How do I set an exact map scale in a QGIS print layout?

Select the map item, open Item Properties, and type the denominator in the Scale field (e.g. 25000 for 1:25,000), then lock the layers and the scale so panning the main canvas cannot change it. The scale is only meaningful in a projected CRS with linear units.

What DPI should I export a technical map at?

Set the layout export DPI to 300 for printed deliverables and 150 for screen/PDF review copies. Raster layers limit effective resolution, so a 300 DPI export of a coarse raster will not add real detail, but it ensures text and vector linework stay crisp.

How do I add a correct scale bar and coordinate grid?

Add a Scale Bar item linked to the map; in a projected CRS it reads true ground units. Add a grid in Map Item Properties, choosing the CRS and interval, and enable annotations to label coordinates. Avoid scale bars on geographic (degree) CRS maps.

Should I export a technical map as PDF or SVG?

Export PDF for final deliverables — it preserves vectors, embeds fonts, and can keep map layers. Use SVG only when the map will be edited in a vector editor afterwards, accepting that some QGIS symbol effects rasterize or shift in SVG.

QGIS Print Layout for Technical Maps: Scale & Export

Short answer

A technical map differs from a pretty map in one respect: every measurable element must be true. That means a locked, exact scale in a projected CRS, a scale bar and coordinate grid that read real ground units, a correct north arrow, and an export at the right DPI (300 for print) that keeps vectors as vectors. The Print Layout (formerly Print Composer) is where this is enforced — the map canvas is for exploring, the layout is for committing.

Lock the scale before anything else

Open Project ▸ New Print Layout, add a Map item, then select it and open Item Properties. The single most important field is Scale: type the denominator directly — 25000 gives a true 1:25,000. Do not eyeball it by zooming.

Two settings make the scale trustworthy:

Lock layers and Lock styles for layers so editing the main canvas does not change what the layout shows.
After positioning, treat the scale as fixed. If you later move the map item's extent by dragging, re-enter the scale to restore it.

Scale only has meaning in a projected CRS with linear units (metres or feet). If the project is in EPSG:4326 (degrees), "1:25,000" is meaningless — a degree is not a fixed ground distance. Set the project to an appropriate projected CRS (a UTM zone, a national grid) before building a technical layout, and the map item will inherit it.

Scale bar, grid and north arrow done correctly

Scale bar. Add a Scale Bar item and link it to the map. In a projected CRS it computes true ground length, so a 5 km segmented bar really is 5 km on the ground. Set the units explicitly (km, m) and a clean segment size. A graphic scale bar is preferable to a printed ratio alone because it stays correct if the page is photocopied or resized.

Coordinate grid. In the map item's Grids section, add a grid and set:

Grid CRS — usually the project CRS, but you can overlay a second grid in another CRS (e.g. a UTM grid plus a lat/long graticule).
Interval in map units (e.g. 1000 m).
Annotations on — choose the frame side, format (decimal degrees vs DMS, or full vs truncated easting/northing), and precision.

A grid is what lets a reader recover real coordinates from the printed sheet — essential for a map someone will navigate to in the field.

North arrow. Add a North Arrow picture item. Crucially, for a projected CRS the grid north and true north diverge away from the central meridian (meridian convergence), and magnetic north differs again. Set the north arrow to follow the map and state in the legend or margin which north it shows. For UTM, declaring "grid north" avoids a navigation error in the field.

DPI and resolution — what 300 DPI actually buys you

Set export DPI in the layout (or at export time). Use 300 DPI for print deliverables and 150 DPI for review PDFs. But understand the limit: DPI controls how finely vector elements (text, lines, symbols) are rendered. It cannot add detail to a raster layer that does not have it. A 30 m DEM hillshade printed at 1:10,000 will look soft no matter the DPI, because each pixel covers 30 m on the ground. Match raster resolution to scale: roughly, your raster pixel size should be ≤ 0.2 mm at print scale (at 1:10,000, 0.2 mm = 2 m on the ground, so a 2 m DEM is appropriate).

The page size matters too: set the layout page to the real sheet (A3, A1, ANSI) in Layout properties so margins, bleed and frames are correct, not scaled approximations.

Worked example: a 1:25,000 geology sheet on A3

Project CRS set to the relevant UTM zone (metres).
New Print Layout, page A3 landscape.
Add Map item, set Scale = 25000, position the extent over the survey area, lock layers and styles.
Add a 5 km segmented scale bar (units km), linked to the map.
Add a 1000 m UTM grid with easting/northing annotations on the frame, precision 0.
Add a north arrow (declare grid north), legend (filtered to visible layers), title, data-source/CRS/date credit text, and a small location inset map.
Export: Layout ▸ Export as PDF, DPI 300, enable Always export as vectors and Create geospatial PDF (GeoPDF) if the client wants coordinate-aware PDF.

Export format: PDF versus SVG

PDF is the default for deliverables. QGIS exports vector linework and text as true vectors, embeds fonts, and can preserve map layers (toggleable in the PDF) and a geospatial reference (GeoPDF), letting a recipient query coordinates. Enable Always export as vectors; without it, layers using blend modes or certain effects force a raster fallback for the whole map.

SVG is only for when the map will be edited in Illustrator/Inkscape afterwards. QGIS SVG export is imperfect: some symbol effects rasterize, text can shift, and clipping behaves differently. Treat SVG as an editing hand-off, not a final format.

Common pitfalls and why they happen

Scale bar shows wrong distances. The project is in a geographic CRS, so the bar measures degrees-as-units. Reproject to a projected CRS.
Map item drifts off the area after edits. The extent moved; re-enter the scale and reposition, then lock. Use Lock layers to stop canvas changes leaking in.
Blurry text or thin lines in the PDF. Export rasterized the whole layout because a layer used a blend mode or Always export as vectors was off, or DPI was set to 96. Fix the offending layer and export vectors at 300 DPI.
Legend lists hidden or irrelevant layers. Auto-update is on with everything checked. Turn off Auto update and curate the legend to the layers actually shown.
North arrow points "up" but the grid is rotated. A rotated map item, or grid-vs-true north confusion. State which north you mean and rotate the arrow to match the map item rotation.
Fonts substituted on the recipient's machine. Only happens for editable projects, not PDFs with embedded fonts — another reason PDF is the safe deliverable.

QA before sign-off

Verify the scale by measuring a known feature on the exported PDF against the scale bar.
Confirm grid coordinates against a known point (a benchmark, a surveyed corner).
Check the credit block carries CRS (with EPSG), data sources, dates and author — a technical map without provenance is not a technical map.
Open the final PDF on another machine to confirm fonts, vectors and any GeoPDF coordinate readout survived.

Bathyl perspective

We treat the layout as the contract: anything a reader can measure off the sheet — scale, grid, bar, north — has to be defensible. So we lock the scale, declare the CRS and the kind of north in the margin, size rasters to the print scale, and export vector PDF at 300 DPI. A technical map earns trust when its measurements hold up to a ruler and a GPS, not just to the eye.

QGIS Print Layout for Technical Maps