datafu.pig.geo

Class HaversineDistInMiles

java.lang.Object

org.apache.pig.EvalFunc<T>

datafu.pig.util.ContextualEvalFunc<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;
 

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.pig.EvalFunc

org.apache.pig.EvalFunc.SchemaType

Field Summary

Fields

Modifier and Type	Field and Description
static double	EARTH_RADIUS

Fields inherited from class org.apache.pig.EvalFunc

log, pigLogger, reporter, returnType

Constructor Summary

Constructors

Constructor and Description
HaversineDistInMiles()

Method Summary

Modifier and Type	Method and Description
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 datafu.pig.util.ContextualEvalFunc

getContextProperties, getInstanceName, getInstanceProperties, onReady, setUDFContextSignature

Methods inherited from class org.apache.pig.EvalFunc

allowCompileTimeCalculation, finish, getArgToFuncMapping, getCacheFiles, getInputSchema, getLogger, getPigLogger, getReporter, getSchemaName, getSchemaType, getShipFiles, isAsynchronous, progress, setInputSchema, setPigLogger, setReporter, 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