Lucene.net proximity搜索

Question

有沒有人擁有lucene.net index經緯度值的經驗，然後根據距單點距離返回一組有序的結果？

Lucene.Net.Spatial庫對我有所幫助嗎？

Answer 1

晚會有點晚，但是，空間圖書館是開始的地方。其背後的基礎是：

1）添加緯度和長域到您的文檔

doc.Add(new Field("Latitude", 
        NumericUtils.DoubleToPrefixCoded(Latitude), 
        Field.Store.YES, Field.Index.NOT_ANALYZED)); 

doc.Add(new Field("Longitude", 
        NumericUtils.DoubleToPrefixCoded(Longitude), 
        Field.Store.YES, Field.Index.NOT_ANALYZED)); 

2）創建粒度的每一層，你的搜索需要支持繪圖儀

IProjector projector = new SinusoidalProjector(); 
var ctp = new CartesianTierPlotter(0, projector, 
            Fields.LocationTierPrefix); 
StartTier = ctp.BestFit(MaxKms); 
EndTier = ctp.BestFit(MinKms); 

Plotters = new Dictionary<int, CartesianTierPlotter>(); 
for (var tier = StartTier; tier <= EndTier; tier++) 
{ 
    Plotters.Add(tier, new CartesianTierPlotter(tier, 
              projector, 
              Fields.LocationTierPrefix)); 
} 

3）使用您的繪圖儀爲您的文檔編制索引

private static void AddCartesianTiers(double latitude, 
             double longitude, 
             Document document) 
{ 
    for (var tier = StartTier; tier <= EndTier; tier++) 
    { 
     var ctp = Plotters[tier]; 
     var boxId = ctp.GetTierBoxId(latitude, longitude); 
     document.Add(new Field(ctp.GetTierFieldName(), 
         NumericUtils.DoubleToPrefixCoded(boxId), 
         Field.Store.YES, 
         Field.Index.NOT_ANALYZED_NO_NORMS)); 
    } 
} 

隨着你的索引文件，你可以移動到建立一個查詢。本例中使用ConstantScoreQuery，但你可以換是出於對你的遠程評分：

/* Builder allows us to build a polygon which we will use to limit 
* search scope on our cartesian tiers, this is like putting a grid 
* over a map */ 
var builder = new CartesianPolyFilterBuilder(Fields.LocationTierPrefix); 

/* Bounding area draws the polygon, this can be thought of as working 
* out which squares of the grid over a map to search */ 
var boundingArea = builder.GetBoundingArea(Latitude, 
       Longitude, 
       DistanceInKilometres * ProductSearchEngine.KmsToMiles); 

/* We refine, this is the equivalent of drawing a circle on the map, 
* within our grid squares, ignoring the parts the squares we are 
* searching that aren't within the circle - ignoring extraneous corners 
* and such */ 
var distFilter = new LatLongDistanceFilter(boundingArea, 
            DistanceInKilometres * KmsToMiles, 
            Latitude, 
            Longitude, 
            ProductSearchEngine.Fields.Latitude, 
            ProductSearchEngine.Fields.Longitude); 

/* We add a query stating we will only search against products that have 
* GeoCode information */ 
var query = new TermQuery(new Term(Fields.HasGeoCode, 
            FieldFlags.HasField)); 

/* Add our filter, this will stream through our results and 
* determine eligibility */ 
masterQuery.Add(new ConstantScoreQuery(distanceFilter), 
       BooleanClause.Occur.MUST); 

所有這一切都從一個博客帖子我只是寫，而在尋找類似的問題而採取的。你可以看到它在http://www.leapinggorilla.com/Blog/Read/1005/spatial-search-in-lucenenet