"surface" plots

Posted on 2008-11-09 11:29 By Dirk (

21)

Categories:

How do I ...? with Maple (Student)

Hi,

I tried to get a 3D "surface" plot (comapreable to a matrix surface plot or matrixplot) of a list in the form:

[[xi,yi,zi],....]

where xi are the x-data, yi are the y-data and zi are some velocity data. Unfortunately I found only the possibility to draw a pointplot3d. Maybe anybody can help me.

Thanks

Dirk

View 6629_data2.mw on MapleNet or Download 6629_data2.mw
View file details Download 6629_data2.xls
View file details

surfdata

Comment on 2008-11-09 14:23 from jakubi ( Maple Rating 4

943)

may be what you are looking for.

PS. However, it sounds like the output of

surfdata(data2, axes = boxed);

is not the intended surface. This seems better:

PLOT3D(POLYGONS(data2),STYLE(PATCHNOGRID),AXESSTYLE(BOX),
ORIENTATION(6.,68.));

polygonplot3d

Comment on 2008-11-09 16:08 from Dirk (

21)

Thanks for the hint with polygonplot3d! I am still a bit displeased with the "incomplete" borders. Restructuring the basic data source did not work, but I did not want to add any data points.

incomplete borders

Comment on 2008-11-09 18:33 from jakubi ( Maple Rating 4

943)

Observing the combination of points and polygons:

with(plots):
with(plottools):
data2:=...
p1:=pointplot3d(data2, color = red):
p2:=polygon(data2):
display([p1,p2],axes=boxed,orientation=[74,60.]);

I think that there are two problems here:

1. Some points are not joined by segments, making the borders ragged.

2. Some polygons are not correctly painted (probably related to a longstanding bug), paradoxically making the borders a bit less ragged.

Not what you want

Comment on 2008-11-10 11:35 from DJ Clayworth ( Maple Rating 3

206)

I don't believe that either of these are doing what you want to be done.

surfdata considers the data to be an nx3 array of z values and plots each z values as though on an nx3 grid.

polygonplot3d considers the data to be a single polygon, with the data defining the vertices. Since the data are not ordered correctly for a polygon (and don't in fact define a single polygon) you will get a polygon that overlaps itself in many places and occupies space that it should not. It's only because the data you have are roughly in a plane that the polygon looks like anything useful at all.

David Clayworth Maplesoft GUI Developer

so,

Comment on 2008-11-10 13:02 from jakubi ( Maple Rating 4

943)

how would you do it?

I have expected that the code generating the polygons were capable to optimize and avoid overlappings.

A useful package maybe.....

Comment on 2008-11-13 09:24 from Paul Weiss (

11)

I am currently facing exactly the same problem, that is to plot a surface which is defined at arbitrary points in the xy plane.

I have written a package that takles the problem by first performing a Delaunay triangulation in the xy plane, and by then plotting the resulting triangles. You will find it attached, together with a sample worksheet including your data. I hope you will find it useful.

(please remove the initial numbers befor using them)

Please be warned that this is my first try at package writing, and that there is no documentation up to now.

Paul

View 8933_data2.mw on MapleNet or Download 8933_data2.mw
View file details

Download 8933_Surfplot.lib
View file details

Download 8933_Surfplot.ind
View file details

but only available within Maple 12

Comment on 2008-11-18 16:48 from Dirk (

21)

your suggestion is working well, but unfortunately the "Surfplot" Package is only available within Maple 12!

Some precision

Comment on 2008-11-19 02:33 from Paul Weiss (

11)

Could you be a little more specific?

Does the attached package only work under Maple 12? If yes, I shall investigate why.

However, it would help me if you knew more precisely what instruction, routine, etc... is causing an issue.

Regards,

Paul

I work with Maple 11, which

Comment on 2008-11-19 09:46 from Dirk (

21)

I work with Maple 11, which does not include the Surfplot-package. I have checked this in the package library. I thik this is a new feature of Maple 12.

After executing your worksheet (8933_data2.mw), Maple 11 returns the following error message after the command "with(Surfplot)":

"Error, invalid input: with expects its 1st argument, pname, to be of type {package, module}, but received Surfplot"

Therefore following commands of your worksheet does not work in Maple 11:

RemoveEquals
Triangulate

Regards, Dirk

Something is wrong

Comment on 2008-11-19 11:09 from jakubi ( Maple Rating 4

943)

Paul,

I have inspected these library files and experimented installing them, but they seem wrong. In particular, I do not see any entry in the Surfplot.ind file. Could you check whether these files work for you?