Quiver Plot not plotting all data

Hi, I've created code to demonstrate a simple rankine vortex and initially I thought my code was wrong but I have since done the problem in excel, imported it to MATLAB and still the graph I am getting showing is omitting the majority of the data. I'm using a quiver plot and would expect arrows for every point on the grid.

I have pasted below the code to import the text file with the data inside (attached). I have also attached the plot I get and what I expect to get (roughly). I would really really appreciate any help. Thanks in advance

 filename = 'C:\Users\TC\Documents\MATLAB\Free_Forced_Vorticity\ExcelOutput.txt';
 delimiter = '\t';

 formatSpec = '%f%f%f%f%f%f%f%f%[^\n\r]';

 %%Open the text file.
 fileID = fopen(filename,'r');

 %%Read columns of data according to format string.
 dataArray = textscan(fileID, formatSpec, 'Delimiter', delimiter,  'ReturnOnError', false);

 %%Close the text file.
 fclose(fileID);

 %%Allocate imported array to column variable names
i = dataArray{:, 1};
j = dataArray{:, 2};
x = dataArray{:, 3};
y = dataArray{:, 4};
r = dataArray{:, 5};
utheta = dataArray{:, 6};
u = dataArray{:, 7};
v = dataArray{:, 8};

 %%Clear temporary variables
 clearvars filename delimiter formatSpec fileID dataArray ans;

 %%Graphing Data
 quiver(x,y,u,v)
 grid on

Answer 1

[Star Strider]

They’re all plotted, but they vary considerably in length so some don’t show up. If you artificially normalise them, they all do.

Without changing any of your other code, replace the ‘quiver’ call with this to see them:

arwlen = hypot(u, v);                   % Arrow Lengths

figure(1)
quiver(x, y, u./arwlen, v./arwlen);
grid

Apparently, Excel (or whatever you plotted ‘Expected Graph’ with) doesn’t care about the length variation. MATLAB does.