On 23 Jan 2008, at 12:23, Torsten Rahn wrote: > Hi Artem, > > On Wednesday 23 January 2008 11:06:41 Artem Pavlenko wrote: >> Hi Torsten, >> Glad you like the screenshot. I'll post another one soon :) >> Yes, you're right mercator would be wasteful. When I got spare >> moment I'll try different tile sizes to see if this affects final map >> quality. > > No, the tilesize shouldn't affect the render quality at all. Ok. > > Manually adjusting the point at which Marble switches to a > different tile > level could have a positive effect. > > Right now it happens in > > void AbstractScanlineTextureMapper::selectTileLevel( ViewParams* > viewParams ) > > using the formula > > double linearLevel = ( 2.0 * (double)( radius ) > / (double) ( m_tileLoader->tileWidth() ) ); > > I guess ideally the size of the tile on the screen would match > about the size > of the original tile. You can check this by changing line 119 in > marble/src/lib/TextureTile.cpp from > > bool tileIdVisible = false; if(tileIdVisible) > m_painter.paintTileId(theme); > > to > > bool tileIdVisible = true; if(tileIdVisible) m_painter.paintTileId > (theme); > > > This will enable you to see the tile borders and the filenames + > tile level > visually directly on the screen. This "Debug Mode" is very helpful > when you > work with tiles in Marble!
Thanks, I'll try this. > >> Maybe you can afford better resampling at high zooms for smoother >> results? > > I'm not sure whether this can be implemented easily at sufficient > speed. Right > now Marble just looks up the "exact" color value on the map for > each point on > the screen > We could try to do some more sophisticated high quality rendering > when the > user stops moving the map. I think this could work. if you're planning to pull tiles from a web service, then rendering fast (scaled) globe and repainting on each tile arrival (with bilinear interpolation for example) shouldn't be a problem. I did something like that - pulling tiles from VE and warping them on-fly into NatGrid and it worked really well (qt4). > Whether it's possible to do the same at acceptable > speed while moving is a completely different question though .... I think for 'moving' current approach works well. > >> BTW, I rendered tiles (for marble) in Lat/Lon aka Geographic, Plate >> Carre, equirectangular,cylindrical equidistant, unprojected etc. >> Still, there are too many re-sampling artifacts. I'll try smaller >> tile sizes .. > > Could you send me a screenshot of Plate Carre, so I get the idea > how it looks > like? > Here you go : http://artem.dev.openstreetmap.org/files/marble-osm- flat.jpg I found 'magic' zoom level when there's minimal distortion. Cheers Artem > > Best Regards, > Torsten > > PS: Is the OSM-Talk Moderator on holidays? > >>> Best Wishes, >>> >>> Torsten >>> >>>> Best >>>> Artem >>>> >>>>> Best wishes, >>>>> >>>>> Torsten >>>>> >>>>> -- >>>>> Torsten Rahn >>>>> >>>>> Tel.: 0 21 61 - 46 43 - 192 >>>>> >>>>> credativ GmbH, HRB Mönchengladbach 12080 >>>>> Hohenzollernstr. 133, 41061 Mönchengladbach >>>>> Geschäftsführung: Dr. Michael Meskes, Jörg Folz >>> >>> -- >>> Torsten Rahn >>> >>> Tel.: 0 21 61 - 46 43 - 192 >>> >>> credativ GmbH, HRB Mönchengladbach 12080 >>> Hohenzollernstr. 133, 41061 Mönchengladbach >>> Geschäftsführung: Dr. Michael Meskes, Jörg Folz > > > > -- > Torsten Rahn > > Tel.: 0 21 61 - 46 43 - 192 > > credativ GmbH, HRB Mönchengladbach 12080 > Hohenzollernstr. 133, 41061 Mönchengladbach > Geschäftsführung: Dr. Michael Meskes, Jörg Folz _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk