Maptalker

Below is the basic process we have been using to fly and process UAV imagery. 1) Set up control points using a DGPS. These can be targets placed out before flight or opportunistic points which can be gathered before or after the flight. Control points are distributed throughout the entire site and x y accuracy is roughly 2-15 cm depending on soaking time and conditions in the field. 2) Fly the UAV in a grid pattern to cover the study area with ~ 80-90% overlap in imagery. Maximum area covered in one flight is roughly 1.5 km x 1.5 km at 300 meter flight elevation. 3) Take the imagery back to the lab and process it. A number of programs are used such as Adobe Lightroom to reduce image distortion and Autostitch to mosaic the images together. 4) Find the DGPS control points in the imagery and 5) georeference to the DGPS points gathered in the field – transformation type may need to be assessed per image basis, but spline has been the most successful so far. 6) A complete georeferenced orthophoto is complete and ready for use in ecosystem mapping, object based image classification, or overlaid with your field data points as a basemap.

Basic timetable breakdown for each step for a single flight (1.5 km x 1.5 km swath):

1)  Field control points ~ 1 hour

2)  Flight ~ 20 minutes

3)  Processing ~ 3 hours

4&5)  Georeferencing ~ 1 hour