[Xastir] GeoPDF

[Tom Russo]

On Mon, Sep 05, 2011 at 05:43:50PM -0400, we recorded a bogon-computron collision of the <shadow at gmail.com> flavor, containing:
> On Mon, Sep 5, 2011 at 1:42 PM, Tom Russo <russo at bogodyn.org> wrote:
> > On Mon, Sep 05, 2011 at 09:08:10AM -0600, we recorded a bogon-computron collision of the <russo at bogodyn.org> flavor, containing:
> >>
> >> I'm not going to hack Xastir to handle 24-bit, but I've been working on a
> >> script to deal with this process (and an extension of it) and hope to release
> >> it this afternoon.
> >
> > Or this morning. ?Please do a cvs update and look for the "geopdf2gtiff.pl"
> > script in the scripts directory. ?It installs to /usr/local/lib/xastir, too.
> >
> > geopdf2gtiff.pl foobar.pdf
> >
> > will collar strip, warp, format change to Geotiff and dither to 8-bit color.
> > The output will be foobar.tif.
> >
> > Unfortunately, I've found that some geopdfs contain INCORRECT specifications
> > of their own neatlines --- these GeoPDFs say that the neatline is the same
> > as the entire image, rather than the boundary of the map data itself. ?There's
> > nothing to be done about that other than to hand-craft an FGD file with the
> > lat/lon of the north, south, east, and west neatlines. ?But many GeoPDFs
> > have correct specifiers, and the output of geopdf2gtiff.pl will be precisely
> > a geotiff that can be used in Xastir with a minimum of fuss.
> 
> there's a script which will make up an fgd for a grid-named (e.g.
> o40080a1) geotiff
> and certainly if you have any georeferencing you can guess that, so it
> shouldn't be that
> hard.

No, it isn't difficult.  Hence my most recent script update.  It guesses the 
boundaries as best it can if you tell it to ignore the stored neatline.  The
mapfgd.pl script isn't much help, because it computes the neatlines from the
file name directly.  But it wasn't hard to come up with a scheme that worked.

Using "zip" to compress the geotiff file isn't what I meant --- there's image
compression available in the tiff library, and usually one creates tiff files
that have internal PACKBITS compression.  Most software can still read it 
that way, but for some reason Xastir is choking on the files if I produce
them with PACKBITS compression.  I haven't figured out why, since USGS
geotiff maps are compressed that way.

-- 
Tom Russo    KM5VY   SAR502   DM64ux          http://www.swcp.com/~russo/
Tijeras, NM  QRPL#1592 K2#398  SOC#236        http://kevan.org/brain.cgi?DDTNM
 "One man alone can be pretty dumb sometimes, but for real bona fide
 stupidity, there ain't nothin' can beat teamwork." - Edward Abbey