Mapping a GeoShape field

An extension to the concept of point is the shape. Elasticsearch provides a type that facilitates the management of arbitrary polygons: the GeoShape.

Getting ready

You need an up-and-running Elasticsearch installation as we described in the Downloading and installing Elasticsearch recipe in Chapter 2, Downloading and Setup.

To be able to use advanced shape management, Elasticsearch requires two JAR libraries in its classpath (usually the lib directory):

• Spatial4J (v0.3)

• JTS (v1.13)

How to do it

To map a geo_shape type, a user must explicitly provide some parameters:

• tree: This is the name of the PrefixTree implementation: geohash for GeohashPrefixTree and quadtree for QuadPrefixTree (default geohash)

• precision: This is used instead of tree_levels to provide a more human value to be used in the tree level. The precision number can be followed by the unit, that is, 10m, 10km, 10miles, and so on

• tree_levels: This is the maximum number of layers to be used in the prefix tree

• distance_error_pct...