Quiver plot of coordinate error with wrong arrow lengths

I’m working on a quiver plot that represents coordinate error in images.
However, the magnitude of the vectors is not being represented correctly: for example, some small erros are being draw as bigger lines.
The magnitudes seems to be calculated correctly, but ‘idx’ is always 0 or 1, although there are 4 magnitude classes; also, the lengths of arrows are wrong in the figures.

I’m plotting 5 figures, but magnitude thresholds are calculated considering the set of images to generate a common legend.

% data

x1 = xlsread(‘DSC03765.xlsx’,1,’A14:A614′);
y1 = xlsread(‘DSC03765.xlsx’,1,’B14:B614′);
errorx1 = xlsread(‘DSC03765.xlsx’,1,’E14:E614′);
errory1 = xlsread(‘DSC03765.xlsx’,1,’F14:F614′);

x2 = xlsread(‘DSC03765.xlsx’,2,’A14:A614′);
y2 = xlsread(‘DSC03765.xlsx’,2,’B14:B614′);
errorx2 = xlsread(‘DSC03765.xlsx’,2,’E14:E614′);
errory2 = xlsread(‘DSC03765.xlsx’,2,’F14:F614′);

x3 = xlsread(‘DSC03765.xlsx’,3,’A14:A614′);
y3 = xlsread(‘DSC03765.xlsx’,3,’B14:B614′);
errorx3 = xlsread(‘DSC03765.xlsx’,3,’E14:E614′);
errory3 = xlsread(‘DSC03765.xlsx’,3,’F14:F614′);

x4 = xlsread(‘DSC03765.xlsx’,4,’A14:A614′);
y4 = xlsread(‘DSC03765.xlsx’,4,’B14:B614′);
errorx4 = xlsread(‘DSC03765.xlsx’,4,’E14:E614′);
errory4 = xlsread(‘DSC03765.xlsx’,4,’F14:F614′);

x5 = xlsread(‘DSC03765.xlsx’,5,’A14:A614′);
y5 = xlsread(‘DSC03765.xlsx’,5,’B14:B614′);
errorx5 = xlsread(‘DSC03765.xlsx’,5,’E14:E614′);
errory5 = xlsread(‘DSC03765.xlsx’,5,’F14:F614′);

% calculate magnitude

magnitude1 = sqrt(errorx1.^2+errory1.^2);
magnitude2 = sqrt(errorx2.^2+errory2.^2);
magnitude3 = sqrt(errorx3.^2+errory3.^2);
magnitude4 = sqrt(errorx4.^2+errory4.^2);
magnitude5 = sqrt(errorx5.^2+errory5.^2);

magnitude_total = [];

magnitudes = {magnitude1, magnitude2, magnitude3, magnitude4, magnitude5};
% concatenate values of magnitude in one array
for i = 1:length(magnitudes)
magnitude_total = vertcat(magnitude_total, magnitudes{i});
end

% calculate min and max magnitude
mag_res = 0.05;
magnitudelim = [ …
floor(min(magnitude_total)/mag_res) …
ceil(max(magnitude_total)/mag_res) …
]*mag_res;

% define a color map
n_colors = 4;
cmap = jet(n_colors);

% calculate the magnitude thresholds
mthresholds = linspace(magnitudelim(1),magnitudelim(2),n_colors+1);

% plot function
function plot_image(x, y, errorx, errory, magnitude, mthresholds, cmap, magnitudelim, n_colors, img_title)
figure
hold on

% for each color, find the indicies of the magnitudes at this color level
for ii = 1:n_colors
idx = magnitude >= mthresholds(ii) & magnitude < mthresholds(ii+1);
% generate an arrow of the corresponding color
quiver(x(idx), y(idx), errorx(idx), errory(idx), 0.5, ‘Color’, cmap(ii,:));
end

