Definitions Revisited

USDA is posting about its data and the brave new world of open data.  Among its goals for the coming year is this:

 " Work with AgGateway on standards and definitions – so “corn” or Common Land Unit (CLU) has the same definition for the data producer and the data users "

Now that aim isn't bad--presumably it can be met by being explicit in the definitions, but I'm reminded of the difficulty in the previous century of getting to common definitions.  To the layman and the big shots a common definition of "corn" between RMA and FSA and NRCS just makes sense.  But when you get into the nitty-gritty there's the qualifications and conditions which entangle the definition into the agency's mission and programs.  A Venn diagram would show circles which overlap maybe 95 percent of the area, but not 100 percent.