public long getId(double x, double y) {
    double down = (extentMax - y) / binSize;
    double over = (x - extentMin) / binSize;

    return ((long) down * numCols) + (long) over;
  }
Gets bin ID from a point.

@param x
@param y
@return
ql/src/java/org/apache/hadoop/hive/ql/udf/esri/BinUtils.java