Moving & Comparing

After selecting countries or regions, reposition them to compare true area at different latitudes and contexts.

Basic Movement

• Drag any selected country to a new location
• True area remains constant while visual shape adjusts with projection
• Compare how perception changes when moved near poles vs equator

Dragging a country to a different latitude

Rotation

• Hold R and drag to rotate around the shape’s center
• Release R to exit rotation mode

Rotating a selected country with the R key

Deletion

• Press Delete / Backspace to remove selected countries

Copy & Paste

• Press Ctrl/Cmd + C to copy the selected country
• Press Ctrl/Cmd + V to paste at the same position

Copying and pasting a selected country

Map Navigation

Left Mouse Button

• Drag empty space to pan the map

Right Mouse Button

• Always pans (ignores shape selection) for precise navigation

Mouse Wheel

• Scroll to zoom in/out (works in both 2D and 3D)

Touch (Mobile & Tablet)

• Tap: Select
• Drag: Move selected
• Two‑finger drag: Pan map
• Pinch: Zoom
• Tap empty space: Deselect

Multi-Select (Group Comparisons)

Multi‑select helps answer: "How big is Europe compared to Africa?" or "Could multiple countries fit inside another?"

Selecting multiple countries with a drag box

How to Multi-Select

1. Click the Select button to enable selection mode
2. Drag a rectangle around countries to select multiple at once
3. Hold Shift and click on countries to add/remove individual countries
4. Drag any selected country to move the entire group together

Press Delete / Backspace to remove all selected countries.

Holonomy System

Holonomy explains why shapes appear to rotate when moved over a sphere. TrueSize applies authentic spherical transport so orientation changes naturally.

What is Holonomy?

When you move an object along a curved surface (Earth), its orientation shifts relative to the surface even if you try to keep it “fixed.” Drag something from equator to pole on a real globe and it turns—this is holonomy.

Demonstration of automatic rotation during poleward movement

Why Countries Rotate

Most tools fake movement in flat 2D space, causing accumulated distortion. TrueSize instead:

1. Moves shapes along great‑circle paths (geodesics)
2. Applies spherical parallel transport for orientation
3. Preserves true area via 3D-first math
4. Corrects minor projection drift iteratively

Holonomy Toggle

Settings panel > Holonomy checkbox:

✅ Enabled (Realistic)

• Natural rotation with latitude change
• Best for teaching spherical geometry / accuracy

⬜ Disabled (North‑Locked)

• Keeps “north up” for readability

Why It Matters

Holonomy handling avoids accumulated angular error and misleading orientation. The engine ensures:

• High positional fidelity (≈0.0001° tolerance)
• True area invariance
• No artificial shear/stretch artifacts

Bottom line: Holonomy support is a core differentiator—delivering the most authentic country comparison experience.

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Next: Customize visuals in appearance settings.