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Core Science Analytics and Synthesis - USGS-NPS Vegetation Characterization Program

Standards and Protocols
Program Methodology

The USGS-NPS Vegetation Characterization Program methodology is based on a set of nationally defined standards, as well as standards defined within the framework of the program. Use of standards facilitates effective resource stewardship by ensuring compatibility and widespread use of the vegetation information throughout the National Park Service, as well as by other federal and state agencies.

Development and documentation of standards and protocols is one of the core activities for the program’s scientists. The following documents, describing protocols and standards for data collection and analysis, are the program’s foundation:

  • 12-step Guidance for NPS Vegetation Inventories – all NPS staff, cooperators and contractors follow these steps in the process of developing and delivering inventory products. The only exception is parks in Alaska, which are mapped at lower resolution, using a different approach, because of the scale, remoteness, and logistical issues.

  • FGDC National Vegetation Classification Standard – this federal standard, also known as USNVC, was established by the Vegetation Subcommittee of the Federal Geographic Data Committee (FGDC) and is used by the program to classify vegetation. The most recent version of the standard was adopted in 2008. Parks, where vegetation inventories were completed before 2008, used the 1997 standard. You can see a comparison of 1997 and 2008 classifications for a specific vegetation type. Both versions, as well as all formal documentation about the standard, can be found on the FGDC Web site.

  • Field Methods for Vegetation Mapping – this document describes the planning process and field methods used to sample and accurately map the National Vegetation Classification units across all participating parks. It was prepared as a result of a study, which reviewed the scientific basis for vegetation sampling and proposed a standardized field methodology, which was adopted for the program.

  • Thematic Accuracy Assessment Procedures. Version 2 – this 2010 NPS report is a revision and an update of the 1994 guidance on thematic accuracy assessment for the program. It (1) provides the conceptual framework for thematic accuracy assessment within the program, (2) describes minimal requirements for the process, and (3) gives “best practices” guidance, including an acceptable range of procedural variations as alternative procedures.


  • Methodology for Assessing the Utility of Existing Data for Vegetation Mapping – this methodology was developed to allow the use of previously gathered vegetation data for the program, as it can offer great cost savings. The suitability of an existing data set for vegetation mapping is determined by identifying and assessing seven key data quality components, associated with it.

  • Glossary – commonly used terms in the Vegetation Characterization Program.

Nationally Defined Standards Used in the Program:
  • FGDC National Vegetation Classification Standard - used by the program to classify vegetation. For the USNVC Hierarchy Explorer and new information about USNVC visit http://usnvc.org/.

  • FGDC Spatial Data Transfer Standard - enables blind transfer of information between different hardware/software environments without loss of contextual information. All program spatial data are available in this format.

  • FGDC Metadata Standard – used to create metadata file for each spatial dataset in the program. A metadata file associated with a dataset describes how the dataset was developed, what projection was used, what the attributes mean, and provides other important contextual information for the data in a human readable format.

  • National Map Accuracy Standards - horizontal positional accuracy in all spatial databases, produced by the program meets this standard at the 1:24,000 scale.

  • Integrated Taxonomic Information System (ITIS) - program uses this on-line, scientifically credible system for taxonomic information to ensure the plant names are consistent and meet the highest scientific standards.
Program Defined Standards:
  • Classification Accuracy: Each vegetation map class will meet or exceed 80% accuracy at the 90% confidence level. The classification accuracy will be established by the program accuracy assessment protocols.

  • Minimum Mapping Unit: The minimum mapping unit is 0.5 hectares.