Aerial Survey and Mapping

Aerial mapping and surveying has been around for long. It’s useful across industries, including infrastructure development, agriculture, and forestry. Technological advances such as the development of better sensors and the integration of AI-powered analysis have resulted in even better aerial survey results. Three-dimensional representations of territory and infrastructure can be acquired. Point clouds can be used for mathematical calculations and analysis.

Currently, a wide range of sensors can be used for aerial photography, resulting in richer results. For example, with the use of near-infrared Imagery coupled with RGB sensors, vegetation can be reliably analyzed. Such a multi-sensory approach enables the use of the Normalized Difference Vegetation Index for such use cases as assessing the health of crops.

An aerial survey camera can also be equipped with a thermal sensor, enabling applications such as the assessment of roofs to direct maintenance efforts.

Perhaps the most useful development in aerial survey and mapping is the development of high-quality sensors. Currently, there are medium format cameras which have resolutions as high as 100MP. With a large format aerial solution, images with a resolution as high as 280MP can be captured.

The use of drones in aerial mapping and survey is becoming a standard. For example, in aerial 3D mapping of sections in cities, drones have proven invaluable. Some drones have payloads consisting of 50-MP cameras. Such high-quality sensors, coupled with the fact that drones can fly much lower than helicopters and planes, ensures that the images captured by drones are of sufficiently high quality to allow advanced analysis, such as that powered by machine learning and artificial intelligence algorithms.

Forms of Data Acquired Through Aerial Surveys

Depending on the purpose of aerial survey, the resulting data can be represented in a variety of formats, including contour lines, digital surface models, digital terrain models, point clouds, 3D maps, and orthophotos.

Orthophotos  

These are simply two-dimensional representations of the terrain under survey. They are usually geo-referenced.

Typically, multiple aerial photos are taken and combined to provide highly-accurate two-dimensional information. Such photos are calibrated to topography standards. They can be used for measurement and planning.

Digital Surface Models

Such models are used to represent the terrain of a territory and are usually color coded. The color coding is used to indicate altitudes, with one end of the RGB spectrum representing the lowest points and the other end representing the highest.

They are used to make advanced calculations, such as cut and fill, and are useful for planning.

Digital surface models can either be two-dimensional or three-dimensional, depending on the file format used. They are usually used to represent everything on a terrain, from buildings to trees.

Digital terrain modes, on the other hand, usually represent only the raw ground data about a terrain, that is, the altitude values of different points.

Contour Lines 

A contour line file consists of the three-dimensional representation of a terrain expressed through vectorized lines that are made at regular intervals. Such files are usually generated from digital surface and terrain models.

Point Clouds and 3D Models 

A point cloud is a representation of a terrain using a multitude of points. Each point has three-dimensional data.

Point clouds are instrumental in the calculation of volumes, distances, and areas, as well as the determination of percentage of slope. Point clouds also offer an accurate depiction of terrains since they can be colorized.

3D models are three-dimensional representations of terrain. Unlike point clouds, 3D models are continuous and are perfect for visualization rather than calculations.

Index Maps 

These are representations of terrains according to indices such as the Normalized Difference Vegetation Index. Index maps come in handy in the analysis of vegetation.

For example, in agriculture, index maps can give insight into the health of crops. Plants reflect various types of light differently, for example depending on their chlorophyll content. The analysis of an index map can help a farmer identify crops which don’t have enough chlorophyll and which may be diseased.

Aerial 3D Mapping

With an aerial survey camera, it’s easy to acquire a 3D map of territory. Aerial 3D mapping can be done through manned aircraft such as helicopters and planes or through unmanned aerial vehicles.

Data can be acquired through photogrammetry, where multiple photos are taken and later stitched together using special software, or through Light Detection and Ranging (LiDAR) sensors.

The use of a large format aerial solution on manned planes is useful when capturing data on large tracts of territory. With the high-resolution that comes with large format solutions, the manned plane can fly high and still capture high-quality images.

To use LiDAR, a drone equipped with a LiDAR sensor is all that’s required.

Drones and Agriculture 

Drones are becoming crucial in agriculture, especially now that amid an increasing world population, producing enough food has become a challenge. They are being used directly in food production. For example, they are an important tool in precision agriculture.

In addition, drones have become instrumental in other areas related to agriculture. For example, phenotyping with UAVs or drones is growing in popularity. Phenotyping is a field of science that involves the study of the effects of genotype and the environment on crops. It aims to promote the development of desirable characteristics in crops.

The use of drones in areas such as phenotyping comes with an array of advantages. For starters, it’s affordable, both in terms of costs and the effort made. The use of manned aircraft is subject to more stringent regulations than the use of drones. Drones can also cover relatively large areas, which makes them more suitable than traditional methods of survey such as ground teams.

By aiding precision agriculture, drones are revolutionizing the production of food. Precision agriculture promotes the efficient use of resources, including fertilizer and water. To achieve it, data is crucial and drones come in handy in the data collection about farms.

With drones, index maps of farms can be acquired and used to determine which parts of a farm need watering. With this information, rather than watering the whole farm blindly, water can be used more judiciously.

At the same time, the information acquired through drones can be used to analyze the history of produce to determine infertile areas which most need fertilizer.