VectorPaint compass roses: check directions, symmetry and label orientation

English translation of the Chinese original, translated on 2026-11-03. Original publication dates, attribution, code and version notes are retained.

A compass rose can decorate a map and practise shared centres and direction labels. Draw eight directions manually, verifying cardinal points before diagonals. The result has a fixed orientation: it does not read device sensors or substitute for an actual map, positioning or navigation.

Define what the top of the diagram means

Use an 800 by 800 pixel canvas and explicitly define north at top, south below, west left and east right for this exercise. An actual map needs its own orientation check; screen top is not automatically true north. Reserve outer label space and establish one centre using horizontal/vertical references and a temporary dot. Keep labels separate from geometry so changing the outer radius does not move the centre. Verify the written convention before drawing points.

Build the four cardinal points

Draw a narrow closed north-pointing triangle, then construct south, east and west points with equal initial lengths and widths. All must share the same centre relationship. Duplicating and rotating about a piece’s own centre may still require repositioning. Use available transformations without assuming a radial-array tool. Inspect the monochrome cross for vertical and horizontal symmetry before adding split-colour faces.

Place diagonal points between cardinal ones

Add shorter northeast, southeast, southwest and northwest points between the cardinal ones. Check each against the common centre and keep lengths comparable so one diagonal does not resemble another primary direction. Remove ordinary diagonal reference lines afterward. Inspect joins for protruding overlapping corners and check the four-long/four-short structure at small size. Keep simple complete faces if extra subdivisions become noisy.

Audit direction labels by meaning

Place the four cardinal labels first, then diagonals clockwise, reading each and identifying its point. Audit copied words carefully and prepare a full-word key before using English abbreviations. Keep labels upright rather than inverting the lower ones merely to follow a circle. Maintain comparable visible gaps from points, allowing longer labels more room without invading neighbouring directions. Check semantic correctness separately from visual neatness.

Use two values without implying extra data

Split points into lighter/darker faces if useful, applying one consistent rule. Do not imply wind speed, magnetic declination or other unprovided measurements. Colour supports shape recognition; points and words carry direction. Inspect the centre without labels and check value separation in monochrome. If a cardinal point is highlighted, state that it is decorative rather than a sensor-driven magnetic-north indicator. Visual treatment does not create direction-finding capability.

Recheck label conventions after rotating the diagram

Rotate the complete graphic in a copy and observe the error if labels are left behind. Decide whether a real use rotates with its map or stays fixed, then maintain the chosen convention. Do not rotate points while leaving north unchanged. This tests a visual dependency, not numerical magnetic bearings. Restore the north-up exercise and compare with its draft. Label a rotated decorative use as decoration rather than presenting it as a reliable direction marker.

Check the centre and smallest labels in output

Save the editable source and inspect all tips, the centre and longest labels in the export. A separate four-cardinal simplification may suit small sizes; label it and preserve the eight-direction original. Test light faces and narrow tips on intended backgrounds. For map use, verify map orientation independently. Name direction count, size and revision and read the final file clockwise to exclude leftover test rotations.

Check the convention before repairing reversed directions

For reversed east/west, rule out a mirrored test or changed viewpoint and confirm the north-up convention. Reposition an individually rotated point to the shared centre rather than moving every label around wrong geometry. Simplify heavy central overlap instead of hiding it through global transparency. Inspect fonts and object scaling for distorted text. Recheck cardinal points, diagonals, labels and any destination map separately whenever the graphic carries directional meaning.