Obtaining print quality PDF or PNG output from QGIS?

Question

I work with people who use ArcGIS Desktop and they have found the best resolution output images are made by creating PDFs. They tell me that *.png and the rest out of ArcGIS Desktop are not satisfactory and that they do not bother with them. Typically we are making the output appear in a report and so the PDFs of the maps and words are assembled in a PDF editor package to make the final document.

As a result I have been toying around with QGIS on my Windows 7 machine and notice that the best output comes by printing directly out of the map composer.

This output on my Docuprint C2120 printer is as good as any of the ArcGIS Desktop PDFs and is truly impressive. QGIS makes very attractive maps in this configuration.

However, I do not seem to be able to create PDFs or .pngs and then print them which are anywhere near as good. I find the .svg output to Inkscape unrealiable where, for instance, the grid/graticule may come out oversized.

By way of example, the good quality output is where a sub-6 pt font can be read easily off the printed page.

Any thoughts?

I am using QGIS trunk.

Answer 1

here in my office the solution for press quality maps is to export 300x300px tiff images from print composer. We export only the "core" of the map with the grid and the scale bar. Then in OpenOffice (or LibreOffice) we make the layout and them put the image and print. Very nice results even in A0 maps.
Obs: 4gb of RAM helps a lot.
Obs2: Since Openoffice don't store large images inside the document, if you update the tiff image the map also changes and that is a good tool to create map series.

Answer 2

I think there is an ongoing bug with the Windows version of QGIS where it rasterizes the map before creating a PDF, so you'll likely get poor, bloated PDFs. I think it's a Qt issue because I fixed the code a while back and it works on Ubuntu...

One process I have used in the past is to install a PostScript printer driver (doesn't matter which, an HP colour one is what I use), and set it to always print to file. When you print it'll give you a file dialog box that you use to save the .ps file. Then use ps2pdf (part of the Ghostscript tools) to create the PDF. It's a bit of a pain I grant you, but its only one extra step and usually produces good results.

Answer 3

Similar to MerseyViking's Postscript printer suggestion, you can print to PDF natively on OS X. On Windows use CutePDF. On Linux, try cups-pdf.

These solutions may have line weight issues that need tweaking in Inkscape or Illustrator.

If you have a print server, you set this up once and share with the whole office.

Answer 4

You can also open pdf files in Inkscape. I do this all the time from arc, and generally works well. I typically do each layer as a different pdf and then merge them, then do the labeling in inkscape.

Answer 5

Personally, I tend to generate PNG's set to, say, A3 or even A2 in the QGis composer when I need to assemble a PDF document at A4 - I've never had any quality issues personally even when assembling them in MS Word (so long as I make sure Word doesn't attempt to compress the images).