Creating PDF with vector data in QGIS

Question

I got my geospatial file ready with all information in vector data (except background PNGpng) in QGIS. Now I wish to save a PDF format for a second party. The vector lines are required to be visible as a thin line at any zoom level, for the PDF will be very spacious and needs to be zoomed in on a large scale.

I export my file into PDF, but the vector lines turn up to be very thick and do not scale comparatively. They seem to appear in a fixed size, but I need them to stay constantly thin when zooming in the pdf (so that they don't cover up important small information in the background). I guess I've got something wrong in my settings, but cannot find my mistake.

Answer 1

To ensure that your vector lines remain thin and visible at any zoom level in the exported PDF from QGIS, you need to adjust the settings appropriately during the export process. Here's how you can do it:

In QGIS, make sure your map canvas is set up the way you want it to appear in the PDF. This includes the correct scale, symbology, and labeling.

Go to "File" in the menu bar and select "Print Composer." This will open the Print Composer window, where you can create and export your map layout.

In the Print Composer, click on "Layout" in the menu bar and then select "Add Map."

Draw a rectangle on the Print Composer canvas to define the extent of your map. This is where your map will be displayed.

In the "Item Properties" panel on the right side, you can adjust the map's properties, such as scale, rotation, and position.

Pay attention to the "Scale" setting in the "Item Properties" panel. Ensure that the scale is set to 1:1 or any other appropriate value that represents the true scale of your data.

Under the "Composition" tab in the "Item Properties" panel, check the box next to "Follow map theme (experimental)." This ensures that your map exports with the same symbology and scale as shown in the QGIS canvas.

Now, you can customize the symbology of your vector lines. In the Layers panel on the left side, right-click on the layer containing the vector lines, and select "Properties."

In the "Layer Properties" window, go to the "Symbology" tab. Choose a simple and thin line style for your vectors. Make sure the line width is set to a small value (e.g., 0.1 or 0.2).

After you have set up your map layout and adjusted symbology, go back to the main QGIS window and select "Project" from the menu bar, then choose "Export as PDF."

In the "Save As PDF" dialog, choose the desired settings. Under the "Layout" section, select the layout you created in the Print Composer.

In the "Quality and Resolution" section, ensure that "Export resolution" is set to a high value, such as 300 dpi, to maintain clarity when zooming in.

Click "Save" to export the PDF with the specified settings.

By following these steps, you should be able to export a PDF with vector lines that remain thin and visible at any zoom level, preserving the details in the background.