GCPs in Drone Mapping

GCPs (Ground Control Points)

• GCPs are essential for drone mapping and consist of two parts: Target and GPS
• The Target is a physical point on the ground, and the GPS is the device that captures the location
• GCPs are used for Georeferencing, which is the process of assigning coordinates to images taken by a drone

GCP Targets

• GCP targets can be purchased or made, but it's recommended to use the Drone U landing pads, which are scientifically proven to create a more highly discernible Center Point
• The Drone U landing pads are numbered, making it easy to identify them, and they are organized, so when you shoot 0, 1, 2, 3, 4, 5, you need to find pad 1, 2, 3, 4, 5 easily in the software
• A minimum of five GCP targets are required, and if you include two checkpoints, that means seven targets in total

Case for GCP Targets

• A Pelican case is recommended to store and transport the GCP targets, but you don't need a case as heavy as that
• You can roll up the pads simply, and they don't require a case, especially if you're not traveling on an airplane

RTK GPS (Real-Time Kinematic GPS)

• RTK GPS is a type of GPS that provides highly precise subcentimeter accuracy
• It requires an internet connection and access to an RTN (Real-Time Network) to provide corrections to the unit
• RTK GPS is fast, precise, and efficient, but it's also the most expensive and requires the most infrastructure to work
• It's ideal for urban environments with wide-ranging broadband access or internet access

PPK GPS (Post-Processed Kinematic GPS)

• PPK GPS is a type of GPS that corrects the data after the fact based on where the points were shot
• Arrow points are PPK GPS that correct the data after the fact
• Arrow points are easy to use, but they have a high reprojection error, especially when flying above 200 feet
• PPK GPS is a good solution for rural areas with limited internet access

Scale Constraints

• Scale constraints are used as a backup when GPS is not available
• Scale constraints can be a tape measure, surveying rod, or laser measure
• A scale constraint should be at least 300 to 500 times GSD (Ground Sample Distance)
• Having a scale constraint as a backup is essential to ensure accuracy and avoid errors

GCPs (Ground Control Points)

• Consist of two parts: Target and GPS, essential for drone mapping
• Used for Georeferencing, assigning coordinates to drone-taken images

GCP Targets

• Can be purchased or made, but Drone U landing pads are scientifically proven to provide a more discernible Center Point
• Drone U landing pads are numbered for easy identification and organized for efficient software use
• A minimum of 5 GCP targets are required, with 2 checkpoints making a total of 7 targets

RTK GPS (Real-Time Kinematic GPS)

• Provides highly precise subcentimeter accuracy
• Requires internet connection and access to an RTN (Real-Time Network) for corrections
• Fast, precise, and efficient, but also expensive and requires significant infrastructure
• Ideal for urban environments with wide-ranging broadband access

PPK GPS (Post-Processed Kinematic GPS)

• Corrects data after the fact based on shot locations
• Arrow points are PPK GPS with post-fact corrections
• Easy to use, but high reprojection error above 200 feet
• Suitable for rural areas with limited internet access

Scale Constraints

• Used as a backup when GPS is unavailable
• Examples include tape measure, surveying rod, or laser measure
• Should be at least 300 to 500 times GSD (Ground Sample Distance)
• Essential backup for ensuring accuracy and avoiding errors

Learn about Ground Control Points (GCPs) in drone mapping, their components, and their role in Georeferencing. Understand how to create and use GCP targets for accurate image assignment.