title: What do you call an iterated flood fill algorithm?
body: <p>I have an algorithm that I'm using for my work, but I need a name for it.  I am curious if name exists in the literature for an algorithm of this type.</p>
  
  <p>The algorithm takes a pixelated height map and a starting point s, and returns a modified pixelated height map.  For each pixel p in the returned height map, p is the value of lowest height you <em>must</em> pass through to get from s to p.</p>
  
  <p>Example, consider the "peak" image in Matlab:  <code>imagesc(peak)</code> <img src="https://i.stack.imgur.com/Fou4P.png" alt="Peak Image from Matlab">.</p>
  
  <p>And use the pixel (20,20) as the seed, then this modified height map I am describing looks like this:  <img src="https://i.stack.imgur.com/vxgT9.png" alt="enter image description here">.</p>
  
  <p>I had called this a flood fill algorithm, until my colleagues pointed out that flood fills are typically binary maps.  So, Ive taken to calling this a "graduated flood fill" algorithm.</p>
  
  <p>We have not found this operation defined in the literature.  Any suggestions?</p>