Ah, interesting. Just to check I've understood this correctly: 1) A coverage represented internally by a grid (e.g. numerical model output, digital photo or satellite image) is a type of DiscreteCoverage in ISO19123 (perhaps a DiscreteGridPointCoverage)?
2) For a DiscreteCoverage, if I ask for a value at a point that doesn't correspond exactly with a grid point I will get the value from the nearest grid point (i.e. nearest-neighbour interpolation). Or do I actually get null? 3) However, in GeoTools, the DiscreteCoverages are not implemented. The GridCoverage2D class does not implement ISO19123 interfaces but it is effectively a discrete coverage that performs nearest-neighbour interpolation. 4) If I want bilinear (or bicubic or anything else) interpolation then I need to take my GridCoverage2D and somehow convert it to an Interpolator2D. How do I do this? Another question: Is it possible to have different interpolation methods in different directions (e.g. nearest-neighbour in the horizontal, linear in the vertical)? Cheers, Jon On Wed, Jun 11, 2008 at 4:20 PM, Martin Desruisseaux <[EMAIL PROTECTED]> wrote: > > Andy Turner a écrit : >> I think a continuous coverage is one where for any location a value is >> obtained by interpolation and that for a discrete coverage the value at any >> point is known directly. (The distinction, continuous or discrete is nothing >> to do with the values attributed to the coverage.) > > Yes it is also my understanding. It GeoTools implementation, GridCoverage2D > (without subclassing) would be a discrete coverage (minus tricky boundary > issues > like the ones you mentioned) while Interpolator2D would be a continuous > coverage. But at this time GeoTools does not implement ISO interfaces that > way. > However this is something we would like to do in the future. > > Martin > > --~--~---------~--~----~------------~-------~--~----~ > You received this message because you are subscribed to the Google Groups > "GeoShaver" group. > To post to this group, send email to [EMAIL PROTECTED] > To unsubscribe from this group, send email to [EMAIL PROTECTED] > For more options, visit this group at > http://groups.google.co.uk/group/geoshaver?hl=en-GB > -~----------~----~----~----~------~----~------~--~--- > > -- -------------------------------------------------------------- Dr Jon Blower Tel: +44 118 378 5213 (direct line) Technical Director Tel: +44 118 378 8741 (ESSC) Reading e-Science Centre Fax: +44 118 378 6413 ESSC Email: [EMAIL PROTECTED] University of Reading 3 Earley Gate Reading RG6 6AL, UK -------------------------------------------------------------- ------------------------------------------------------------------------- Check out the new SourceForge.net Marketplace. It's the best place to buy or sell services for just about anything Open Source. http://sourceforge.net/services/buy/index.php _______________________________________________ Geotools-gt2-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/geotools-gt2-users
