datafu.pig.geo
Class HaversineDistInMiles

java.lang.Object
  org.apache.pig.EvalFunc<T>
      datafu.pig.util.SimpleEvalFunc<java.lang.Double>
          datafu.pig.geo.HaversineDistInMiles

public class HaversineDistInMiles
extends SimpleEvalFunc<java.lang.Double>

Computes the distance (in miles) between two latitude-longitude pairs using the Haversine formula.

Example:

 -- input is a TSV of two latitude and longitude pairs
 input = LOAD 'input' AS (lat1 : double, long1 : double, lat2 : double, long2 : double);
 output = FOREACH input GENERATE datafu.pig.geo.HaversineDistInMiles(lat1, long1, lat2, long2) as distance;
 

Field Summary

static double

EARTH_RADIUS

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

HaversineDistInMiles()

Method Summary

java.lang.Double	call(java.lang.Double lat1, java.lang.Double lng1, java.lang.Double lat2, java.lang.Double lng2)
org.apache.pig.impl.logicalLayer.schema.Schema	outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input) Override outputSchema so we can verify the input schema at pig compile time, instead of runtime

Methods inherited from class datafu.pig.util.SimpleEvalFunc

exec, getReturnType

Methods inherited from class org.apache.pig.EvalFunc

finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getSchemaName, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, setUDFContextSignature, warn

Methods inherited from class java.lang.Object

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

Field Detail

EARTH_RADIUS

public static final double EARTH_RADIUS

See Also:

Constant Field Values

Constructor Detail

HaversineDistInMiles

public HaversineDistInMiles()

Method Detail

call

public java.lang.Double call(java.lang.Double lat1,
                             java.lang.Double lng1,
                             java.lang.Double lat2,
                             java.lang.Double lng2)

outputSchema

public org.apache.pig.impl.logicalLayer.schema.Schema outputSchema(org.apache.pig.impl.logicalLayer.schema.Schema input)

Description copied from class: SimpleEvalFunc

Override outputSchema so we can verify the input schema at pig compile time, instead of runtime

Overrides:

outputSchema in class SimpleEvalFunc<java.lang.Double>

Parameters:

input - input schema

Returns:

call to super.outputSchema in case schema was defined elsewhere