[Marble-devel] custom marble map trouble

[Torsten Rahn]

Hi again,

for scaling and cropping you absolutely want to install  the "nip2" tool. :-)
It also installs the vips-library. These tools are amazingly fast (read: what 
took me _hours_ using image/graphicsmagick takes _seconds_ using vips).
And they make dealing with huge images an acceptable task.

The interface is a bit non-intuitive imho (and the "Create tiles" menu item 
seemed to be broken in the Ubuntu Hardy packages that I installed).

However I recommend that you look into the "vips" command afterwards: E.g. 

vips im_affine clem_uvvis_bmap_N15_225_warp.tif moon_N15_225.tif 0.791992 0 0 
0.791992 0 0 0 0 7200 7200

scales a 9091x9091 image by a factor of 0.79 down to 7200x7200 using bilinear 
interpolation (unfortunately bicubic interpolation doesn't exist there). 
Likewise there's also a command to crop. Use im_affine instead of im_shrink if 
you want to have at least bilinear antialiasing ( im_shrink doesn't do 
antialiasing / resampling ). More information in the man pages.

The documentation is not nearly as nice as the one for the magick tools but 
it's really a huge time saver when dealing with big images!

If you want to stick to imagemagick/graphicsmagick I recommend that you look 
at the "-limit" option as this will keep the load of the computer low (and 
prevents endless swapping).

Best Regards,
Torsten


On Sunday 19 October 2008 19:24:08 Danuvius wrote:
> Also, somebody wouldn't have a ready-to-use python/bash script using
> imagemagick to create the map tiles out of arbitrarily large original
> map sizes?
>
> Sincerely,
>
> Danuvius
>
> On Sun, Oct 19, 2008 at 1:20 PM, Danuvius <danuvius at gmail.com> wrote:
> > Greetings,
> >
> > Thank you to everybody that helped when last time around I was asking
> > for information about drawing buffers, and creating maps for Marble.
> >
> > I basically managed mostly everything I needed by now... however upon
> > my first attempt at importing a 10800 x 5400 pixel map, the results
> > appear corrupted (though the source map [in terms of the location of
> > physical features] is basically a 1:1 match of existing marble maps).
> >
> > Please see http://spinarette.com/snapshot1.png for a screenshot.
> >
> > Is the visual output indicative of some obvious mistake I made
> > somewhere along the way?
> >
> > Thank you in advance!
> >
> > Sincerely,
> >
> > Danuvius
>
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