 geo_point field does not support GeoJson which can be a PITA if your data is in such a format. Indexing it as a geo_shape is an option but very wasteful.
server/src/test/java/org/elasticsearch/search/geo/GeoPointShapeQueryTests.java
@Override
    protected void createMapping(String indexName, String fieldName, Settings settings) throws Exception {
        XContentBuilder xcb = XContentFactory.jsonBuilder()
            .startObject()
            .startObject("properties")
            .startObject(fieldName)
            .field("type", "geo_point")
            .endObject()
            .endObject()
            .endObject();