optimizing for an XLink

I'm trying to build an XML solution for some weather data we have and I'm
looking for some help in optimizing the source data. 

I have forecast and current conditions for some 3000+ cities. That weather
data is organized by stations, some cities use the same station for both
forecast and current conditions and some stations are used by a number of
cities. Instead of storing my data with the forecast and current condition
information for each city included in the source document, I'm going to keep
it in an external file and use an XLink to join them up. Each of the cities
and each of the stations is going to have an id that will be used in the
link. I know how to do all that but my question relates to optimizing the
source order of my data for optimum speed. Does it matter, or should I have
my data listed with the IDs in sort order. With thousands of records, I want
to have the source data in an optimum order. 

Thanks
Adam van den Hoven


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