4.5 Control Point Marking During Scanning

Naming Convention

Point names are case-sensitive. The name you type in LixelGO at the marker must match the name in your coordinate CSV file exactly, character by character, including capitalization. There is no fuzzy matching, no autocorrection, and no warning at processing time if the names differ. If they do not match, that point is simply ignored.

Naming Rules

• Use short, distinctive names that you can type without error under field conditions
• Use only ASCII letters and digits. Avoid spaces, punctuation, accented characters, and special symbols
• Establish a consistent convention before going to site (project code + sequence number is a reliable pattern)
• Use the same exact name across every scan segment if the same physical location is being shared for Map Fusion

L2 Pro and K2 Workflow

For the L2 Pro and K2, marking a control point requires placing the device on the ground at the target position. The device must be stationary when the mark is recorded. The procedure is the same for both devices.

1. Walk Around the Sticker Before Placing the DeviceCircle the target sticker once or twice with the scanner active before placing it on the ground. This scans the sticker from multiple angles and gives LixelStudio the geometry it needs for automatic target detection during accuracy verification. Do not skip this step; placing the device immediately on a sticker that has not been scanned from any standing angle produces a poorly-covered target.
2. Set the Device Down Gently on the MarkerPlace the scanner on the sticker target slowly and steadily, centering it as accurately as possible over the marked position. Avoid any sudden contact with the ground; jarring the device at the moment of placement introduces positional error at that control point that cannot be corrected in post-processing.
3. Add the Control Point in LixelGOWhile the device is stationary on the target, open the control point interface in LixelGO and type the point name exactly as it appears in your coordinate CSV. Confirm the entry. Wait for the success confirmation before moving.
4. Lift the Device Slowly and Continue ScanningPick up the scanner slowly and steadily. Violent or sudden movement immediately after marking affects the accuracy of that point. After lifting, remain in the vicinity of the marker for a few seconds or circle it once to scan additional surrounding geometry before moving on.

PortalCam Workflow

The PortalCam control point procedure differs because the device is mounted on a tripod rather than placed directly on the ground. The requirements for app and firmware versions are specific: LCC Scan version 1.2.0_p1 or later and firmware version V3.2.3-20251104 or later are required for control point functionality.

1. Deploy the PortalCam on Its Tripod at the Control Point LocationSet up the tripod stably at the control point position. Choose locations with good ambient lighting, clear texture in the surrounding area, and unobstructed open space. Avoid corners, dark alcoves, and areas directly adjacent to mirrors or glass.
2. Add the Control Point in LCC ScanIn LCC Scan, open the control point marking interface and type the point name. Hold the device stationary for at least 5 seconds after submitting the mark. The extended hold time is a PortalCam-specific requirement that ensures sufficient scan data is collected at the stationary position.
3. Circle the Point After MarkingAfter the hold period, walk the PortalCam in a circle around the control point location to capture surrounding geometry from multiple angles. This produces a more complete point cloud around the marker and improves target detection reliability in LCC Studio.

Marking for RTK Accuracy Verification

When using RTK and verifying accuracy against target stickers, the marking procedure is different from GCP marking. For RTK accuracy verification, you do not need to place the device on the ground at the target. Walking around the sticker while scanning is sufficient to capture it for accuracy verification purposes. The device does not need to be stationary.

The sticker still needs to be scanned properly for LixelStudio's automatic target detection to work. Walk around it at close range, within 1.6 ft (0.5 m), and ensure it is clearly visible in the scan path before moving on.

Ending a Session After the Last Control Point

If the last action before ending the scan session is marking a control point, do not end the recording immediately. Wait at least 15 seconds after the control point confirmation before stopping the session. Ending too quickly after a mark means the point carries insufficient scan data around it; LixelStudio may not recognize it as a valid control point.

The 15-second rule is a minimum. After the last control point, if the project permits, continue scanning for 20 to 30 seconds and walk a small loop nearby before ending. This provides the scan with additional closing geometry and ensures the last marked point has full coverage in the dataset.