What is UAV Mapping?

An unmanned Aerial Vehicle (UAV), commonly known as a drone is an aircraft that flies without a human pilot, crew or passengers on board.

UAV is part of an Unmanned Aircraft System (UAS), which also include a ground-based controller and a communications system with the UAV.

UAVs were created in the twentieth century for military duties that were too dull, dirty or dangerous for people and by the twenty-first century, they had become indispensable assets to most forces.

Aerial photography, product deliveries, agriculture, surveillance, infrastructure inspections and drone racing are among these applications. 



Land surveying is a difficult and complex task as the world continues to meet the problem of land scarcity and population growth.

Land Surveyors have long since mapped territories utilizing a range of traditional methods and tools such as manned flights, satellite data, robotic total stations, GPS receivers, retroreflectors, 3D scanners, handheld tablets, digital levels, subsurface locators, GIS, and surveying software.

Today, drones or UAVs are now widely used for land surveying purposes and it is possible to carry out topographic surveys of the same quality as the highly accurate measurements acquired by traditional methods may now be completed in a fraction of the time.

This significantly minimizes the expense of site surveys as well as the workload of field professionals. 


Conventional method in land surveying

Downward-facing sensors such as RGB or multispectral cameras and LiDAR payloads are used to collect aerial data for UAV mapping.

The ground is captured several times from different angles during a UAV survey with an RGB camera and each image is tagged with specific coordinates.

Photogrammetry software can build geo-referenced orthomosaic, elevation models or 3D models of the project area by using this information.

These maps may also be used to extract data like very precise distances or volumetric measurements.

UAV can fly at a far lower height than piloted aircraft or satellite imaging and at the same time it can help to allow the collection of high-resolution, high-accuracy data faster, less expensive and independent of atmospheric factors such as cloud cover.  

What is the Usage of UAV in Surveying?

Below is a list of the usage of UAV mapping:

1. Land Surveying or Cartography

In areas where low-quality, old, or no data are available, UAV mapping can help to produce high-resolution orthomosaic and comprehensive 3D models.

As a result, even in complicated or difficult to access areas, high accuracy cadastral maps may be created fast and efficiently.


Cadastral map overlay in orthophoto

Surveyors can also extract elements like signs, curbs, road markings, fire hydrants and drains from the orthophoto.

These same photos may generate incredibly precise elevation models, contour lines and break lines, as well as 3D reconstructions of land sites or structures after post-processing with photogrammetry software. 

2. Land Management and Development

UAV captured aerial photos significantly speed up and simplify topographic surveys for land management and planning.

This holds true for site scouting, allotment planning and design, as well as final construction of roads, buildings and utilities.

The orthophoto also serves as the basis for comprehensive topographic models of the site for pre-construction engineering studies.

Engineers may instantly begin working from a 3D model using the produced data which can be exported to any CAD or BIM software. 

Images may be captured at regular intervals and superimposed on the original designs to analyse if the building activity is progressing according to plan specifications, as data gathering by drones is easily reproducible at a cheap cost. 

 
Aerial survey during construction activity in progress 

3. Precise Measurements

i. Stockpile Volumetric Measurements

Volumetric measurements can also be obtained from the same photos using 3D mapping software.

This quick and low-cost method of volume measuring is especially useful for calculating inventories in mines and quarries for inventory and monitoring.

Surveyors can gather many more topographic data points with a drone, resulting in more precise volume measurements.

They can also do it in a far safer manner than if they had to physically collect data by travelling up and down a stockpile.

Drones will collect data from above, so activities on the ground will not be disrupted.

Because of the quick acquisition time, a site snapshot may be captured at any given time. 


Stockpile volumetric calculations and measurements

ii. Slope Monitoring

It is feasible to obtain slope measurements from DTMs and DSMs generated by drone photography using automated GIS analysis.

The locations can be categorised and utilised for slope monitoring, including landslide mitigation and prevention, based on the steepness of the ground's surface.

It is feasible to identify variations in earth movement and quantify its velocity using orthomosaics taken at various time periods.

This information can be used to anticipate landslides and protect roads, trains, and bridges from harm.


Slope monitoring data from the UAV data acquisition

UAV allow for more extensive data collection than traditional monitoring systems, which rely on sensors positioned at particular spots.

Drones with PPK capabilities, which do not need the establishment of several GCPs, are ideal for this application, as these places are frequently difficult to reach or even dangerous.

4. Urban Planning

The growth of more crowded and complicated metropolitan regions necessitates detail and extensive planning, which are time-consuming and costly data collection.

Urban planners can collect massive volumes of up-to-date data in a short amount of time and with significantly fewer employees by using UAVs.

Planners can use the orthophotos created in this way to assess the current social and environmental circumstances of the places and consider the impact of various scenarios.

Buildings may also be readily overlaid onto their surroundings using 3D models and will provide planners and other users with an immersive experience, especially for a complex development project.

Cast shadows and outlooks/views may also be analysed and visualised using 3D models. 



UAV solution for urban planning

What are the Advantages of Using UAVs in Surveying?

Below is a list of the advantages of the usage of UAV for surveying and mapping:

a. Reduce Time Spent Collecting Data And Survey Cost

Using a UAV to collect topographic data is up to five times faster than using land-based methods and requires less manpower.

Land Surveyor can save time by using PPK geo-tagging since the surveyor no longer needs to place as many GCPs.

In the end, a surveyor can deliver the survey data sooner and at a lesser cost.

b. Provide Accurate And Exhaustive Data

Total stations only measure individual points.

A single drone flight generates hundreds of measurements that may be represented in a variety of ways such as orthophoto mosaic, point clouds, DTM, DSM, contour lines, etc. Each pixel on the final map or each point on the 3D model comprises 3D geodata.

c. Mapping Of Otherwise Inaccessible Areas

An aerial mapping UAV can take off and fly practically anywhere. Surveyors are no longer limited by inaccessible areas, dangerous steep slopes or harsh terrain unsuitable for traditional measuring tools and do not need to close down the highway or train tracks.

The Deliverables and Output from UAV in Surveying?

Below is a list of the deliverables from UAV mapping: