Issue with pole figure

[Qinghua Wang]

Hi all:

  I have a very dumb question which have puzzled me for a while. I would appreciate if someone can point it out for me.

  For plotting the pole figures, I would assume for one single grain, there should be three projections points of the [100], [010] and [001] directions, corresponding to the three Eulers angles. Therefore, for a five-grain case, I expect to see fifteen projection points on the pole figure. But in the pole figure I plotted with the MTEX software, I can only see five projection points but I can not understand what the issue is. Can somebody help me to check my problem? Thanks a lot.

  The pole figure and input texture file are attached.

  Regards,

     Qinghua Wang

[Luiz Fernando Morales]

Deae Quinghua

The triplet of Euler angles are the three angles necessary to describe the rotation between crystal and external reference frame. There are many definitions of Euler angles in the liteerature and the used in metx is the one by bunge (1982). To use euler angles one have to define a right hand cartesian system in crystall coordinates, and for cubic, tetragobal and orthorhombic minerals, this is normal lattive vectord a,b, c 100, 010 and 001  (sorry thr square brackets are missing). In otherbless symmetric systems, you may have different options because a,b and c are not orthogonal. This has notthing to do with the fact with the pole figures you chose, you are going to see point repwtition in these pole figurs if they are for exaplme in a cubic mineral, but not in an orthorrombic phase.

Hope this clarifies a bit, there are some nice crystallography books that can be hwlpful if you want

Best

Luiz

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[Qinghua Wang]

Hi Luiz:

  Thanks for your explanation. 

  I am still a little bit confused. From my understanding of your explanation, I believe what you mean is in my attached pole figure, it is only the projection points in the 100 direction, so there will be only five points. There will also be other projection points for the five grains in the 010 and 001 directions. Am I understanding it correctly?

  Another question is: what does the legend on the pole figure mean? I did not see the explanation of it on the MTEX manual.

  Thanks.

  Qinghua Wang

[Thomas Simm]

what's your code look like? have you included hold on?

I get many more when I do:

Eul =[  101.9800  145.0300  249.4400;

  131.7300   86.2600  229.2900;

   13.5800  153.6800  314.4000;

   88.9800  124.1200  115.1600;

  132.8100  105.7200  180.6900];

cs = crystalSymmetry('cubic');

figure(33)

for n=1:4

    

    o2 = orientation('Euler',Eul(n,:),cs);

    plotPDF(o2,Miller({0,0,1},cs,'Annotations','grid'))

    hold on

end

[Luiz Fernando Morales]

Hi thomas

Thanks for that, i suspect thr definition os CS is the issue here, maybe he has something thay is not cubic, but i  curious to see the code

Best

Luiz

[Qinghua Wang]

Hi Tom:

  I directly use the MTEX toolbox. I first ran the install_mtex.m file, then I imported the pole figure data using the Import Wizard. After completion, the following code was automatically generated:

%% Import Script for PoleFigure Data

%

% This script was automatically created by the import wizard. You should

% run the whoole script or parts of it in order to import your data. There

% is no problem in making any changes to this script.

%% Specify Crystal and Specimen Symmetries

% crystal symmetry

CS = crystalSymmetry('112/m', [1 1 1], [90,90,90]*degree, 'X||a', 'Y||b', 'Z||c', 'color', 'light blue');

% specimen symmetry

SS = specimenSymmetry('1');

% plotting convention

setMTEXpref('xAxisDirection','east');

setMTEXpref('zAxisDirection','outOfPlane');

%% Specify File Names

% path to files

pname = 'E:\CPFE_Modeling\twoelesetsdy';

% which files to be imported

fname = [pname '\texture_processed_One grainoneor.txto'];

%% Specify Miller Indice

h = { ...

  Miller(1,0,0,CS),...

  };

%% Import the Data

% create a Pole Figure variable containing the data

pf = loadPoleFigure(fname,h,CS,SS,'interface','generic',...

  'ColumnNames', { 'Polar Angle' 'Azimuth Angle' 'Intensity' 'Background' 'Defocussing' 'Defocussing Background'}, 'Columns', [1 2 3 4 5 6]);

figure

plot(pf,'MarkerSize',4)

mtexColorbar

  I can not figure out what is the problem with my current code. Can you be kind enough to tell me what my problem is? I am not sure why I am using the import wizard correctly.

  Thanks.

   Qinghua Wang

[Qinghua Wang]

Hi Luiz:

  I have attached the code automatically generated by MTEX Toolbox. Please take a look at it at your convenience. I would appreciate your help.

  Thanks.

  Qinghua Wang

[Ralf Hielscher]

Hi Quang,

for me it seems you data file contains 5 orientations each consisting of three Euler angles which you can import using

ori = loadOrientation('texture-5.txti','CS',crystalSymmetry('112/m'))

after importing the orientations you can plot pole figures of them by

plotPDF(ori,Miller(1,0,0,ori.CS))

What you did on the other hand was to interpret these data as pole figure data. Pole figure data consist of a tuple of polar coordinates and an intensity. Hence, MTEX has interpreted your first two Euler angles as polar coordinates of the pole figure position and the third Euler angle as the intensity. This is what you get to see in you plot - points at the positions of the first two Euler angles colored according to the third Euler angle.

For importing data you should always ask yourself what kind of data do I have - not what I want to visualize. If you have pole figure data - import them as pole figure data, if you have EBSD data import them as EBSD data. Do not mix this.

Ralf.

[Qinghua Wang]

Hi Ralf:

  Thanks a lot for your explanation. This clarifies a lot. 

  What about if I want to plot the recalculated pole figures? I believe that will be a better visualization method for me. I have attempted several times according to the manual but it did not work.

  Thanks.

  Qinghua Wang

[Ralf Hielscher]

How did you imagine to compute an ODF from 4 orientations? Though it can be done by

odf = calcODF(ori)

plotPDF(odf,Miller(1,0,0,odf.CS)

Ralf.

[Qinghua Wang]

Hi Ralf:

  Thanks a lot for the help. The code works well. I will try to play with more orientations in the future.

  Best,

    Qinghua Wang