% set up the colorbar
colormap(cmap);
colorbar();
caxis(magnitudelim);

xlim([0 2836])
ylim([0 2778])

title(img_title);
hold off
end

% plot all figures
plot_image(x1, y1, errorx1, errory1, magnitude1, mthresholds, cmap, magnitudelim, n_colors, ‘570nm’);
plot_image(x2, y2, errorx2, errory2, magnitude2, mthresholds, cmap, magnitudelim, n_colors, ‘525nm’);
plot_image(x3, y3, errorx3, errory3, magnitude3, mthresholds, cmap, magnitudelim, n_colors, ‘850nm’);
plot_image(x4, y4, errorx4, errory4, magnitude4, mthresholds, cmap, magnitudelim, n_colors, ‘490nm’);
plot_image(x5, y5, errorx5, errory5, magnitude5, mthresholds, cmap, magnitudelim, n_colors, ‘550nm’);I’m working on a quiver plot that represents coordinate error in images.
However, the magnitude of the vectors is not being represented correctly: for example, some small erros are being draw as bigger lines.
The magnitudes seems to be calculated correctly, but ‘idx’ is always 0 or 1, although there are 4 magnitude classes; also, the lengths of arrows are wrong in the figures.

I’m plotting 5 figures, but magnitude thresholds are calculated considering the set of images to generate a common legend.

% data

% calculate magnitude

magnitude_total = [];

% calculate min and max magnitude
mag_res = 0.05;
magnitudelim = [ …
floor(min(magnitude_total)/mag_res) …
ceil(max(magnitude_total)/mag_res) …
]*mag_res;

% define a color map
n_colors = 4;
cmap = jet(n_colors);

% calculate the magnitude thresholds
mthresholds = linspace(magnitudelim(1),magnitudelim(2),n_colors+1);

% plot function
function plot_image(x, y, errorx, errory, magnitude, mthresholds, cmap, magnitudelim, n_colors, img_title)
figure
hold on

% set up the colorbar
colormap(cmap);
colorbar();
caxis(magnitudelim);

xlim([0 2836])
ylim([0 2778])

title(img_title);
hold off
end

% plot all figures
plot_image(x1, y1, errorx1, errory1, magnitude1, mthresholds, cmap, magnitudelim, n_colors, ‘570nm’);
plot_image(x2, y2, errorx2, errory2, magnitude2, mthresholds, cmap, magnitudelim, n_colors, ‘525nm’);
plot_image(x3, y3, errorx3, errory3, magnitude3, mthresholds, cmap, magnitudelim, n_colors, ‘850nm’);
plot_image(x4, y4, errorx4, errory4, magnitude4, mthresholds, cmap, magnitudelim, n_colors, ‘490nm’);
plot_image(x5, y5, errorx5, errory5, magnitude5, mthresholds, cmap, magnitudelim, n_colors, ‘550nm’); I’m working on a quiver plot that represents coordinate error in images.
However, the magnitude of the vectors is not being represented correctly: for example, some small erros are being draw as bigger lines.
The magnitudes seems to be calculated correctly, but ‘idx’ is always 0 or 1, although there are 4 magnitude classes; also, the lengths of arrows are wrong in the figures.

I’m plotting 5 figures, but magnitude thresholds are calculated considering the set of images to generate a common legend.

% data

% calculate magnitude

magnitude_total = [];

% calculate min and max magnitude
mag_res = 0.05;
magnitudelim = [ …
floor(min(magnitude_total)/mag_res) …
ceil(max(magnitude_total)/mag_res) …
]*mag_res;

% define a color map
n_colors = 4;
cmap = jet(n_colors);

% calculate the magnitude thresholds
mthresholds = linspace(magnitudelim(1),magnitudelim(2),n_colors+1);

% plot function
function plot_image(x, y, errorx, errory, magnitude, mthresholds, cmap, magnitudelim, n_colors, img_title)
figure
hold on

% set up the colorbar
colormap(cmap);
colorbar();
caxis(magnitudelim);

xlim([0 2836])
ylim([0 2778])

title(img_title);
hold off
end

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