[Gdal-dev] Question about building Pyramids

[Christian Mueller]

I need to build pyramdis from a tiled Image having many tiles. Assuming the 
tile size 17*13 and the  scale factor is 2, i have some questions about the 
interpolation methods:

The base for the interpolation has pixel size 34*26 composed of 4 Tiles 
resulting in one Tile of size 17 x 13

nearest neighbour: should work

bilinear: should work, a scale factor of 2 always results in even pixel sizes

cubic,cubicspline: Here is my problem, in my opinion, the pixel size modulo 4 
should be 0. Is it right to expand the base rect with 1 pixel to start the 
interpolation from a 36 x 28 image , the result would be a tile 18*14,  and 
how do i get  the  17*13 image ?

thanks for your hints

christian