update function information

src/ucar/unidata/data/grid/GridUtil.java

@@ -8887,7 +8887,8 @@ public static UnionSet glyphsToMap(GriddedSet domainSet, List glyphs) throws Exc
     }
 
     /**
-     * Process medianFilter
+     * Process medianFilter mean filtering is simply to replace each pixel value
+     * in an image with the mean (average) value of its neighbors, including itself
      *
      * @param field
      * @param window_lenx default value is 10
@@ -9241,7 +9242,8 @@ public static float[] medianFilterOrg(float[] A, int lenx, int leny, int window_
     }
 
     /**
-     * Process classifier
+     *  A classifier in machine learning is an algorithm that automatically orders or
+     *  categorizes data into one or more of a set of “classes.”
      *
      * @param field
      * @param classifierStr input string of classifier