fractal dimensions calcuation

[Zhanlf0226]

hi everyone,

I wanna calculate the mineral fractal dimensions in a mylonitic sample, strangely, the result is <1 by using three linear fit methods, it means somewhere wrong. Enclosed is my data and my code. Could you help me check it what's the problem? Thank you very much!

code:
%% Import Script for EBSD Data
% This script was automatically created by the import wizard. You should
% run the whole 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 = {...
'notIndexed',...
crystalSymmetry('321', [4.9 4.9 5.5], 'X||a*', 'Y||b', 'Z||c*', 'mineral', 'Quartz-new', 'color', [0.53 0.81 0.98]),...
crystalSymmetry('12/m1', [8.6 13 7.2], [90,116,90]degree, 'X||a', 'Y||b*', 'Z||c', 'mineral', 'Orthoclase', 'color', [0.56 0.74 0.56]),...
crystalSymmetry('12/m1', [8.3 13 7.1], [90,116.05,90]degree, 'X||a', 'Y||b*', 'Z||c', 'mineral', 'Anorthoclase', 'color', [0.85 0.65 0.13])};

% plotting convention
setMTEXpref('xAxisDirection','east');
setMTEXpref('zAxisDirection','outOfPlane');

%% Specify File Names
% path to files
pname = 'D:\matlab2023b\mtex-5.11.2\mtex-5.11.2\dong_sample_2024\GL2208-1';

% which files to be imported
fname = [pname '\trailleft.cpr'];

%% Import the Data
% create an EBSD variable containing the data
ebsd = EBSD.load(fname, CS, 'interface', 'crc', 'convertEuler2SpatialReferenceFrame');

%% Compute grains and smooth
[grains, ebsd.grainId] = calcGrains(ebsd, 'angle', 5*degree);
grains = grains(~grains.isBoundary);
grains = smooth(grains, 5);
figure
plot(grains)
title('Grains before removing not indexed data')

%% Plot shape factor
figure
plot(grains, grains.shapeFactor)
mtexColorbar('title','shape factor')
title('Shape Factor Mapping after removing not indexed data and boundary grains')

%%

% Extract grains of 'Quartz-new'
grainsQ = grains('Quartz-new');

% Check data range
disp(['Equivalent Radius range: ', num2str(min(grainsQ.equivalentRadius)), ' to ', num2str(max(grainsQ.equivalentRadius))]);
disp(['Perimeter range: ', num2str(min(grainsQ.perimeter)), ' to ', num2str(max(grainsQ.perimeter))]);

% Remove grains with zero or negative equivalent radius or perimeter
validIdx = (grainsQ.equivalentRadius > 0) & (grainsQ.perimeter > 0);
grainsQ = grainsQ(validIdx);

% Log-transform the data
logEquivalentRadius = log(grainsQ.equivalentRadius);
logPerimeter = log(grainsQ.perimeter);

% Plot scatter plot
figure
scatter(grainsQ.equivalentRadius, grainsQ.perimeter)
xlabel('Equivalent Radius')
ylabel('Perimeter')

% Set axes to logarithmic scale
set(gca, 'XScale', 'log', 'YScale', 'log')
xlim([10, 10^4])
ylim([10^2, 10^5])

% 1. Linear fit using polyfit
p = polyfit(logEquivalentRadius, logPerimeter, 1);
hold on
plot([10,10^4],exp(p(2) + p(1) * log([10,10^4])),'LineWidth',3)
hold off

% Set legend
legend('Data', 'Polyfit', 'Fitlm', 'Regress')

% Output fractal dimensions
fractalDimension_polyfit = p(1);
trailleft.zip