Solr Spatial Search

心海恋歌

　　三种fieldType：
　　LatLonType
　　SpatialRecursivePrefixTreeFieldType（RPT）
　　BBoxField
　　
　　Spatial Filters:
　　geofilt
　　&q=*:*&fq={!geofilt sfield=store}&pt=45.15,-93.85&d=5
　　all the results within the circle of the given radius around the initial point
　　bbox
　　&q=*:*&fq={!bbox sfield=store}&pt=45.15,-93.85&d=5.
　　all the results in the box
　　
　　specify large distErrPct value , the filter will run faster
　　
　　arbitrary rectangle
　　RPT support
　　
solr post filter
　　&q=...mykeywords...&fq=...someotherfilters...&fq={!geofilt cache=false cost=100}&sfield=store&pt=45.15,-93.85&d=5
　　
　　distance function queries
　　geodist,dist,hsin,sqedist
　　
　　geodist
　　sort result by distance asc
　　&q=*:*&fq={!geofilt}&sfield=store&pt=45.15,-93.85&d=50&sort=geodist asc
　　return distance as the document score
　　&q={!func}geodist()&sfield=store&pt=45.15,-93.85&sort=score+asc
　　
　　More examples
　　
　　use as a sub-query to expand the search results
　　Here we will query for results in Jacksonville, Florida, or within 50 kilometers of 45.15,-93.85 (near Buffalo, Minnesota):
　　&q=*:*&fq=(state:"FL" AND city:"Jacksonville") OR {!geofilt}&sfield=store&pt=45.15,-93.85&d=50&sort=geodist()+asc
　　
　　facet by distance
　　To facet by distance, you can use the Frange query parser:
　　&q=*:*&sfield=store&pt=45.15,-93.85&facet.query={!frange l=0 u=5}geodist()&facet.query={!frange l=5.001 u=3000}geodist()
　　There are other ways to do it too, like using a {!geofilt} in each facet.query.
　　
　　boost nearest results
　　&q.alt=*:*&fq={!geofilt}&sfield=store&pt=45.15,-93.85&d=50&bf=recip(geodist(),2,200,20)&sort=score desc
　　
SpatialRecursivePrefixTreeFieldType (abbreviated as RPT)
　　Solr 4's new spatial field offers several new features and improvements over LatLonType:

• Query by polygons and other complex shapes, in addition to circles & rectangles
  
• Multi-valued indexed fields
  
• Ability to index non-point shapes (e.g. polygons) as well as point shapes
  
• Rectangles with user-specified corners that can cross the dateline
  
• Multi-value distance sort and score boosting (warning: non-optimized)
  
• Well-Known-Text (WKT) shape syntax (required for specifying polygons & other complex shapes)
  

　　RPT schema
　　class
　　distErrPct指中心点与边界距离的精确度，【0.0---0.5】越小越精确，索引慢，占用磁盘越多，查询慢，反之则反
　　geo 默认值为true，将应用经纬度坐标，数学模型是一个球体，false则是二维的xy坐标
　　maxDistErr 定义索引数据的详细程度，默认一米，只比0.000009 degrees小一点，这个设置用来在内部计算恰当的maxLevels
　　maxLevels 设置索引数据的最大格子深度，更直观的是通过指定maxDistErr来计算恰当的maxLevels
　　name
　　prefixTree 定义spatial grid的实现，prefixTree把一个地域范围映射成一个grid，每一个grid被分解成一系列下一级的sub grid ，如果geo=false默认的prefix tree是geohash，否则是quad，geohash有32个孩子grid，quad有4个。
　　spatialContextFactory 如果使用多边形，则需要指定它的实现（com.spatial4j.core.context.jts.JtsSpatialContextFactory），设置autoIndex=true提升多边形的性能　　
　　units 现在只能是degrees，是用来计算maxDistErr的，1degree大约111.2千米
　　worldBounds 如果geo=false则需要指定worldBounds，format ： ENVELOPE(minX, maxX, maxY, minY)
　　samples



more info about this http://wiki.apache.org/solr/SolrAdaptersForLuceneSpatial4

BBoxField
　　BBoxField索引一个矩形，支持通过boundary box 查询　　
　　samples






　　The latter is the only way to choose a predicate other than Intersects.  For example:
　　&q={!field f=bbox}Contains(ENVELOPE(-10, 20, 15, 10))
　　Now to sort the results by one of the relevancy modes, use it like this:
　　&q={!field f=bbox score=overlapRatio}Intersects(ENVELOPE(-10, 20, 15, 10))
　　You can also use&debug=results to see useful score computation info.