3D models and point clouds specifications

The Globhe standards for 3D models and point clouds

The Globhe standards will be applied if others are not specified in your order.

3D models and point clouds, even if substantially different, are both digital representations of real-world objects and environments captured using drones. These data sets are obtained using specialized sensors, such as optical/RGB cameras or LiDAR (Light Detection and Ranging) scanners, mounted on the drones. 3D models and point clouds from drones have numerous applications across industries, including assets management, engineering, surveying, urban planning, and environmental monitoring, among the others. They enable clients to visualize, analyze, and extract valuable information from the captured data, facilitating tasks such as accurate measurements, 3D reconstructions, integrity assessments, volume calculations, terrain modeling, and change detection.

3D models are three-dimensional digital representations of physical objects or structures. They provide a detailed and accurate depiction of the shape, size, and geometry of the captured subjects. Drones equipped with high-resolution cameras can capture multiple images from different angles (both nadir (top-down) and oblique (sides)), which are then processed using photogrammetry techniques to create textured 3D models.

Point clouds, on the other hand, are dense collections of millions of 3D points representing the surface of objects or the environment. Drones equipped with LiDAR sensors emit laser beams that measure the distance to various points on the ground, vegetation, buildings, assets, or any other objects within the drone's range. These distance measurements are then combined to form a point cloud, where each point contains information about its spatial coordinates and potentially additional attributes, such as color or intensity.

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Deliverable specifications

Fleight height

Definition: the altitude or elevation at which a drone operates during an aerial mission or flight.

Globhe standard: 60 meters AGL*, in line with national and local regulations in place.

*Above Ground Level = the altitude or vertical distance between the drone's current position and the Earth's surface.

Preferably using the terrain follow mode*, where possible.

*Terrain follow mode = flight mode available on certain drones that allows them to automatically adjust their altitude and maintain a consistent distance above the ground or terrain below. When the terrain follow mode is engaged, the drone utilizes various sensors and algorithms to detect and track the ground's elevation. It uses available terrain models as a reference to continuously adjusts its flight altitude and compensate for changes in the terrain, such as hills, valleys, or uneven surfaces. By following the terrain contours, the drone can capture consistent and precise data, while enhancing the safety and efficiency of drone operations.

Speed

Definition: the rate at which the drone can travel through the air or move from one location to another. It is a measure of how quickly the drone can cover a certain distance within a given period of time. The speed of a drone is typically expressed in terms of a linear velocity, often measured in meters per second (m/s). The speed of a drone can vary depending on various factors, including its design, size, weight, propulsion system, flight mode, and external factors (such as wind speed and direction).

Globhe standard: 3 - 5 m/s and adjusted to meet the technical requirements.

Image overlap (3D models)

Definition: the degree of redundancy or overlap between consecutive images captured during a drone flight mission. It is typically expressed as the percentage (%) of overlap between adjacent images along (front overlap) and perpendicular (side overlap) to the flight direction. Image overlap is needed to ensure the accuracy and quality of the resulting drone data. The overlap allows for better stitching and alignment of the images during post-processing (photogrammetry), enabling the creation of seamless 3D models.

Globhe standard: 75% front overlap, 70% side overlap.

Point density

Definition: the number of LiDAR points or data points within a specific area or volume of space. It quantifies how densely the LiDAR sensor has sampled the surface or objects in the surveyed area. Higher point density generally leads to more detailed and accurate representations of the surveyed area. It allows for the capture of fine-scale features and terrain variations. Point density can also influence the accuracy of derived products, such as digital elevation models (DEMs) and 3D models.

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Globhe standard: a minimum of 20 points/m² .

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Coordinate Reference System (CRS)

Definition: standardized system for defining and interpreting geographic coordinates, allowing for accurate and consistent positioning of features on the Earth's surface. In the context of drone data and mapping, the CRS plays a vital role in establishing a common reference point for geospatial data captured by drones. It consists of three key elements: coordinate system, map projection, and datum. The coordinate system specifies how locations are defined on a two- or three-dimensional plane using coordinate values. The map projection converts the curved surface of the Earth into a flat surface, facilitating the representation of spatial data on maps or digital screens. The datum provides a reference frame for measuring and aligning coordinates to the Earth's surface. There are various types of CRSs used in geospatial applications, including geographic coordinate systems (e.g., latitude and longitude), projected coordinate systems (e.g., Universal Transverse Mercator), and local coordinate systems (e.g., State Plane Coordinate System). Each CRS has its own set of properties, units of measurement, and accuracy characteristics.

Globhe standard: WGS 84 / (EPSG: 4326) / Meters.

Data format

Globhe standard: LAS (.las) or OBJ (.obj) for 3D models and point clouds.

Drone models and sensors

Globhe relies on a wide range of commercial drone models available through our Crowddroners, including but not limited to multirotors (i.e. quadcopters, hexacopter, octocopters) and fixed-wing, mounted with every sort of sensor as payload*.

*Payload = the additional equipment or devices that are carried or attached to a drone in order to perform specific functions or tasks. These payloads can vary depending on the purpose and capabilities of the drone. The most common drone payloads are RGB cameras for aerial photography or videography, sensors for data collection (such as thermal, multispectral imaging, or LiDAR sensors), and specialized equipment for tasks like seedlings, crop spraying, or search and rescue operations.

If the drone model and/or sensor are not selected, the GLOBHE team will choose the suitable drone needed to meet technical requirements, also based on availability.