[R] Scatterplot3d-proposal

[Duncan Murdoch]

On 1/23/2007 8:29 AM, Atte Tenkanen wrote:
>> 
>> 
>> Duncan Murdoch wrote:
>> > On 1/23/2007 6:38 AM, Atte Tenkanen wrote:
>> >> Hi,
>> >>
>> >> Does somebody know if there is some trick to betoken the 
>> starting points ("on the floor") of the vertical lines in 
>> scatterplot3d-plots.
>> >> I'd prefer something like that one in the example here
>> >>
>> >> http://users.utu.fi/attenka/proposal3d.jpg
>> >>
>> >> If this is not possible, could this option be added? Sometimes 
>> it is not easy to distinguish objects behind the others and for 
>> instance in this example picture the case nr. 21 is important.
>> > 
>> > scatterplot3d() returns a list of functions which could help with 
>> this, 
>> > in particular the points3d function.
>> 
>> Right, or rather use the returned function xyz.convert, as in:
>> 
>> s3d <- scatterplot3d(1:10, 1:10, 1:10, type="h")
>> s3d$xyz.convert(5, 5, 0)
>> 
>> Now you got coordinates for the point on the plane with z=0 
>> projected 
>> from (5,5,5). It should be easy now to add circles, ellipses or 
>> whatever 
>> you like.
>> 
>> Uwe Ligges
>> 
> 
> Thanks! This seems to work. 
> 
> http://users.utu.fi/attenka/ellipses_in3Db.png
> 
> I only had to change that (5,5,0) to (5,5,0.4). I'm not sure about the reason, is it because of the minimum of x- or y-coordinate in my plot or what?

It is a point in user coordinates, and the bottom of your box has z=0.4.

Duncan Murdoch