly, if the crop is not getting the nutrients that it needs at the right time then the crop yield might also be lower than its potential.
Drones, equipped with multispectral sensors, can analyse the physical structure of any vegetation and quickly identify any health issues that need to be addressed before the crop is lost – this is called an NDVI (normalized difference vegetation index) survey. The image is returned in multiple colours, each one depicting the condition of the plant and indicating what the issues might be.
Roof inspections
Why put somebody in harms way by sending them up onto a roof to inspect its condition? If you follow all health and safety guidelines you might erect scaffolding, or install edge protection barriers, or maybe even use ropes or cranes to get the view you need. All of which comes at a cost and takes time and a LOT of risk assessment!
Using a drone you can quickly and safely create a full map of the roof in high definition that can be analysed, zoomed into, annotated, measured and assessed, all from the safety of the ground.
In addition to this we are able to use radiometric thermal imaging sensors to create heat maps of a roof. This can easily identify any heat loss issues that could be caused by damaged material beneath the surface of the roof and it will also highlight any areas of water ingress. With this data you are able to pin-point any required repairs without the need to replace more than is required.
Residential roof inspections can also easily diagnose issues such as damaged chimneys, read more about that in our article – Can a drone inspection help find a leak?
Why not choose drones as a valuable tool for your next project?
I hope this article has helped to explain a little bit about how we can use drones to carry out mapping and surveying and also some of the benefits that can be realised in your industry today. In my opinion, drone surveying and mapping is revolutionising many industries and will become the ‘go-to’ solution for the majority of our inspection needs, particularly when working at height or where we need data that just isn’t captured by the human eye.
So, are drones the future of mapping and surveys? We think so.
If you would like to talk to Skyball Visuals about your project please do contact us.