Map Fusion

Map Fusion automatically and seamlessly stitches point clouds across multiple scans and converts them into an absolute coordinate system:

• When valid control points or RTK data are available, it seamlessly stitches the point clouds of multiple projects.
• When absolute coordinate information is available, it converts the point cloud into an absolute coordinate system.
• It avoids the overlap-area layering that can occur from RTK or control point accuracy issues when global optimization is used alone.

Field Work

Basic Guidelines

For field operation guidelines, refer to the Acquire Point Cloud Data with Absolute Coordinate chapter.

Overlap Area Requirements

Applies to: all fusion modes.

Path overlap

• Adjacent maps must share a path overlap of a certain length.
• The recommended overlap length is 15–30 m, and no less than 15 m.

Scene selection

• Choose overlap areas with rich features.
• Avoid setting overlap areas in the following degraded scenes:
  • Open areas
  • Long corridors
  • Smooth tunnels
  • Other feature-poor environments

Control Point Fusion Requirements

Control points with absolute coordinates

• Ensure a scan overlap of > 15 m between adjacent projects.

Control points without absolute coordinates

• Ensure a scan overlap of > 15 m between adjacent projects.
• Effectively record control points within the overlap area.
• When marking the same control point in two projects, both of these must match:
  • Device position.
  • Control point name.

Minimum Requirements for Coordinate Conversion

Coordinate conversion is only possible when all of the following are met:

Map connectivity

• All maps are connected (via relative control points or continued scanning).

Number of absolute control points

• At least 3 absolute control points across all maps.
• Control points must not be arranged in a straight line.

Office Work: Data Processing

See the LixelStudio user manual for details.