Your First Image Set
Shoot your first agriculture image set
Your First Image Set
To apply vegetation health indices (VARI or NDVI), you first need to capture multiple photos of your farm area of interest.
In a nutshell, the process is as follows:
- you execute a flight mission over the area of interest and your drone captures multiple individual photos covering 100 % of the farm area.
- You upload your images to our web platform
- You process your images and create a map (typically less than 5 mins)
- You apply either VARI (standard cameras) or NDVI (near infrared cameras) to detect crop health issues (in real time)
To make a successful mission and ensure that you capture high quality images, please check the minimum requirements below before you take off.
Minimum requirements and best practises:
To achieve satisfactory results we recommend to use at least a 12 MP camera. This is valid for both RGB and NIR cameras.
To be successfully stitched together, the individual photos of the farm area should overlap.
As a general rule: the higher the image overlap the easier it is to stitch the images and to create a high quality orthomosaic map.
Recommended: at least 70 % front overlap and at least 70 % side overlap of each image. To adjust the image overlap, please use the timelapse feature set at an appropriate interval.
Example: The DJI phantom camera has a Lens with a Field of View (FOV) 94°, 20 mm (35 mm format equivalent) f/2.8. Assuming a 4:3 aspect ratio, and if you fly at 120 meters altitude with 20 km/h, your camera should shoot an image at about every 8 or 9 seconds to achieve 70 % front overlap.
To achieve 70% side overlap, the distance between each leg of the flight should be 77 meters.
To be processed all of your images should be geotagged. This means that your camera (either RGB or NIR) should be able to associate a geographic location to each individual photo.
To be processed your images should be in JPEG format.
The GPS coordinates should be present in the EXIF metadata of the image file. Normally, commercial digital cameras embed automatically this technical data into the image file.
Focal length, sensor size and camera model should also be present in the metadata.
We recommend that you fly between 70 and 120 meters above the ground.
However, keep in mind that you can fly at any altitude depending on your preferences. The general principle is: greater altitude means that you’ll be able to capture a bigger surface area per image and ultimately cover more ground within one flight.
Also: the bigger the surface area per image, the better stitching results you’ll get because there will be more distinct features (such as crop rows, trees, tractor trails etc.) in each image. The stitching is basically a mathematical process that identifies these distinct features and matches them to create an orthomosaic map.
Finally, higher flight altitude could compensate for bigger image overlap (when you increase the image overlap, you reduce the ground area that you can cover within one flight).
Reminder: make sure to respect your local regulations as to the flight altitude.
It’s recommended that your drone controller has the ability to execute automatic missions. It’s normally possible to do this either with your native drone app or with a third-party software that communicates with your drone controller. For example, if you fly with a DJI drone you can use the Litchi App.
Having the ability to plan and execute automatic missions will let you capture a comprehensive set of images and get 100% coverage of the entire farming field without any “holes” while maintaining the same flight altitude and assuring that your images have sufficient front and side overlap.
Your images should be in “NADIR” direction (the direction in which gravity pulls). This means that your camera should be downward-facing and pointing vertically to the ground at all times.
Although not mandatory, we strongly recommend that you use a gimbal. In such case, you should apply the same logic: set your gimbal at -90 degrees.
Drone speed and vibration
Fast moving drones or vibration, could cause motion blur. To reduce the likelihood of this effect, you should either increase shutter speed or reduce drone speed. You could also remedy by increasing flight altitude.
Orthomosaic maps on demand:
You can stitch the individual photos together to create an orthomosaic map of the area. This is a paid feature.
To do that, just hit the button “request orthophoto” in map view to contact a company representative. We’ll walk you through the process, examine your data set and provide pricing.
The minimum requirements set out above apply also here. As a general principle, please keep in mind that the bigger the surface area per image, the better stitching results you’ll get because there will be more distinct features (such as crop rows, trees, tractor trails etc.) in each image.
The stitching is basically a mathematical process that identifies these distinct features and matches them to create an orthomosaic map.