Are your images geo-tagged?

If you can send us images that already have the latitude and longitude in the EXIF metadata, then life is simple. We’d like to have altitude in there as well if that’s possible. Many cameras have built-in GPSs but our experience is that they don’t refresh fast enough to get accurate location data. Your aircraft is probably traveling around 15 m/s, so a one-second GPS refresh delay results in a big error in the ground location. Back to the top.

Do you need a geo-referenced mosaic?

Geo-referencing allows programs like Google Earth or QGIS to place your stitched mosaic in the correct place on the earth. This is a requirement for precision agriculture or surveying. However, if your needs are only to see a visual aerial image then perhaps you don’t need geo-referencing. There will be no absolute distance scales on a non-georeferenced mosaic. Back to the top.

Are you using a 3D Robotics flight controller?

Field Extractor, our custom client-side software package, is optimized for 3D Robotics hardware and software. If you use 3DR then the process of getting images to us becomes largely automated. But if not there are still ways to handle the process. Back to the top.

Does your camera have a GPS?

If you have a camera like the Canon S100 with a built-in GPS, then you can use the GPS to accurately set the camera clock so that it perfectly syncs with the flight log clock. Be sure to set your camera up so the GPS updates the clock. The default setting on most of these cameras is to have the GPS turned off. Back to the top.

Take a photo of the GCS screen to sync the clocks.

If your camera does not have a GPS, there is still a way to sync the camera clock and the flight log clock. It’s a bit more work but not too bad. Shortly before you mount the camera into your plane, take a picture of the ground control station (GCS) screen, including the on-screen clock in the photo. With this photo, Agribotix techs can look at the EXIF timestamp of the photo and compare it to the screen clock in the photo. That gives us a time offset, which allows the synchronization. Do this before every mission because these clocks drift a bit. Back to the top.

Can you create a KML file from your flight log?

A KML file is a Google Earth XML-format file that includes the plane’s trajectory and altitude. Check with the supplier of your ground control station software to see if it allows creation of KML files. Back to the top.

Geo-tag your images with exiftool.

Check this blog post for instructions on using exiftool to insert the lat/lon/altitude into the EXIF photo metadata. Back to the top.