anchor.diff:  number followed by an optional distance unit. Valid distance units
   include: `in`, `inch`, `yd`, `yard`, `mi`, `miles`, `km`, `kilometers`,
   `m`,`meters`, `cm`,`centimeters`, `mm`, `millimeters`.
  -| `meters`
  +| `50m`
   
   |`tree_levels` |Maximum number of layers to be used by the PrefixTree.
   This can be used to control the precision of shape representations and
  
positive.code: longitude interleaved. So the longer the hash, the more precise it is.
  Each character added to the geohash represents another tree level and
  adds 5 bits of precision to the geohash. A geohash represents a
  rectangular area and has 32 sub rectangles. The maximum amount of levels
  in Elasticsearch is 24.
  * QuadPrefixTree - Uses a
  http://en.wikipedia.org/wiki/Quadtree[quadtree] for grid squares.
  Similar to geohash, quad trees interleave the bits of the latitude and
  longitude the resulting hash is a bit set. A tree level in a quad tree
  represents 2 bits in this bit set, one for each coordinate. The maximum
  amount of levels for the quad trees in Elasticsearch is 50.
  
  [[spatial-strategy]]
  [float]
  
negative.code: may use the `precision` parameter instead. However, Elasticsearch only
  uses the tree_levels parameter internally and this is what is returned
  via the mapping API even if you use the precision parameter.
  | various
  
  |`strategy` |The strategy parameter defines the approach for how to
  represent shapes at indexing and search time. It also influences the
  