On Mon, Apr 12, 2010 at 12:04 PM, David MacMahon <dav...@astro.berkeley.edu> wrote: > Sounds (and looks!) interesting, Hez! > > Is this global transform applied before, after, or instead of the "pltr" > type transformations? > > It looks like the global transform function has the same signature as the > "pltr" transform functions so that the predefined pltr1, pltr2, etc. > functions can be used as global transformation functions. Do you envision > this global transform capability supplanting the individual pltr parameter > in the functions that currently support it? > > Thanks, > Dave >
Dave, I'm glad others think that this is an interesting addition. I certainly agree! The global transform is applied after the "pltr"-type transforms, While the signatures are the same, I'm not sure that pltr[0-2] could be used with plstransform in a simple manner. The intent of the function is closer to that of the mapform parameter in plmap and plmeridians where the transform is from unprojected world coordinates -> projected world coordinates. If I recall correctly, the pltr* functions transform data-grid coordinates ((0, 0) to (nx -1, ny - 1)) to world coordinates so they may not work with plstransform exactly as they are, at least not in all cases. They do, however, still play an important role. Which leads to your question on supplanting per-function pltr parameters. I think these parameters could be replaced, but I see some value to keeping them around, at least for some PLplot functions. For plmap and plmeridians, the mapform function parameter could be completely replaced by plstransform as the mapform function performs a (longitude, latitude) -> plplot world coordinate transformation. The replacement is not as simple for plshades, plcont, plimagefr and similar functions. In some cases, you may still want to map the data grid values to specific coordinates and then project those coordinates in a particular way. A meteorological example might be mapping satellite-based precipitation observations to (longitude, latitude) with a pltr function and then transforming (longitude, latitude) to a particular map projection. These projections could be combined in to one step, but splitting them up allows for a slightly more modular design. Replace (longitude, latitude) with (RA, Dec), "precipitation" with "M51" and "map" with "sky" for a contrived astronomical example :-) Hez ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Plplot-devel mailing list Plplot-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-devel
