Area Survey
Last updated
Last updated
A survey is a mission plan that contains at least one survey pattern; a grid flight path over an arbitrary polygonal area, flown at a particular altitude and using a specified camera or camera settings.
The survey area is a polygon or circle marked out on the map (shaded in green above). The numbered green circular markers indicate the points where the vehicle enters and exits the pattern.
An Survey Editor item in the mission item list on the right is used to set the grid angle, spacing, and other properties, and to specify appropriate camera settings for creating geotagged images.
This topic shows how to create a survey mission, and the various settings that can be configured in the editor.
The easiest way to define a survey is to use the Plan view > Pattern > Survey tool from the Plan Tools.
This creates a template for a simple end-to-end survey mission for the current vehicle type. Often all the user has to do is define the survey area (any items that require configuration are shown with a red border in the mission item list).
If a more complex mission is needed, the basic mission can be extended by adding other items before the return item.
To create a survey mission:
Open the Plan View and select the Pattern button and then the Survey pattern.
Check that the Mission Start item settings are correct for the planned survey. In particular that the altitude (Waypoint altitude) is high enough to avoid obstacles when travelling to the survey.
From the Mission Editor select the Mission tab to edit the Survey.\
With the survey area selector you can change the shape(basic, circular and trace) of the survey area.
Basic: Create a polygon starting from a rectangle. The filled circles (vertices) and center can be moved where needed (using the map). New vertices can be created by selecting the markers between existing vertices and then moved.
Circular: The filled circles in the centre and on the circumference can be moved on the map to change the circle's position and size.
Trace: Trace around the shape of the target region. The filled circles can be moved on the map while tracing (you cannot move the center point or create new vertices)
Select the Done Tracing button to stop tracing and display the Polygon Tools.
Load: Load region definition from a KML or SHP file.
Select the End button editor to choose the action to execute the end of the meeting.
Hold: The vehicle will hover at its current position and altitude.
Land: The vehicle is landing at its current position and altitude.
Return to Launch: It creates a path back to the mission take-off point.
The Survey Editor is used to configure Camera and Grid settings, and also to save and re-use Presets. The bin icon can be used to delete the whole item.
Set the camera first, before configuring the grid (camera capabilities affects the grid settings).
Camera triggering during a survey depends on the capabilities and orientation of the camera, the survey altitude, required image resolution, grid density and trigger distance.
Users can select a predefined camera (recommended), enter the details for a custom camera, or manually enter the altitude and grid characteristics.
Use a predefined or custom camera were possible, as this allows the survey grid to be automatically recalculated, trading off desired image overlap, image resolution and survey altitude.
Using a predefined/known camera allows automatic calculation (and recalculation) of an optimal survey grid pattern based on desired image overlap, image resolution and survey altitude.
Camera Selector
Select the camera from the list.
Landscape/Portrait
Camera orientation relative to the "normal" orientation of the vehicle. This is optional and will only appear for cameras that have asymmetric sensors, and hence can be mounted in different orientations
The Custom Camera option specifies the settings for a “custom” camera, allowing users to benefit from dynamic recalculation of the grid even if their camera is not predefined.
The custom settings are the same as for a predefined camera, but include additional fields for the camera definition.
Camera Selector
Custom Camera
Landscape/Portrait
Camera orientation relative to the "normal" orientation of the vehicle. This is optional and will only appear for cameras that have asymmetric sensors, and hence can be mounted in different orientations
Sensor Width/Height
Camera image sensor size (mm).
Image Width/Height
Camera image resolution (pixels).
Focal length
Camera focal length (mm).
Users can also choose Manual (no camera specs) as shown below. The Grid settings will then include options to set the survey altitude, trigger interval and grid spacing.
This approach is not as convenient as using camera settings, as a change to any value (or the camera) means that the other settings must be recalculated manually.
Camera Selector
Manual (no camera specs)
Overlap
Overlap between each image capture. This can be configured separately for when flying along grid lines (Front Lap) or across them (Side Lap).
Altitude
Survey altitude. The Ground Res field is dynamically updated with the resolution required for entered altitude.
Ground Res
Ground resolution for each image. The Altitude field is dynamically updated with minimum value to achieve the entered resolution
For a manual camera:
If if any of these settings need to change, then they may all need to be manually recalculated.
Altitude
Altitude to fly the whole grid.
Trigger Distance
Distance over ground between each camera shot.
Spacing
Distance between adjacent grid (flight path) lines across the survey area.
The Transects section is used for grid settings that are independent of the camera. Changes in the settings are reflected in the map.
Angle
The angle of the grid lines (degrees), relative to North.
Turnaround dist
Additional distance added outside the survey area for vehicle to turn around.
Rotate Entry Point
Button toggles (swaps) the survey entry and exit points.
Options
Checkbox options for:
Hover and capture image: Hover to capture images (multicopter only).
Refly at 90 degree offset: Refly the whole mission at 90° offset.
Images in turnarounds: Take images when turning/outside the grid.
Relative altitude: Specify that the grid is releative to home (or AMSL)
Terrain Following makes the vehicle maintain a constant height relative to the ground throughout the survey (by default, a flying vehicle will follow the survey path at a fixed altitude). This is recommended when the terrain height varies a lot within the survey area.
Terrain following uses terrain heights queried from AirMap servers.
Vehicle follows terrain
Check to enable terrain following (and display the following options).
Tolerance
The accepted deviation in altitude from the target altitude.
Max Climb Rate
Maximum climb rate when following terrain.
Max Descent Rate
Maximum descent rate when following terrain.
The Statistics section shows the calculated survey area, photo interval, photo spacing and planned photo count and resolution.
The Presets section allows surveys to re-use commonly specified camera and grid settings.
Survey presets are saved in the plan file and can be reloaded onto the current ground station (only). If loaded onto another ground station result will be unpredictable.
Presets (list)
Selection list of user-created saved presets. Can bue used to select a preset to delete or apply.
Save Settings As New Preset
Saves the current settings as a named preset.
Delete Preset
Delete the currently selected preset.
Apply Preset
Apply currently selected preset to survey.
To save the current set of presets:
Select the Save Settings As Preset option. This will display the Save Preset dialog (on the right)
Enter a Preset Name.
Select Save.
The preset is then saved and added to the P_reset_ list.
Deleting Presets
Select the preset in the Presets list.
Select Delete Preset.
