Raster to vector: turning a map picture into vector (and why tracing fails)

You have a picture of a map — a screenshot, a JPEG from a report, a chunk of PNG — and you need it as vector: to scale it without pixels, recolour it or load it into CAD. The first impulse is to run it through Image Trace in Illustrator or through Vector Magic. The honest answer: for a map that is almost always a dead end. Below is why, and what to do instead.

If you are not sure what vector even means and how it differs from a picture, start with the primer vector maps in plain words.

What tracing actually does

Tracing (Image Trace, auto-vectorisation) looks for areas of a single colour in the raster and outlines them with paths. It works well where the picture is simple and contrasty: a logo, a silhouette, a black-and-white line drawing. A map is the exact opposite — hundreds of thin multicoloured lines, semi-transparent fills and small text.

What you get out:

• Text stops being text. Street names become a bunch of curves. Translating them, changing the font or fixing a typo is no longer possible.
• Lines merge. A road in the raster is a fill with a casing; the tracer sees one shape and outlines its outer edge. Two parallel streets at low resolution fuse into a single blob.
• Layers and attributes vanish. Instead of "buildings", "roads", "water" you get a pile of nameless paths on one layer. You can't toggle a category on or off.
• No coordinates. A vectorised picture is a drawing, not a map: no georeferencing, no scale, no way to measure a distance.
• Thousands of extra nodes. Every pixel jag becomes a path point. The file is heavy and the lines wobble.

There's a legal side too: a screenshot of someone else's mapping service remains their data, and outlining the contours doesn't make it yours. OpenStreetMap data, by contrast, is open under the ODbL licence — usable with attribution.

If you really do need to trace

Sometimes the source genuinely is raster only — an old paper map, a scanned floor plan, a diagram from a book. Then the order is:

1. Raise the source resolution: scan at 600 DPI or above rather than re-saving a JPEG from a messenger.
2. Clean the raster: remove noise, raise contrast, convert to black and white with a threshold if needed.
3. Adobe Illustrator: select the image → Object → Image Trace → Make, then the Image Trace panel, modes Black and White or Limited Color, tune Threshold, Paths, Corners, Noise. Then Object → Expand.
4. Inkscape (free): Path → Trace Bitmap (Shift+Alt+B), mode Brightness cutoff or Edge detection, then Path → Simplify (Ctrl+L) to cut down the node count.
5. Sort the result into layers by hand and re-add the labels as real text, not curves.
6. If you need an actual map rather than a drawing — georeference the raster in QGIS (Raster → Georeferencer) and redraw the objects over it. That takes longer, but the output is real geometry.

Vector Magic and similar online services do the same thing with better default settings — that doesn't remove the fundamental limits.

The right route for a city map

If what you need is a map of a territory rather than one specific old sheet of paper, vectorising a picture is pointless: the vector data already exists. OpenStreetMap stores buildings, roads, water and greenery as geometry with attributes — you just export them in the format you need.

• SVG — for design and print: layers open in Illustrator, Inkscape, Figma, Affinity, and every object is editable separately. What designers do with them is in SVG maps for design, and the format itself in the SVG deep dive.
• PDF — for printing and handing to a print shop: vector, embedded fonts, opens everywhere.
• DXF — for AutoCAD, BricsCAD, nanoCAD and other CAD: layers, real dimensions, measurable distances.

The difference is simple: tracing gives you a similar picture, export gives you real objects. A full comparison of the two worlds is in vector vs raster maps.

Easier — get a ready file straight away

Select the area you need and download it straight as vector: SVG for design, PDF for print, DXF for CAD. You get a clean map of the territory with OpenStreetMap layers — no fused streets, no curves instead of labels, no junk nodes. It's free and takes seconds.

In short

• Tracing a map destroys text, layers and coordinates, and welds neighbouring lines together.
• It's only justified for old paper and scans that don't exist digitally.
• For tracing: scan at 600 DPI or more, Illustrator Image Trace or Inkscape Trace Bitmap + Simplify.
• If you need a real map, take vector directly: SVG, PDF, DXF.
• A screenshot of someone else's service doesn't become yours once outlined; OSM data is open under ODbL.