[Talk-ca] GeoTiff in JOSM

Paul Norman penorman at mac.com
Wed Sep 7 07:35:51 BST 2011

> -----Original Message-----
> Subject: Re: [Talk-ca] GeoTiff in JOSM
> On Fri, Sep 2, 2011 at 12:55 PM, penorman <penorman at mac.com> wrote:
> > I'm at work and going on vacation so I can't give a detailed answer
> > for a few days, but this might help
> No problem, any help is appreciated.
> > Once the tiles are made you can serve the directories with apache or
> > another web server.
> Ah, okay I didn't realize it was that simple.

I believe you can also have JOSM get files directly from your hard drive,
but I'm not sure the syntax  to do so on the Mac.
> > xjjk from the OSM IRC channel has a parallized version of gdal2tiles
> > which can significantly help processing times if you have a multi-core
> CPU.
> Would that be maptiler?

Maptiler is essentially a graphical front-end to gdal2tiles. Xjjk's version 
is the command line version modified. My iMac broke awhile back so I'm not 
sure how easy/hard GDAL is to set up with python bindings on OS X.

> I've got a dual quad-core Xeon Mac Pro with 14 gb of ram so a
> parallelized version would be a must. :)

You'll still be limited by your CPU :P

> I'll have to give it a shot and see how long it takes to process some
> portion of my GeoTiff.  The tiled GeoTiff is about 16 GB, where the
> original MrSid is 1.9GB.  Might be doable. :)

What I did for testing was work on a small section downloaded separately and
benchmarked with different image scaling methods. The three worth
considering are nearest, antialias, and lanczos. Nearest is fastest,
preserves sharp edges but has the worst quality. Antialias is decently fast,
decent quality. Lanczos is the best quality, preserves edges but is
extremely slow.

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