Hello, Thank you for your answer.
> Since your pattern of points is confined to a circular area (and rather > complete within that area), my suggestion is to try using polar coordinates > throughout. Now example 21 obviously uses rectangular coordinates for > plgriddata, but I presume plgriddata should work just as it is for any > two-dimensional coordinate system. Yes, this should work. I will have a look. Not sure if there is the time to implement this. Perhaps it is easier to calculate the rays which intersect with the eye glass in exactly the points of a rectangular grid. > Furthermore, example 16's last page (see > http://plplot.sourceforge.net/examples-data/demo16/x16.05.png) shows > plshades can be used with any two-dimensional coordinate system. Ok, this looks good. This example shows me that it is possible to draw a graph of a circle without filling the whole rectangle. >> Is there a way to use the DTLI algorithm to get a kind of data like in >> http://m21s26.vlinux.de/math/gsg.png? > > I think yes. Once you get plgriddata and plshades working for polar > coordinates it should be a simple matter to use plbox to make a rectangular > box around the circular area created by plshades. You can arrange the plbox > call so the tick marks on the box are for rectangular coordinates > corresponding to the polar coordinates used for plshades. Puh... I don't understand this at this moment. I'll have to dive into it. Converting it to polar coordinates, ok. This should be no problem. Then I would get (I hope so...) a regular grid in polar coordinates. But if I convert it back it may not be regular, in x-y, right? Hm, not sure how to implement this, but it should be possible in any way. Thank you and regards Paul. ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Plplot-general mailing list Plplot-general@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/plplot-general
