Drone Surveying and Mapping

Drone Surveying and Mapping

Our drones can obtain high resolution imagery for surveying and mapping of a range of environments. Our drones are programmable to fly pre-set routes guided by GPS, allowing imagery to be captured accurately along defined transects or specified locations within the survey site. Drone surveying can be used as a standalone technology or in addition to traditional surveying technologies and/or traditional aerial imagery techniques.

The use of drone technology can enable accurate measurement of features or areas that cannot be safely accessed, or which would involve excessive time and cost due to the size of the area. See our Drone Services Page for more information on the advantages of drone technology.

Throughout his career as an environmental scientist, our head pilot Rylan gained extensive experience in the design and implementation of monitoring programs, gathering and analysis of survey data, and building 3D models using captured data.

Orthomosaics

Opterra uses professional image processing software for the rectification, assembly, and correction of aerial images taken from our drone – (also referred to as a UAV or RPA). The resulting orthomosaic is a beautiful geo-referenced image that can be analysed in any GIS or remote sensing software. We can cover a range of site sizes depending on the terrain, weather, and desired image resolution (Ground Sample Distance).

For centimetre precision, we recommend using ground control points to improve the relative accuracy of the project. In general terms and without ground control points, our accuracy is 1-2 times the ground sampling distance (GSD) horizontally and 2-3 times the GSD vertically.

Aerial Imagery

Opterra uses the DJI Inspire for capturing raw data for our drone surveying project. Images are captured with a 12-Megapixel camera in RGB. If required, the camera can be replaced with a near-infrared band camera. The on-board GPS allows for the images to be geo-referenced.

Photogrammetric applications

Photogrammetry is the science of making measurements from photographs. With the geo-referenced images taken with our drones, it is possible to identify millions of tie points and calculate their positions. Point clouds and digital surface models (DSMs) with a sampling distance of 2-4 times that of the RGB images can be generated from the high resolution of the aerial images collected

Images can be processed to create a 3D point cloud – a set of points defined by X, Y, and Z coordinates. This information allows for the generation of:

  • Digital Surface Model (DSM)
  • Digital Elevation Model (DEM)
  • Triangulated Mesh Model

The above outputs provide information about the site which can then be used for the following:

  • Surface analysis
  • Volume measurements
  • Contour line generation
  • Breakline generation
  • Animation
  • Visualisation
  • 3D printing

Volumetric Calculations

Once all the images are collected, processed and geo-referenced, the resulting high resolution DEM can be used to calculate the volume of specific objects. Because of the high density of elevation points collected using aerial imagery, a good accuracy can be achieved for the volume calculation.

Using this information, we can calculate the following:

  • Cut volumes
  • Fill volumes
  • 3D surfaces and slope angles

Thermographic drone surveying

Thermographic drone surveying is performed using a camera that can capture images in the Infrared spectrum. The infrared scan will show the thermal reading of an object as either hot or cold. Infrared thermography is non-destructive, non-intrusive, non-contact mapping of thermal patterns on the surface of objects.

Thermographic surveys can help you see heat, thermal losses and potential electrical equipment failures before they become issues. This can assist to manage equipment costs, increase fire safety, and look for energy reduction opportunities.

Thermographic surveys are particularly valuable on large, complex 24/7 operations, where electrical equipment cannot be switched off without major disruptions to operations. Isolation of the electrical supply becomes increasingly difficult where continuity of supply is essential for operations. Our drone can capture thermal imagery while equipment is in operation without compromising the safety of operators.

The camera is developed by FLIR, a world-leader in the design and manufacture of thermal imaging cameras. It provides high-sensitivity (50mK) infrared scanning at up to 640/30 fps. This sensitivity provides accurate temperature measurements. The camera reveals details invisible to the naked eye by making subtle differences in temperature visible. This new view of the world can reveal damage to equipment or buildings, the location of lost people and much more.

This information can assist in the following applications:

  • Powerline inspection
  • Solar panel inspection
  • Search and Rescue
  • Precision Agriculture
  • Fire fighting

Multispectral imagery

A multispectral image is one that captures image data at specific frequencies across the electromagnetic spectrum. The colours we see in light are defined by the wavelength of that light. Plants absorb and reflect light differently depending on this wavelength. Plants typically absorb blue light and red light, while reflecting some green light. They also reflect a much larger amount of near-infrared (NIR) light, which is not visible to the human eye but is visible to multispectral cameras.

Opterra uses a powerful sensor with four narrowband filters (Green, Red, Red-Edge and Near Infrared) with a 16 MP RGB camera for easy digital scouting. The Irradiance sensor and integrated GPS make it an accurate and calibrated tool whereby imagery can be collected at resolutions measured in centimetres per pixel.

There are hundreds of applications in the fields of agriculture, ecology, oil and gas, oceanography and atmospheric studies where multispectral remote sensing can be used to better understand the world we live in. For example:

  • Data captured on a frequent basis enables growers and agronomists to map the health and vigor of crops today as well as observe changes in crop health over time.
  • Refine fertilisation by detecting nutrient deficiency symptoms
  • Optimise pesticide input through early detection of biotic stress
  • Control crop irrigation by identifying areas where water stress is suspected
  • Estimate crop yield by processing and exploiting agronomic indices

Live Broadcast

Opterra can broadcast everything live directly to large-screen displays, YouTube audiences and standard TV channels. This technology allows us meet the requirements of professional broadcasting at high frame rates and HD clarity at up to 1080p/60fps or broadcast standard output of 720p/59.94fps and 1080i/50fps. This allows imagery to be observed and analysed in real-time.

Temporal Resolution

A major benefit of data obtained from drone surveying, over traditional ground, manned aircraft or satellites, is the temporal resolution that can be achieved. The fast set-up of drones allows images to be captured daily or even multiple times a day.

Search and Rescue

Opterra offers volunteer search and rescue (SAR) services to search for missing persons. Our primary mission is to offer and provide drone services for ongoing Search and Rescue operations at no cost to the SAR organisation or to the family. In addition, we want to create increased awareness about the benefits of drone technologies.

Aerial search for lost persons is extremely costly with traditional fixed wing aircraft and helicopters. Small, highly manoeuvrable drones may aid and support search efforts in many situations for a fraction of the cost in risk, and resources.

Once a subject of interest is located, the exact location can be relayed back to the ground crew. Our drone can search an extensive area in minutes that might take an entire group of ground personnel to cover in hours. In additional, our thermal infrared imaging camera can detect heat to assist in finding missing persons particularly at night.

drone surveying for volume estimations