Example usage for org.apache.lucene.spatial.prefix.tree QuadPrefixTree MAX_LEVELS_POSSIBLE

Introduction

In this page you can find the example usage for org.apache.lucene.spatial.prefix.tree QuadPrefixTree MAX_LEVELS_POSSIBLE.

Prototype

int MAX_LEVELS_POSSIBLE

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Usage

From source file:org.codelibs.elasticsearch.common.geo.GeoUtils.java

License:Apache License

/**
 * Calculate the number of levels needed for a specific precision. Quadtree
 * cells will not exceed the specified size (diagonal) of the precision.
 * @param meters Maximum size of cells in meters (must greater than zero)
 * @return levels need to achieve precision
 *//*from ww w  . j a v a  2  s  .  com*/
public static int quadTreeLevelsForPrecision(double meters) {
    assert meters >= 0;
    if (meters == 0) {
        return QuadPrefixTree.MAX_LEVELS_POSSIBLE;
    } else {
        final double ratio = 1 + (EARTH_POLAR_DISTANCE / EARTH_EQUATOR); // cell ratio
        final double width = Math.sqrt((meters * meters) / (ratio * ratio)); // convert to cell width
        final long part = Math.round(Math.ceil(EARTH_EQUATOR / width));
        final int level = Long.SIZE - Long.numberOfLeadingZeros(part) - 1; // (log_2)
        return (part <= (1L << level)) ? level : (level + 1); // adjust level
    }
}

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From source file:org.elasticsearch.common.geo.GeoUtils.java

License:Apache License

/**
 * Calculate the number of levels needed for a specific precision. Quadtree
 * cells will not exceed the specified size (diagonal) of the precision.
 * @param meters Maximum size of cells in meters (must greater than zero)
 * @return levels need to achieve precision  
 *///from  w  w  w  .  ja v a  2s . com
public static int quadTreeLevelsForPrecision(double meters) {
    assert meters >= 0;
    if (meters == 0) {
        return QuadPrefixTree.MAX_LEVELS_POSSIBLE;
    } else {
        final double ratio = 1 + (EARTH_POLAR_DISTANCE / EARTH_EQUATOR); // cell ratio
        final double width = Math.sqrt((meters * meters) / (ratio * ratio)); // convert to cell width
        final long part = Math.round(Math.ceil(EARTH_EQUATOR / width));
        final int level = Long.SIZE - Long.numberOfLeadingZeros(part) - 1; // (log_2)
        return (part <= (1l << level)) ? level : (level + 1); // adjust level
    }
}

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