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NHDPlus Versioning System
Effective with data released after June 1, 2006, NHDPlus has a dual versioning system.
Both the data model schema and the data content are versioned. NHDPlus download .ZIP
files each contain the version information in the filename in the form of "Vss_cc",
where ss is the schema version and cc is the data content version. Each component can
be versioned and distributed without the need to re-release all components. For example,
at any given time, both NHDPlus10LV02_03_CatShape.zip and NHDPlus10LV01_02_NHD.zip
might be available for download. In this example, the Catchment shape file has schema
version 02 and data content version 03 while the NHD component has schema version 01
and data content version 02.
The NHDPlus download site will contain the most recent version for each component. When
a change in NHDPlus affects more than one component, the new version of all affected
components will be made available at the same time. Therefore, users can be assured that
all components on the download site, regardless of their indicated versions, are
compatible with each other. Please see the NHDPlus User Guide for more information.
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