Hi Gavin,
From my understanding, you would like to plot the data in the columns of 'bothX.txt' using a heatmap. You might be facing an issue due to the heatmap grid as the size of the data is large. You can use the code below for turning the grid off and create a more legible heatmap:
fileID = fopen('bothX.txt','r'); % Open the .txt file
formatSpec = '%f';
sizeA = [2 Inf];
DataPoints = fscanf(fileID, formatSpec, sizeA); % Read the data from the file
fclose(fileID); % Close the file
DataPoints = DataPoints'; % Reformating the data according to match our original data
h = heatmap(DataPoints); % Plot the heatmap
h.GridVisible = 'off'; % Turn the Grid Off
h.YDisplayLabels = nan(size(h.YDisplayData)); % Remove the Y axes' Display Labels
Hope this helps resolve your issue!
