Introduction
drone technology for mapping and surveying has eased the process of creating maps for construction.Photogrammetry and LiDAR are the two methods by which construction maps are created using drones. Both these methods with the assistance of data processing software give mapping out.
Maps prepared by drone mapping
The types of maps that can be prepared with the help of drone mapping are:
1. Orthomosaic maps
2. Digital Elevation Models (DEM)
3. Digital Surface Models (DSM)
4. Digital Terrain Model (DTM)
5. Contour line maps
6. 3D point clouds
7. 3D textured maps
1. Orthomosaic maps
Orthomosaic map is an aerial view map of a site with a uniform scale to be used to measure true distances as it accurately represents the earth’s surface. Many aerial view photos of an area are connected and orthorectified to form an accurate map; this map is termed an orthomosaic map.
High-resolution camera drones are used to capture the most realistic and most accurate images to be stitched together to create an orthomosaic map. Orthomosaic maps provide a very accurate and most realistic view and hence are mostly preferred against other traditionally drawn maps.
2. Digital Elevation Models(DEM)
Digital elevation model is a 3D representation of elevated terrain, of a surface of a planet, moon, or asteroid where instead of actual representation colours codes are used to indicate elevation differences. Globally, digitally elevated models are referred to as a distinct global grid.
DEMs are used often in geographic information systems, which are most commonly used to produce digital relief maps.
3. Digital Surface Model (DSM) and Digital Terrain Model (DTM)
DSM (Digital Surface Model) covers both natural and man-made attributes of the environment.
A DTM (Digital Terrain Model) typically adds characteristics of the natural terrain, such as rivers and ridges and other pure earth features and provides a bare earth surface model. A Digital Terrain Model may be induced to generate a Digital Elevation Model, but not vice versa.
4. Contour line maps
To determine the elevation of terrain or landmass contour lines are drawn on maps. Contour lines are imaginary lines depicted on maps that join equally elevated land. Contour line maps provide an easy and clear depiction of peaks, valleys, and slopes and the direction of flow of rivers and ridges can also be determined by contour lines.
Professionals like surveyors, foresters, engineers, miners, geologists, and hunters use contour line maps.
5. 3D Points Clouds
Web Cloud forming a densified point cloud from the images captured by a drone is a 3D point cloud. Thousands of geometric coordinate points form 3D cloud points. Each point gives geospatial (x,y,z) and colour data. With a combination of all coordinates, a 3D model is built. With the gradual increase in the number of coordinates, the model becomes denser.
6. 3D Textured Mesh
3D texture mesh is nothing but updated 3D point clouds. Along with points it also produces edges, faces, vertices, and texture of the area from images captured by drone. It makes visual inspection clear and ideal for monitoring project progress.
Conclusion
Drone mapping in construction enhances efficiency, accuracy, and safety by providing real-time data for site analysis, progress tracking, and quality control, ultimately optimizing project management and decision-making processes.