st: Calculate Distance between Properties within Portfolios

["S. McKay Price" <smp210@lehigh.edu>]

Hello,

I'm trying to calculate the distance, in miles or kilometers, between 
all possible pairwise combinations of properties within a given 
portfolio.  Is there an efficient way to structure the data to 
accomplish this?

My data include numerous portfolios (roughly 200), each with a unique 
portfolio identifier (portfolio_id).  And, there are multiple properties 
within each portfolio (180 on average), where each property has a unique 
property identifier (property_id).   I have latitude and longitude 
coordinates in decimal form for each property (e.g. 42.270873 
-83.726329) for use in a command such as -geodist- from SSC, or 
something similar.  The data are organized as follows:

portfolio_id property_id latitude longitude
1 1 lat lon
1 2 lat lon
1 3 lat lon
...
2 1 lat lon
2 2 lat lon
2 3 lat lon
etc...

Any suggestions?  Thank you for your consideration.

McKay

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