[osg-users] [VPB] Overriding source reprojection requirement invpbmaster

[Norman Vine]

Glenn Waldron writes:
> 
> Robert,
> 
> Exactly: it is quite possible for different WKT strings to 
> represent the same CS -- I don't think there is a canonical 
> WKT representation per se. I have the same challenge in osgGIS.
> 
> ECW=>GeoTIFF would work but ... unfortunately most of my 
> ECW's are just plain large -- in one case I have 0.15m 
> imagery covering 4000 sq kms.

Glenn,

Have you tried using GDAL's VRT format to pass the projection info
http://www.gdal.org/gdal_vrttut.html

In a nutshell create a .vrt file with the correct projection

 gdal_translate -of vrt -a_srs $YOUR_SRS $IN_FILE.ecw $OUT_FILE.vrt

You may need to tweak the resultant .vrt file

Then pass VPB the .vrt files instead of the ecw files

Of course this assumes you know your desired SRS
http://spatialreference.org/ is a handy site

HTH

Norman

> 
> If you do have the time, I have uploaded a sample dataset 
> that demonstrates the issue. There is a small ECW and a 
> corresponding DEM (GeoTIFF). They are both WGS84. The build 
> command line is included:
> 
>   http://pelicanmapping.com/downloads/ecw-sample.zip
> 
> FWTools contains a pre-built GDAL library with ECW support included:
> 
>   http://fwtools.maptools.org/
> 
> Thanks again for your continued great work! I am especially 
> appreciative of the upgrades to DatabasePager and look 
> forward to test-driving this soon.
> 
> Glenn
> 
> 
> On Sat, Mar 29, 2008 at 8:36 AM, Robert Osfield 
> <robert.osfield at gmail.com> wrote:
> 
> 
> 	Hi Glenn,
> 	
> 	If VPB is reading the coordinate systems for the source and the
> 	required target coordinate system and not matching them it'll
> 	reproject, this matching does rely upon the WTK strings 
> to be equal,
> 	so perhaps this is where the divergance is occurring.
> 	
> 	I don't have any ECW data or plugin available under 
> Linux so I can
> 	test this route personally.  Try using gdal to convert 
> from ECW to
> 	GeoTiff and pass the GeoTiff's into VPB.
> 	
> 	Robert.
> 	
> 
> 	On Sat, Mar 29, 2008 at 12:28 PM, Glenn Waldron 
> <gwaldron at gmail.com> wrote:
> 	> Robert,
> 	>
> 	> I didn't explain myself properly. All my data is 
> indeed reprojected in
> 	> advance. The issue is that vpbmaster just *thinks* 
> the data needs
> 	> reprojection -- I suspect the fault lies with the ECW 
> plugin -- and so I'd
> 	> like to override the check and tell vpbmaster to 
> forge ahead anyway and
> 	> treat the data as if it needs no reprojection. Which 
> it doesn't. :) Does
> 	> that make sense?
> 	>
> 	> I hope you enjoyed your walk! Glenn
> 	>
> 	>
> 	>
> 	> On Sat, Mar 29, 2008 at 5:20 AM, Robert Osfield 
> <robert.osfield at gmail.com>
> 	> wrote:
> 	> > Hi Glenn,
> 	> >
> 	> > It's correct vpbmaster refuses to do a build if the 
> sources aren't all
> 	> > the same coordinate system as otherwise running 
> osgdem on multiple
> 	> > processes at the same time would cause multiple 
> reprojections on the
> 	> > same data at the same time and an unholy mess.
> 	> >
> 	> > The way to manage the reprojection is do it as a 
> preprocessing step,
> 	> > creating a cache of reprojected data.  For this you 
> use another tool
> 	> > vpbcache.   I'm looking after my little 4 year old 
> right now so can't
> 	> > answer any further right now - we're going out for walk!!
> 	> >
> 	> > Robert.
> 	> >
> 	> >
> 	> >
> 	> >
> 	> > On Sat, Mar 29, 2008 at 12:50 AM, Glenn Waldron 
> <gwaldron at gmail.com>
> 	> wrote:
> 	> > > Robert,
> 	> > >
> 	> > >  I've noticed that vpbmaster refuses to continue 
> if it detects that all
> 	> > > sources are not in the same coordinate system. I 
> can certainly
> 	> understand
> 	> > > why. That said, is there a way to override this 
> decision and tell
> 	> vpbmaster
> 	> > > to "trust me" that all sources are in a common projection?
> 	> > >
> 	> > >  Case in point: GDAL's ECW (ER Mapper compressed 
> wavelet raster) plugin
> 	> is
> 	> > > sometimes not able to correctly parse the 
> coordinate system information
> 	> in
> 	> > > the file. (This is a known issue -- 
> http://www.gdal.org/frmt_ecw.html).
> 	> So
> 	> > > vpbmaster won't run since it thinks the ECW is in 
> a different projection
> 	> > > than other input layers.
> 	> > >
> 	> > > I tried using the "--cs" option to manually 
> specify the CS; also
> 	> > > "--ReprojectSources False"; no luck in either 
> case. I'm running on Win32
> 	> > > with the latest SVN head of OSG and VPB.
> 	> > >
> 	> > >  Glenn
> 	> > >
> 	> > > --
> 	> > > Glenn Waldron : Pelican Mapping : 
> http://pelicanmapping.com :
> 	> 703-652-4791
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> 	> --
> 	>
> 	> Glenn Waldron : Pelican Mapping : 
> http://pelicanmapping.com : 703-652-4791
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> 
> -- 
> Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : 
> 703-652-4791 
>