Mashup Macro - Add Latitude/Longitude

This macro 'geotags' (i.e. adds latitude and longitude values) the mashup based upon any type of geographic information including zip code, city/state/country, or places of interest.

One note: To get this macro to work, you must first register 'http://ws.geonames.org/postalCodeSearch?postalcode=20816&country=US' as a Presto service and name it 'geonames'.  (You can read more about the geonames service at http://www.geonames.org.) 

<?xml version="1.0" encoding="UTF-8"?>
   <macro xmlns="http://www.jackbe.com/2008-03-01/EMMLSchema" 
      xmlns:myfunc="java:com.jackbe.jbp.jems.client.EMMLPrestoFunctions" name="LatLon">
   <presto-meta name="macrotype">user</presto-meta>

   <input default="06700" name="zipcode" type="string"  /> 
   <input default="MX" name="country" type="string"  />     
   <output name="result" type="document"  />

   <variables>
      <variable name="lat" type="string"  />

      <variable name="lng" type="string"  />

      <variable name="preliminary" type="string"  />
   </variables>      

   <invoke inputvariables="zipcode,country" operation="getData" outputvariable="preliminary" service="geonames"  />

   <assign fromexpr="$preliminary//lat/string()" outputvariable="lat"  /> 
   <assign fromexpr="$preliminary//lng/string()" outputvariable="lng"  />

<!-- Building the output -->

   <constructor outputvariable="result">
   <LatLon>
      <lat>{$lat}</lat>

      <lon>{$lng}</lon>
   </LatLon>
   </constructor>
</macro>

This macro is based upon an EMML program, 'Mashup Code Sample - Mashup to convert a zipcode into Lat/Long data via a REST service', by MDC Member Igo.