Drawing polygons that actually look clean

A region polygon is the most visible thing on your map and also the easiest to do badly. The default instinct is to click fast — a dozen vertices, close the shape, move on. The result is technically a polygon, but it has the visual signature of a polygon drawn in a hurry: long, awkward sides, weird notches at intersections, and a fill that almost-but-not-quite matches the underlying streets.

This is a practical checklist for reviewing a boundary before you publish it. The goal is to make neighbouring shapes easy to distinguish and keep later edits manageable.

1. Trace, don’t approximate

When a region follows a road, follow the road exactly. A polygon edge that runs visibly inside or outside a road by ten or twenty pixels is the single biggest tell that a map was rushed. The eye picks it up immediately, even if the viewer can’t articulate why the map feels off.

2. Vertex placement: corners and curves only

Every vertex you add is a small commitment to a future maintainer. Add them where the boundary changes direction (corners) or where a curve needs at least three points to look smooth. Adding extra vertices on a straight stretch makes the line wobble when somebody adjusts a single point later.

3. Use diagonals for natural boundaries

Rivers, coastlines, and tree lines aren’t built on a grid. If a region edge follows one, accept the diagonals. Forcing every vertex onto a 90-degree turn produces a stairstep effect that looks like a Minecraft screenshot.

4. Close to the snap

Use your editor’s finish or close action, then zoom in on the first and last points. If the boundary is intended to meet a road or another region, check that edge at both the map’s normal viewing scale and a closer zoom.

5. Avoid sub-pixel slivers between regions

When two regions share a boundary, draw the second one by retracing the first one’s vertices, not by drawing a fresh boundary that “looks the same”. Two polygons that are visually adjacent but not vertex-shared will produce thin, transparent slivers when the map is zoomed out, and tiny overlap artefacts when it’s zoomed in.

6. Mind the legibility of small regions

A region that’s smaller than the label inside it has a labelling problem, not a sizing problem. Three options, in order of preference: shorter label, label outside the region with a leader line, or merge the small region into a neighbour and represent the original as a marker instead.

7. Don’t cross your own edges

Most editors will let you save a self-intersecting polygon, and most renderers will draw it incorrectly — the fill flips inside-out across the crossover. If you ever see a region with a missing chunk you didn’t draw, this is almost certainly the cause. Delete the offending vertex and retrace.

8. Concave is fine, donut holes are usually a smell

Concave (L-shaped, U-shaped) regions are normal. A region with a hole cut out of it for an unrelated enclave is more often a sign that the enclave should be its own region with its own category, drawn on top.

9. Respect the line weight at zoom-out

Thin borders (1px) look elegant when you’re drawing them. They become invisible at typical phone zoom levels. Test every region at the zoom level your viewers actually use. If the border disappears, bump the weight or rely on fill alone.

10. Pick fill opacity once and stick with it

Mixing 30% and 60% fill across regions is one of the quickest ways to make a map look amateur. Pick one opacity for the whole map (we like 35-40%) and only deviate when a region is intentionally different — say, a striped “contested” overlay sitting on top of a solid one.

11. Avoid pure red and pure blue against satellite imagery

Saturation does not survive a satellite-style basemap. Pure red gets washed out by warm tones; pure blue blends with water. Lean toward slightly desaturated, slightly bright colours — they’ll read on every basemap, including dark, light, and terrain.

12. Save a screenshot of every map you like

The fastest way to get better at drawing polygons is to keep a small collection of region styles you’ve seen elsewhere and steal liberally. Border weight, label placement, opacity, palette, marker icons — all worth ripping off shamelessly. Steal good, and steal often.

One last habit: leave the map for an hour, then look

The single highest-leverage habit isn’t a drawing technique. It’s walking away. Come back in an hour and look at the map cold, on your phone if possible, and ask “what would I fix?”. You will instantly see two or three problems you couldn’t see while you were drawing. Fix those, ship, and stop touching it. Maps benefit enormously from a final pass with fresh eyes; they almost never benefit from a sixth.