Gnuplot histogram 3d
<p>I'm looking for a way to plot histograms in 3d to produce something like this figure <a href="http://www.gnuplot.info/demo/surface1.17.png" rel="nofollow noreferrer">http://www.gnuplot.info/demo/surface1.17.png</a> but where each series is a histogram.</p>

<p>I'm using the procedure given here <a href="https://stackoverflow.com/a/19596160">https://stackoverflow.com/a/19596160</a> and <a href="http://www.gnuplotting.org/calculating-histograms/" rel="nofollow noreferrer">http://www.gnuplotting.org/calculating-histograms/</a> to produce histograms, and it works perfectly in 2d. 
Basically, the commands I use are </p>

<pre><code>hist = 'u (binwidth*(floor(($2-binstart)/binwidth)+0.5)+binstart):(1) smooth freq w boxes
plot 'data.txt' @hist
</code></pre>

<p>Now I would just like to add multiple histograms in the same plot, but because they overlap in 2d, I would like to space them out in a 3d plot.</p>

<p>I have tried to do the following command (using above procedure)</p>

<pre><code>hist = 'u (1):(binwidth*(floor(($2-binstart)/binwidth)+0.5)+binstart):(1) smooth freq w boxes
splot 'data.txt' @hist
</code></pre>

<p>But gnuplot complains that the z values are undefined.</p>

<p>I don't understand why this would not put a histogram along the value 1 on the x-axis with the bins along the y-axis, and plot the height on the z-axis.</p>

<p>My data is formatted simply in two columns:</p>

<pre><code>Index   angle
0       92.046      
1       91.331      
2       86.604      
3       88.446      
4       85.384      
5       85.975      
6       88.566      
7       90.575      
</code></pre>

<p>I have 10 files like this, and since the values in the files are close to each other, they will completely overlap if I plot them all in one 2d histogram. Therefore, I would like to see 10 histograms behind each other in a sort of 3d perspective. </p>