The Ground Sampling Distance (GSD) is the distance between two consecutive pixel centers measured on the ground. The bigger the value of the image GSD, the lower the spatial resolution of the image and the less visible details. The GSD is related to the flight height: the higher the altitude of the flight, the bigger the GSD value.
Example:
- A GSD of 5 cm means that one pixel in the image represents linearly 5 cm on the ground (5*5 = 25 square centimeters).
- A GSD of 10 m means that one pixel in the image represents linearly 10 m on the ground (10*10 = 100 square meters).
Note: Even when flying at a constant height, the images of a project may not have the same GSD. This is due to terrain elevation differences and changes in the angle of the camera while shooting. Since the orthomosaic is created using the 3D point cloud and the camera positions, an average GSD will be computed and used.
Information:
- How to select camera focal length and flight altitude considering the desired Ground Sampling Distance and terrain to map: How to select Camera Focal Length and Flight Altitude considering the desired Ground Sampling Distance and Terrain to map?.
- TOOLS - GSD Calculator: TOOLS - GSD calculator.
- Can Pix4Dmapper process images taken at different flight heights?: Can Pix4Dmapper process Images taken at different Flight Heights?.
Team Pix 3D, do we have a Three D block of GSD so I can place it dynamically under flight planning. means SW | DW as 3d like the one visible in Pix4D after the flight. i guess it will really help develop failsafe missions
Hi Pritpal,
If my understanding is correct you would like to have a visual display of the image footprint while planning a mission using Pix4Dcapture?
Note that the most important parameter when flying is the GSD which you can have an estimate while planning the mission with Pix4Dcapture. Also to process properly your data, the other important parameter to consider is the overlap which you can also set in Pix4Dcapture.
Best,
Hi,
How do I get the resolution of my pictures using the GSD (if that makes sense)? For example, I have a GSD of 3.5 cm/ pixel.
Hi Sara..................simple use the calculator
Hello, I would like to know, if the height of the terrain changes, what is the variation of the gsd allowed?
Hi Hernán
This should help: Can Pix4Dmapper process Images taken at different Flight Heights?