On Thu, Mar 3, 2011 at 9:54 PM, George Washington <gws...@hotmail.com>wrote:
> I am new to Matplotlib and am having some problems plotting the following
> set of coordinates (in python 2.6 and Win 7 32)
> This is just a small sample of the data:
>
> Seq.No. x-scale y-scale z-scale
> 01.000000 1579446.055280 5361974.495490 1342.967407
> 02.000000 1579446.646620 5361972.813700 1342.967407
> 03.000000 1579448.047050 5361968.830880 1341.237305
> 04.000000 1579450.992084 5361963.830880 1337.739502
> 05.000000 1579453.937117 5361958.830880 1336.262817
> ...
> ...
>
> with the following outcome:
> (plot3d.png)
>
> *Problem*: while the x-scale is ok and the z-scale looks ok, the y-scale
> is definitely not ok. The numbers in the image are *not* the ones in the
> y-array (I double checked.)
>
George,
This is a known issue where very large axis values were being represented
using an "offset" (much like in 2-d plots with very large axis values). The
problem was that the offset was not displayed for 3d plots. This is
definitely fixed in the latest development branch, but I can't remember if I
fixed it in the 1.0.1 release (probably not).
>
> I also have a number of questons:
> *Question1*: how does one create a label for the z scale? (zlabel is not
> valid)
>
This should be fixed by the next release. Most functions like set_xlim(),
set_ylabel() and such merely call that function for the appropriate axis
object. If a particular function is missing, you can call it yourself doing
something like the following:
ax.zaxis.set_label()
Note that if you have an earlier version of matplotlib, you might have to
do:
ax.w_zaxis.set_label()
> *Queston2*: Is it possible to fill below the line (so it looks like a
> mountain) and how
>
Never tried considered anything like that. Might involve creating a 3D
patch object with some sort of path completion. File a feature request on
the matplotlib tracker here:
http://sourceforge.net/tracker2/?group_id=80706
> *Question3*: Is it possible to traverse sequentially all the points
> plotted in the image so as to make computations (such as distance to the
> next point, etc..).
> The points themselves come from a text file but are not
> in sequence. They are sequenced by being plotted in their right position in
> 3D space.
>
>
I am not exactly sure what you mean, but there is a nice data structure that
I use to do efficient data operations on spatial data called KDTrees, which
can be found in scipy:
http://docs.scipy.org/doc/scipy/reference/generated/scipy.spatial.KDTree.html
I hope that is helpful.
Ben Root
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