Editorial changes

docs/notes/EntropyMetricForDataCompressionCaseStudies.html

@@ -55,7 +55,8 @@ <h1>Introduction</h1>
                     <a href="https://en.wikipedia.org/wiki/Huffman_coding">Huffman coding</a> and
                     <a href="https://en.wikipedia.org/wiki/Deflate">Deflate</a>. It also supports the use
                     of experimental or application-specified data compression techniques, but those are
-                    outside the scope of this article.</p>
+                    outside the scope of this article. For more information on Gridfour's data compression
+					implementations, see our article on <a href="GridfourDataCompressionAlgorithms.html">algorithms for raster data compression</a>.</p>
 
                 <h2>The entropy calculation</h2>
                 <p>The entropy values reported in the discussion below is based on Claude Shannon's first-order
@@ -194,15 +195,16 @@ <h2>Statistical variation over the domain of a data set</h2>
             Deflate:  64 % of all tiles
             Huffman:  36 %   ""     ""
         Average entropy of source data as selected for method:
-            Deflate:   4.89 bits/elevation
-            Huffman:   3.35   ""    ""
+            Deflate:   6.16 bits/elevation
+            Huffman:   5.83   ""    ""
                 </pre>
 
                 <p>The fact that the Huffman method is selected so often may seem counterintuitive
                     because the Deflate technique usually out performs Huffman by a substantial margin.
-                    In this case, it appears that Huffman can produce smaller output than Deflate
-                    for subsets of the data product where the source entropy is low and the tendency
-                    of the data to exhibit repetitive patterns is reduced.</p>
+                    The reason for this unexpected result is not clear at this time and will
+                    be the subject of further investigation.
+                    Since Deflate relies on patterns in the data, it is likely that Huffman is
+                    preferred in tiles where repetitive patterns were absent or difficult to detect.</p>
 
                 <p>For more information on the data compression logic used to produce these results, see
                   <a href="https://gwlucastrig.github.io/GridfourDocs/notes/GridfourDataCompressionAlgorithms.html">