The
authoritative source for parcel data depends on what type of parcel data. For tax parcels, the most commonly aggregated
and distributed data set, the real estate taxing authority that created them
(see who builds parcel data) is the most widely accepted authoritative
source. For legal survey boundaries, the land survey record is the
authoritative source. But do we really
mean fitness for use?
Authority,
authoritative, and authoritativeness always seem to trigger a fairly robust
discussion, especially around cadastral data.
A few dictionary-based definitions may be a good starting point. The following are gathered from various
dictionaries and papers on this topic.
Authority
and Authoritative - Authoritative is
recognized as trustworthy, competent, reliable, and true. Supported by an authority. In the context of public agencies it is the
legal responsibility provided by a legislative body to conduct business for the
public good.
Official
- A person invested with the authority of an office.
Authoritative
Data – For
publicly sourced data these are officially recognized data that can be
certified by the public provider, such as a certified tax roll, and is provided
by an authoritative source.
Authoritative
Data Source –
An information technology (IT) term used by system designers to identify a
system process that assures the veracity of data sources. All geospatial data
providers should follow these IT processes. The data may be original or it may
come from one or more external sources all of which are validated for quality
and accuracy.
Authoritative
Source – An
entity that is authorized by a legal authority to develop or manage data for a
specific business purpose. The data this entity creates is authoritative
data. Authoritative data comes directly from the creator or authoritative
source. It is the most current and accurate and has
been vetted according to official rules and policy. The data has a known
accuracy and lineage and can be verified and certified by data stewards in the
authoritative source. In some terminology this is termed the “primary” data source
or the “official” data source.
Authorization – The result of an act by a legislative or
executive body that declares or identifies an agency or organization as an authoritative source or grants the rights to
an agency to act, such as an authorization to manage land or collect
information.
Data Steward – An organization within an authoritative source
that is charged with the collection and maintenance of authoritative data. The
term data steward is often confounded with the term authoritative
source. A data steward may be a designated point for the assembly and
aggregation of data from authoritative sources.
Trusted Source and Trusted Data – A service provider
or agency that publishes data from a number of authoritative sources.
These publications are often compilations and subsets of the data from more
than one authoritative source. It is “trusted” because there is an
“official process” for compiling the data from authoritative sources and the limitations, currency,
and attributes are known and documented.
In the discussions around a national parcel data set or national
parcel data sources, It appears that a discussion and agreement on fitness for
use, including some standard or consistent wording or perhaps even categories
of fitness for use would come in handy. We
need to answer questions such as “are the values on this parcel from my local
assessor and are they official or certified?” or “can I rely on these
annexation boundaries as the official boundaries?” or “are these boundaries
attached to their definitive source document?” Standard metadata templates
include a field for describing intended use or use limitations. Perhaps it is time to look at providing
consistency for these fields.
Many local and state published data sets have a disclaimer that
limit the liability of the publisher and provide some general fitness for use such
as “not to be used for land transaction legal descriptions”. A data publisher can never know all possible
uses for a data set. It is likely that
some or most data sets will be misused.
Disclaimers try to limit the liability of the data producer if the data
are put to some unintended or wholly inappropriate use or relied upon to
support an application for which the data was never intended. This is completely understandable.
As parcel data moves to more open formats and publication, perhaps
this is a good time for the community to have some discussions and consensus on
expected fitness for use. This would be
more exact and less misunderstood than using terms like authoritative or
trusted.
