Friday, August 16, 2013

Parcel Data Sharing and Ice Cream

The discussions about open data sharing, interoperability, and web services continue to build.  FGDC has published a new portal and there are new open cloud services every day.  What strikes me in these discussions is that at some level we are still resolving data content issues. 

Consider this scenario.  What if parcel data producers, mostly local governments in the U.S. and about 6,000 different local governments, made ice cream instead of parcel data.  Almost everyone loves ice cream but few understand the challenges of making large batches of consistent texture, predictably flavored ice cream.  Locally made ice cream would reflect local tastes and preferences and would evolve with the local needs and demands.

Complicating things is each state would have rules for ice cream packaging, pricing, butter fat content, and maybe even the wafers that could be used for making ice cream cones.  


A consumer might think it is a simple enough question, “I would like some vanilla ice cream.”  The ice cream maker knows there are dozens and dozens of vanilla flavors from plain vanilla to French vanilla with variations including premium churned, fat free, egg free, extra creamy, triple vanilla and many others.  This does not include the branded names for vanilla, which might be New York vanilla, West Coast California vanilla, and Wisconsin true vanilla. 

The mix of the base ice cream, it’s composition, fat content, churning method, and other processing variations plus the vanilla flavoring itself adds much variation and nuance.  For example “natural flavoring” is castoreum, which is a secretion from the castor sacs of adult North American beavers.  “Real vanilla” comes from a Mexican orchid and from subspecies in Madagascar, the West Indies and South America.

Why is it so hard to just get a national vanilla ice cream based on the locally produced ice cream? 

The local ice cream makers who understand the highly nuanced and local needs find it hard to even find the words to explain the variations in vanilla much less the other flavors and types of ice cream cones that are found across the nation.

With over 6,000 producers across the country, it is not unexpected that there are many variations and nuances.  A simple request for a vanilla ice cream cone has many options, so does requesting parcel information. 

The Business Case for a Publication Standard

The purpose of a publication standard is to describe the business uses and needs to support defined applications.  The publication standard is not a random set of features and attributes. In the ice cream example every producer will have variations in vanilla and a host of other flavors but it is unlikely that every producer will have the same combination of flavors.  The publication standard provides a standard data request that each producer completes as best they can.

The publication standard educates the business user as well as the data producer.  It provides a way for the data producer to understand why and how data are used, it limits the number of data elements the data steward has to publish, and it makes the highly variable and highly nuanced operational data easier for the data requester to understand. 

This point was made in the Fair and Equitable article  “Sharing the Data You Have - Getting the Data You Need”, William Craig and Nancy von Meyer, February 2009 p 9.

“Applications that need parcel data but do not understand the finer points of parcel information cannot distinguish between taxable value and market value, much less decipher which value in the local data set contains the necessary value information.”

The National Cadastral Parcel Publication Standard

The Federal Geographic Data Committee (FGDC) Cadastral Subcommittee has a fairly in depth content standard for cadastral data.  It defines the components of land descriptions, cadastral reference systems, legal measurements, corner monumentation, corner coordinate values, rights and interests, and restrictions to rights and interests.  The content standard provides a checklist of information that could be included in a cadastral data system, but it is not an implementation standard and it is not a publication standard. 

Recognizing that the path to implementation required building a publication standard or guideline, the Subcommittee examined several critical national business uses including hurricane and wildland fire response and recovery, economic and mortgage monitoring and response, and energy development and reclamation.  These were business uses that existed across the country and could be used to define a starting national publication guideline.  Each state could add to this base guideline, but a starting base was seen as one path to increased standard implementation.

The resulting guideline includes components for cadastral reference information (Public land Survey System, land Grants, Subdivisions etc.) and parcel information (real estate tax parcels and coming soon federally managed land parcels).   The publication guideline or standard is not intended to be a burden to data stewards, it is intended to enhance communication and encourage the use of this valuable data set in business applications.

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