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QGIS exceeds my expectations by a country mile. I am impressed. But;

I work with people who use Arc and they have found the best resolution output images are made by creating PDFs. They tell me that .png and the rest out of Arc are not satisfactory and they don't 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 Win7 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 Arc PDFs and is truly impressive. QGIS makes very attractive maps in this configuration. However I don't 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. Obviously quality linework in cartography is the holy grail....

Any thoughts?

....Also I am using QGIS trunk...

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You shouldn't use PNG or any raster file format for output of vector data where quality is a concern. –  Sean May 17 '11 at 16:23
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Not necessarily - it depends on your final output device. If you're going to be printing it on say a 600 dpi printer, then saving it as a raster at 600 dpi will produce an output as good as vector. The difference being whether the software rasterizer is better than the printer driver's one. Obviously file size may be an issue, but if you have a raster base map, then there's not going to be much difference. –  MerseyViking May 18 '11 at 8:11
    
In the interest of anyone following this thread, I see now there is more control in the QGIS Composer than I realised, my mistake! See also this bug trac.osgeo.org/qgis/ticket/2436#comment:8 –  BWill May 20 '11 at 6:38
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I disagree that PDF output out of ArcMap is impressive. Perhaps for simple maps containing vector features and simple labels. For professional maps with 100 layers and multiple transparent raster layers the PDF exporter in ArcGIS will either not work at all or be so plagued with various issues that t becomes un-usable. The only way to overcome this issue (and it might be something worth exploring in QGIS as well) is to export to high resolution tiff. Or Just export the map frame and finish the map in Illustrator / CorelDraw. BTW exporting to AI in ArcMap does not work either. –  Jakub Jul 29 '11 at 12:41
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5 Answers 5

up vote 10 down vote accepted

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. enter image description here

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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.

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Regarding the rasterizing, I find if you go with all "New Symbology" this doesn't happen and everything comes out as vectors. If you have even one layer using the old symbology then it will convert it to a raster layer. –  Nathan W May 17 '11 at 14:22
    
Thanks guys, how do I know if it is doing that, converting to a raster? –  BWill May 17 '11 at 22:39
    
Well I printed out a map with a large v1 symbol and a few v2 symbols and you can very easily tell the difference between the two. –  Nathan W May 18 '11 at 4:30
    
Well yes Nathan.... what I mean is if I were to try and trouble shoot a map with many layers.... probably I will work it out. –  BWill May 20 '11 at 3:49
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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.

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Thanks Sean, I have been printing to NitroPDF and it gives pretty much the same result as the PDF generator in QGIS. –  BWill May 17 '11 at 22:38
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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.

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I have not noticed that QGIS will seperate the layers in the output PDF. I am told that Arc does this and then you can toggle the layers on and off in the PDF viewer, but I have not seen any example in QGIS. Thanks –  BWill May 17 '11 at 22:40
    
@BWill- According to answers to a similar question a while back, preserving layers is not possible with QGIS at this time. gis.stackexchange.com/questions/7078/… –  RyanDalton May 17 '11 at 23:09
    
I just toggle the visibility of each layer and then export as separate pdfs for use with Inkscape. I don't know about preserving layers within a pdf. –  dslamb May 19 '11 at 19:25
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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).

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