2D & 3D Drawing Improvements in SonarWiz

With the release of SonarWiz 7.5, Chesapeake introduced a drawing cache mechanism designed to allow for compact storage of, and quick access to, large bathymetric point clouds for display within the 3D viewer. This cache allows for much faster loading and drawing of large surveys by varying the level of detail shown to match the point of view, data loaded, and resources available.

Left: Recursive subdivision of a cube into octants. Right: The corresponding octree.


For SonarWiz 7.6, the drawing cache enhancements have been applied to the 2D plan view display, greatly improving drawing performance there as well. Previously, SonarWiz would draw bathymetry on the plan view by iterating through nearly the full set of data, regardless of zoom level, resulting in significant unnecessary work. Now, based on plan view resolution, data size, and user preferences, SonarWiz will adaptively read and draw only the data necessary.

In addition to drawing performance, use of the draw cache for plan view drawing allows for lower overall memory usage. In typical projects, SonarWiz will often use half or less of the memory used in prior versions.
The drawing cache in version 7.5 was built after a bathy merge process, and always built in full. 

In 7.6, the cache is incrementally updated after bathy editing, and updates are restricted to the areas changed, making this a much faster process overall. For large projects, the time between editing in the swath or area editors and seeing the results in the 3D and 2D views has been reduced in many cases from minutes to seconds.

Left: Plan view of bathymetry data represented using octrees. Right: 3D representation of bathymetry divided into octree nodes.

Drawing quality is improved in a couple of ways as well, both in the 3D viewer and in the 2D plan view. Better control over point sizes and level of detail is available, allowing you to favor drawing speed while working at the project overview level, but optimize for rendering quality for final output. In the plan view display, overdraw is better controlled,taking into account the point of view, resulting in less jarring visible discontinuity at swath intersections.

Users with large bathy projects will notice the biggest improvements from these changes; roughly speaking, the larger the project, the larger the performance benefits.

Jonathan Fleetwood, Development