Here are several recommendations we can provide to aid you in generating and evaluating maps with WingtraOne.
Original data quality
The quality of the data collected by WingtraOne is a very important element in obtaining an accurate map. Image quality, light condition, and flight path overlap are the three factors that most affect the quality of the original data.
High resolution images are essential to ensure a successful stitching (orthophoto generation). All of our cameras were thoroughly chosen to guarantee high quality images. Especially for projects with high requirements, it is advisable to use the first-rate Sony RX1R II sensor. For more details about our diverse range of sensor options, check out our camera page.
The default camera settings that we provide cover a large range of light conditions. Nevertheless, it is advisable to check the images after the first flight to make sure the images are not underexposed or overexposed. The orthomosaic generation favors images with many distinctive features which are constant over all images. Therefore, flying on a bright but cloudy day would be ideal to prevent shadowing. Shadows darken areas and reduce the visibility of features. Additionally, shadows result in appearance changes between images, as the position of the sun changes during the flight.
The default overlap (front and side) parameters are set to 70 percent, which is a good compromise between stitching robustness and data volume. Increasing the overlaps improves the stitching quality but at the same time increases the processing time, including geotagging. The side overlap is additionally linked to the flight duration as the number of rows increases. On the other side, the front overlap is only affecting the number of images.
Flight imagery can be geotagged (Non-PPK Geotagging, PPK Geotagging) after the flight. Non-PPK geotags are always in the coordinate system WGS84 with egm96 as height reference. Without PPK the geotagging accuracy of WingtraOne aerial images is in the range of a few meters. In cases where you use WingtraOne PPK, the coordinate system depends on the choice of the base station coordinates. For more information on coordinate systems of PPK processed aerial data please refer to the Coordinate Systems for WingtraOne PPK article. In optimal case, when flying with PPK an absolute geotagging accuracy down to 1 cm can be achieved. With both options PPK and non-PPK, the resulting products have a high relative accuracy, which allows to measure lengths or volumes accurately.
For projects, where high absolute accuracy is required, you can either use WingtraOne PPK or you can add ground control points (GCPs). When flying with a WingtraOne without PPK, we recommend to use at least five GCPs and three check points. Distinctive and stable features on the ground or additionally added marks can be used. The points should be measured accurately and placed in a way that each one is visible on multiple images. Most post-processing software allow the import of GCP coordinates and provides an interface to mark them in the images. Make sure to specify the coordinate system and height system correctly.