Martin Desruisseaux <[EMAIL PROTECTED]> wrote on 03/18/2006 11:06:56 PM:
> Bryce L Nordgren a écrit : > > * New section on Positioning classes. ISO 19123 provides a means to > > specify affine coordinate conversions and general coordinate > > transformations, but not non-affine coordinate conversions. Most Map > > projections fall into this category. Proposed an addition which plugs this > > hole. > > I will try to look at the new section as soon as I can (I have too > many thing to do in the same > time...). I'm not sure what the ISO 19123 coordinate conversions is > for. But OGC 01-004 had a "grid > to CRS" transform, which is really an affine transform in the vast > majority of cases. Reprojection > were handled by the "Resample" operation, which is an other story. No problem. "Positioning" classes perform the transform from the EngineeringCRS of the Grid (generally in Integer indicies) to some external CRS. If the grid is already sampled in terms of the external CRS (e.g. UTM), then the transform is affine. The other defined positioning facility implements a coordinate transform, which is really of unbounded complexity (e.g., could perform bowtie correction on raw satellite image, could implement a photogrammetric transform based on a few supplied parameters). Intermediate complexity stuff is just missing, which I found to be wierd. Positioning stuff does not resample: it specifies the mapping between grid cells and external CRS. Bryce ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid0944&bid$1720&dat1642 _______________________________________________ Geotools-devel mailing list Geotools-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-devel
