org.apache.lucene.spatial.prefix

## Class HeatmapFacetCounter

- java.lang.Object
- - org.apache.lucene.spatial.prefix.HeatmapFacetCounter

-     public class HeatmapFacetCounter
      extends Object

  Computes spatial facets in two dimensions as a grid of numbers. The data is often visualized as a so-called "heatmap", hence the name.
  WARNING: This API is experimental and might change in incompatible ways in the next release.

- - ### Nested Class Summary

    Nested Classes
    Modifier and Type | Class and Description
    --- | ---
    `static class` | `HeatmapFacetCounter.Heatmap` Response structure

  - ### Field Summary

    Fields
    Modifier and Type | Field and Description
    --- | ---
    `static int` | `MAX_ROWS_OR_COLUMNS` Maximum number of supported rows (or columns).

  - ### Method Summary

    All Methods Static Methods Concrete Methods
    Modifier and Type | Method and Description
    --- | ---
    `static HeatmapFacetCounter.Heatmap` | `calcFacets(PrefixTreeStrategy strategy, IndexReaderContext context, Bits topAcceptDocs, org.locationtech.spatial4j.shape.Shape inputShape, int facetLevel, int maxCells)` Calculates spatial 2D facets (aggregated counts) in a grid, sometimes called a heatmap.

    - ### Methods inherited from class java.lang.Object

      `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- - ### Field Detail

    - #### MAX_ROWS_OR_COLUMNS

          public static final int MAX_ROWS_OR_COLUMNS

      Maximum number of supported rows (or columns).

  - ### Method Detail

    - #### calcFacets

          public static HeatmapFacetCounter.Heatmap calcFacets(PrefixTreeStrategy strategy,
                                                               IndexReaderContext context,
                                                               Bits topAcceptDocs,
                                                               org.locationtech.spatial4j.shape.Shape inputShape,
                                                               int facetLevel,
                                                               int maxCells)
                                                        throws IOException

      Calculates spatial 2D facets (aggregated counts) in a grid, sometimes called a heatmap. Facet computation is implemented by navigating the underlying indexed terms efficiently. If you don't know exactly what facetLevel to go to for a given input box but you have some sense of how many cells there should be relative to the size of the shape, then consider using the logic that `PrefixTreeStrategy` uses when approximating what level to go to when indexing a shape given a distErrPct.
      Parameters:
        `context` - the IndexReader's context
        `topAcceptDocs` - a Bits to limit counted docs. If null, live docs are counted.
        `inputShape` - the shape to gather grid squares for; typically a `Rectangle`. The actual heatmap area will usually be larger since the cells on the edge that overlap are returned. We always return a rectangle of integers even if the inputShape isn't a rectangle -- the non-intersecting cells will all be 0. If null is given, the entire world is assumed.
        `facetLevel` - the target depth (detail) of cells.
        `maxCells` - the maximum number of cells to return. If the cells exceed this count, an
      Throws:
        `IOException`

Copyright © 2000-2019 Apache Software Foundation. All Rights Reserved.