Measure a Scan

The same tools as LiDAR photos: Single, Multi, Height, Angle and Area (Measure on LiDAR Photos and Video). Tap points on the scan's surface; every leg shows its length. Up is the scan's true up, so Height and Angle always work. On Thermal, each point also shows its temperature, and Save adds them to the note. Each bar reads Save, tools, Clear: Save keeps the readout as a note on the scan's station (Save Measurements and Notes); the eraser clears.

Tap the compass button for tools made for scans. Taps always land on a surface, so tools that shoot from the middle of the passage work that out from the spot you tap.

• Shot: two points give distance, bearing and inclination, like a survey book. Bearing comes from the scan's anchor; a scan with no anchor shows distance and inclination only.
• Clearance: tap the floor for the height straight up, or a wall for the width straight across.
• Section: tap the floor or a wall to cut the passage across your view and see its width, height and area.
• Drop: look into a pit and tap its edge for the depth straight down.
• LRUD: tap the floor for left, right, up and down from the middle of the passage.
• Splay: tap the floor for 6, 12, 18 or 24 splays from mid-height; tap the splay button again to change the count. Splays that hit nothing aren't drawn.

When a tool can't find what it needs, it says so: Nothing across from here (Clearance), No section here, look along the passage, not straight down (Section), Landed on the ledge, tap closer to the edge or No bottom found below this edge (Drop), No splay hit the scan from here (Splay). Survey tools respect a slice.

Tap Slice (the three panels), pick X, Y or Z and drag the two handles: only the part between them shows, with the cut outlined in red, and the volume between the cuts is worked out when you lift your finger.

Y slices floor to ceiling; X and Z are the scan's own axes, not compass directions. The volume says approx. when the cut crosses holes in the scan. Switch to the Ruler and the slice stays (the button shows a red ring), so you can measure across the cut. The eraser on the slice bar clears every cut and goes back to the whole scan.

The slider moves in 1 cm steps and the readout gives the range, thickness and volume (for example 0.80 to 2.00 m, 1.20 m thick, 8.6 m³). Cut on more than one axis to crop a box: tap an axis to choose which one the slider moves; a ring marks an axis with a cut, and pressing and holding an axis clears just that cut. Measure taps only land on the part still shown. Save keeps the slice readout as a note.

When a scan stops, SpeleoMap measures left, right, up and down at its start and end stations, plus extra wall shots called splays. A direction with no wall in range stays blank, never zero. Choose how many splays in Scanning settings. To add your own shots at any station, use Splay in the Drop Station menu (Splays and LRUD).

LiDAR and the camera make heat. If the phone shows a heat warning, give it a break between long scans; cool rock makes a good heatsink. SpeleoMap only stops a scan on its own if the phone gets critically hot.

For walls past the scan or a quick number later, LiDAR photos and video measure too: see Measure on LiDAR Photos and Video.