LiDAR Laser Scanning
LiDAR measures distance to a target using laser beams. Measure Australia's LiDAR laser scanning produces over 1.4 million ground points per second. This data is survey grade with an RMSE of approximately 25/35mm. A 3D point cloud model of the subject area is rapidly produced in real time from this data. This is currently the most detailed and accurate method of creating digital terrain models, which is something photogrammetry is unable to do. The major advantage of LiDAR is the ability to remove vegetation layers from data allowing accurate ground surface models to be created. Learn more about LiDAR: /lidar-laser-scanning-the-next-frontier-of-drones/
Photogrammetry is a well tested solution for 3D modelling. Multiple overlapping photos of the ground are taken as the aircraft flies along a flight path and then the photos are stitched to create a 3D model. Absolute accuracy is improved using ground control points. Photogrammetry is the most accessible option for 3D mapping available, due to its low cost nature.
An orthophotograph is an ultra high resolution composite image made up of a range of individual images. It is used to measure true distances, because it is an accurate representation for natural distortion. Each pixel in an orthophoto represents a true distance on the ground, known as ground sampling distance (GSD). A 1-centimeter GSD would equal 1 centimetre on the ground. Orthophotography is used when clients have a large asset or land which needs a to-scale representation, such as a roof of a large scale roof.
A multispectral image contains multiple wavelength bands across the electromagnetic spectrum. This is used in agriculture for assessing crop health, water retention, and other nutrient related readings. It allows farmers to manage crops, soil, fertilisation and irrigation more effectively and efficiently. Multispectral imagery can identify pests, disease and weeds among other things. It is also used in conservation and rehabilitation by providing data on soil fertility and detecting nutrient deficiencies.