Hi Frank, You're absolutely right. Changing those values in mapresample.c to 10 removed the artifacts when using a WMS request. They're still present when the request is made via mapscript though. I need to manually code a mapscript example though, because right now I'm testing that via TileCache, and I'm not 100% certain how the image is being requested. Can you think of a reason why WMS would be different from a straight read and reproject through mapscript?
cc'ing TileCache list and mapserver lists as well -- On Tue, Nov 18, 2008 at 5:58 PM, Frank Warmerdam <[EMAIL PROTECTED]>wrote: > Roger André wrote: > >> Hi Frank, >> >> I've theorized all sorts of reasons for what I'm seeing. So far none of >> them are right. Basically, if I take a really high-res epsg:4326 image, and >> serve it up through Mapserver in epsg:900913, there are instances where I >> get images back which are missing rows of pixels at the bottom of the image. >> If I reduce the resolution of the image the lines go away. I haven't yet >> figured out at what resolution the problem starts to appear. >> >> I just tested the idea of changing the values in the warper code: >> First: >> nResWinSize += 100; >> Then: >> nResWinSize += 500; >> >> Then rebuilt gdal. Didn't seem to make a difference. >> > > Roger, > > Are you sure the GDAL warper is being used? If the reprojection is being > done by MapServer it will be using the MapServer warper. > > Try changing the +- 1.0 values to larger values in the following code in > mapserver's mapresample.c: > > /* -------------------------------------------------------------------- */ > /* Project desired extents out by 2 pixels, and then strip to */ > /* available data. */ > /* -------------------------------------------------------------------- */ > memcpy( &sOrigSrcExtent, &sSrcExtent, sizeof(sSrcExtent) ); > > sSrcExtent.minx = floor(sSrcExtent.minx-1.0); > sSrcExtent.maxx = ceil (sSrcExtent.maxx+1.0); > sSrcExtent.miny = floor(sSrcExtent.miny-1.0); > sSrcExtent.maxy = ceil (sSrcExtent.maxy+1.0); > > > See if that helps. Currently there is no processing option that does > what SOURCE_EXTRA does, though it might be worth adding one. > > > Best regards, > -- > > ---------------------------------------+-------------------------------------- > I set the clouds in motion - turn up | Frank Warmerdam, > [EMAIL PROTECTED] > light and sound - activate the windows | > http://pobox.com/~warmerdam<http://pobox.com/%7Ewarmerdam> > and watch the world go round - Rush | Geospatial Programmer for Rent > >
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