[OSGeo-Discuss] Proposal: OSGeo Cartographic Library
bruno at 1t3xt.com
Sun Apr 13 22:19:28 PDT 2008
Tyler Mitchell (OSGeo) wrote:
> For me the question of PDF is not limited by number of pages, or options
> that PDF offers, but whether or not it is an efficient format for
> sharing cartographic information - for which, so far, I'd say it fails
> miserably. How many times have I went to a municipal mapping site only
> to find their maps are all in PDF - what a pain! It might just be me
> though :)
It depends on how they are made. Do they have a street index
that allows you to jump to the exact location when you click
on a streetname? Are they made out of raster images converted
to PDF or are they drawn using vector data?
> Also, in the operational/industrial GIS map production environments I've
> been in, we've needed easy ways to print and re-print maps without
> having to open a viewer (and our printers didn't support PDF natively -
> though I assume some do now). To print, I've focused on native plotter
> file formats and/or Postscript since most plotters can support it. Of
> course this isn't going to be good for web distribution.
There are ways to work around that print problem ;-)
> For delivering digital files, I've often converted the PS files into PDF
> but it's been far from ideal.
But then you get a 'flat' PDF without any interactivity.
I don't see any added value when you convert PS to PDF.
> I increasingly believe that web-based
> tools are going to be the only option. So what about off-line
> delivery? A CD or USB runable system is an interesting and more
> effective way than a PDF in some cases, though of course both have some
> memory overhead issues.
> So, is it just me or does stuffing a 1:20,000 topo map into a PDF makes
> a huge file that is virtually unusable unless you have gigabytes of RAM
> and dual processors. Delivering a 40MB PDF to client who is running an
> old computer doesn't bode well for your service ;-)
Er... stuffing a 1:20,000 topo map. The fact that you mention 1:20,000
indicates that you are probably talking about raster images, not about
vector data. If you write the vector data to a PDF, all the data is
compressed. You get really small file sizes when compared to other
In short: the major problem with PDF in the GIS world is a lack of
understanding of the Portable Document Format by people who are
specialized in GIS. Of course PDF sucks if you just stuff if with
raster images or use a PDF that was converted from PS. Even a FOP
generated PDF has no added value.
As soon as I have the time, I'll make you some examples.
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