Hi Robert,

Thanks for clarification. I have thought --geocentric options generally
using for spherical terrain like whole earth terrain database (i.e
bluemarble world) and --terrain option for flat terrain. And have used both
option seperately to create terrain but haven't tried both of them. So I
misunderstood usage.

Regards.

2008/12/12 christophe loustaunau <christophe.loustau...@gmail.com>

> Hi,
>
> I have test your data and there is strange things.
> If I use this command line :
> osgdem --terrain --geocentric -t hillsmall -o hillsmall.ive
> osgdem reproject the two Geotiff and create two temporary files. But it
> seems not to use it, as in the output database
>  the tiles no not line up.
>
> But if you put these two temporary files into the directory /hillsmall and
> run again osgdem with the same command line
> osgdem --terrain --geocentric -t hillsmall -o hillsmall.ive
> The output database is ok, everything lines up ! (see the sceenshot).
>
> I think osgdem do not use the temporary files, but I don't know why. Maybe
> you could debug it.
> Anyway, you could reproject you files and then everything will work fine !
>
> Hope this help.
>
> Regards.
>
>
> On Fri, Dec 12, 2008 at 7:46 PM, Tueller, Shayne R Civ USAF AFMC 519
> SMXS/MXDEC <shayne.tuel...@hill.af.mil> wrote:
>
>> All,
>>
>> I finally have two small Geotiff tiles (1m resolution) that I've
>> experimented with to examine this problem. I run them through VPB and they
>> first get reprojected (via GDAL I presume) into temporary files. I then
>> load
>> the two temporary reprojected files into OpenEV for examination and they
>> still appear to line up as they did before being reprojected. That would
>> seem to suggest that the problem isn't with the reprojection step (or what
>> GDAL is doing).
>>
>> Once VPB installs them into the database, they do NOT line up as I have
>> shown in my previous email with the screen capture. This would suggest
>> that
>> VPB is doing something that is shifting them off so they don't align.
>>
>> I've attached the two GeoTiff tiles if anyone wants to reproduce this
>> problem.
>>
>> Using VPB, I'm issuing the command:
>>
>> osgdem --TERRAIN --PagedLOD --geocentric -t hillsmall -l 8 -o
>> hillsmall.ive
>>
>> The "hillsmall" directory contains the two tiles. Interestingly, when I
>> remove the "--geocentric" flag from the above command, things look fine
>> for
>> a flat database and the tiles align (which isn't surprising). It's almost
>> as
>> if the spheroid between the tiles and what VPB is using are not matched.
>>
>> Any ideas on what's going on?
>>
>> -Shayne
>>
>> -----Original Message-----
>> From: osg-users-boun...@lists.openscenegraph.org
>> [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of J.P.
>> Delport
>> Sent: Wednesday, December 10, 2008 11:39 PM
>> To: OpenSceneGraph Users
>> Subject: Re: [osg-users] discontinuity in texture in VPB...
>>
>> Hi,
>>
>> I'd also suggest what Christophe said. Do the projection of some tiles
>> manually before VPB is run. I normally use something like:
>>
>> gdalwarp -t_srs "+proj=latlong +datum=WGS84" -r bilinear $name
>> ../reprojected/$newname
>>
>> Then load the tiles into something like QGIS (http://www.qgis.org/) to
>> see if they line up.
>>
>> jp
>>
>> christophe loustaunau wrote:
>> > Hi Shayne,
>> >
>> > Maybe you could reproject your imagery to a geographic projection with
>> > gdal (gdal_translate) and see if you have the same artifact.
>> > You will know if it's a VPB or a gdal reprojection problem.
>> >
>> > On Wed, Dec 10, 2008 at 6:14 PM, Tueller, Shayne R Civ USAF AFMC 519
>> > SMXS/MXDEC <shayne.tuel...@hill.af.mil
>> > <mailto:shayne.tuel...@hill.af.mil>> wrote:
>> >
>> >     I've built a geocentric database using VBP 0.9.7. <http://0.9.7.>
>> >     The imagery is GeoTiff tiles that are NAIP 1 meter UTM and the
>> >     elevation is DTED level 1. The GeoTiffs appear to be reprojected by
>> >     VPB (I assume using GDAL internally) for the geocentric database
>> >     setting. Things appear to build just fine without error but when I
>> >     view the database in OSG, I see a nasty discontinuity across texture
>> >     tile boundaries. You can clearly see this in the airfield picture
>> >     that is attached. The landing strip does not line up across the tile
>> >     boundary. I've verified that the tiles themselves are correct across
>> >     boundaries before I fed them into VPB. The discontinuity appears
>> >     regardless of the LOD that is being paged in.
>> >
>> >
>> >
>> >     My question is, is this an artifact that I must live with since the
>> >     original imagery is based in UTM and the reprojection that VPB does
>> >     (or GDAL) introduces inaccuracies when going to a geocentric
>> >     database? Is there something else I can do to eliminate these
>> >     discontinuities?
>> >
>> >
>> >
>> >     Any input or ideas anyone can suggest to eliminate these
>> >     discontinuities in the database would be welcome.
>> >
>> >
>> >
>> >     Thanks,
>> >
>> >     -Shayne
>> >
>> >
>> >     _______________________________________________
>> >     osg-users mailing list
>> >     osg-users@lists.openscenegraph.org
>> >     <mailto:osg-users@lists.openscenegraph.org>
>> >
>> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>> >
>> >
>> >
>> >
>> > --
>> > Christophe Loustaunau.
>> >
>> >
>> > ------------------------------------------------------------------------
>> >
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>> >
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>
>
> --
> Christophe Loustaunau.
>
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-- 
Ümit Uzun
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