Scanning a large outdoor area

Scanning in large, feature-poor outdoor areas is one the most difficult scenarios for Hovermap. The key to a successful scan is to plan your mission path effectively. Start your mission in the center of the target area, or in the area with the most features, and then follow a path that avoids any large open spaces. Some examples of flight paths could be an outward spiral or a grid-type mission. Make sure that you close the loop, and that there is plenty of overlap between scans.

1. Start in the center of your area, or in the area with the most features, so that you can begin the process with a good quality scan.

2. If you are scanning a large area, you may need to break it up into smaller scans. If you do this, we recommend that you break it up into unique assets. Make sure that there is at least 20% overlap between each scan, as this helps Hovermap to more easily keep track of its position.

3. For each of these smaller scans, make sure that you close the loop as often as possible. Go to Scanning techniques for more information.

4. Give careful consideration to where you will place your GCPs. These will be extremely helpful when aligning each of your smaller scans should you choose to merge. Make sure that you always have at least two GCPs between overlapping scans.
   Note: This is not referring to Emesent's automated GCP system.

5. If particular areas are of high importance, consider performing additional walking scans so that the area is sufficiently targeted. These walking scans can then be merged with the flight data.

• Mapping mode: You can use Hovermap with third-party mission planning software by operating Hovermap as a passive payload. In this mode, Hovermap will have no control over the platform.

• Pilot Assist mode: Hovermap will provide you with collision avoidance protection from obstacles such as trees. If you decide to use Pilot Assist mode, it can be a bit more challenging to fly a regular pattern. But the benefit of this approach is that this mode is also highly adaptable to unforeseen conditions.

• Autonomous Waypoint mode: Using this mode can make it easy to scan your target area. However, you should keep in mind that Hovermap will always face forward, so you might want to take over control occasionally to focus on an area of interest.

Go to Understanding Hovermap for more information on choosing the best navigation method.

Step 5: Perform your mission

1. Perform your scan in accordance with your carefully planned mission path.

2. Fly as low and slow as possible. Keep below 40 m flight height, and keep your speed below 5 meters per second. Make sure that you stay 5 m to 10 m above the tallest obstacle for that particular flight.
   Note: The height you can successfully fly at varies, depending on your environment. In feature-poor environments, your maximum height will be significantly lower. Experiment with flight heights in similar environments before committing to a specific height.

3. Make sure that you focus specifically on your GCPs during the scan.

4. While scanning, check the live point cloud to ensure that your target area is covered sufficiently. Do this in the Hovermap App or the Waypoint UI (go to The Hovermap App section for more information). You can also do this by connecting to the Hovermap’s Wi-Fi, opening a web browser (on any laptop or Android device), and then navigating to hover.map:8082.

Step 6: Process your data

1. Process your scan data using the Emesent Aura Software. When processing, select the Standard profile for the first job.

2. If your results are not as desired, you can then change the processing parameters. For large outdoor areas, we recommend that you use either the Low Features or Forest profile.

3. To merge your data, start with the most accurate individual scan. This will ideally be the scan from the center of your target area. From there, you can align all your other scans to the central scan. By doing this, you will avoid accumulated error.