**Glossary**

**USGS-NPS Vegetation Mapping Program**

**June 2001**

This is not an exhaustive glossary of all vegetation classification or
vegetation mapping terms, but is a useful list of definitions for many
of the important and/or ambiguous terms used in the USGS-NPS Vegetation
Mapping Program.

For detailed glossaries of different aspects of the program see

> 1\) <http://biology.usgs.gov/npsveg/aa/sect10.html> for definitions of
> terms related to accuracy assessment,
>
> 2\) The FGDC Vegetation Subcommittee glossary at
> <http://www.fs.fed.us/research/fgdc/fgdcindex2.htm> for definitions of
> terms related to vegetation classification and the NVCS,

3)  "Datums And Projections: A Brief Guide " at for an introduction to
    datums and projections, and

4)  <http://www.esa.org/vegweb/vegstds_v2.htm> developed by the
    Ecological Society of America in its "An Initiative For A
    Standardized Classification Of Vegetation In The United States"
    (Draft).

**7.5-minute Quadrangle** -- A USGS paper map product at 1:24,000 scale
covering 7.5 minutes of latitude and 7.5 minutes of longitude. Features
shown include elevation contours, roads, railroads, water bodies,
building, urban developments, and wetlands. This is a basic layer of
information for many ecological and natural resource applications. An
automated version of the 7.5-minute quadrangle is called the digital
raster graphic or DRG. Informally known as 7.5-minute quad.

**Accuracy** -- The closeness of results of observations, computations,
or estimates to the true values or to values that are accepted as being
true (ASP, 1984). In the USGS-NPS Vegetation Mapping Program there are
two aspects of accuracy: thematic and positional accuracy.

**Accuracy Assessment** -- The process of determining the positional and
thematic accuracy of the spatial vegetation community data. This is an
independent process performed after the vegetation mapping and
classification is complete. See "Producing rigorous and consistent
accuracy assessment procedures ", Anonymous, 1996 at
<http://biology.usgs.gov/npsveg/aa/index.html> for more information.

**Accuracy Assessment Point** -- A location where accuracy assessment
data are collected. See "Producing rigorous and consistent accuracy
assessment procedures ", Anonymous, 1996 at
<http://biology.usgs.gov/npsveg/aa/index.html> for more information.

**Aerial Photography** -- Analog imagery taken from an airplane. In this
program the optical axis is oriented perpendicular to the earth's
surface so that the film is parallel to the surface being photographed.
(also Vertical Aerial Photography). A sequence of aerial photographs
will overlap so the photos can be used in stereoscopic analysis (stereo
pairs). The overlap is referred to as 'endlap' (top-to-bottom area in
common, same flightline) and 'sidelap' (side-to-side area in common,
different flightlines) (Portions from ASP, 1984). Aerial photography
used in the program is 9 inch by 9 inch vertical, stereoscopic, color or
color infrared photography.

**Alliance** -- A physiognomically uniform group of associations sharing
one or more diagnostic (dominant, differential, indicator, or character)
species that, as a rule, are found in the uppermost stratum of the
vegetation (FGDC). This is the second finest level in the National
Vegetation Classification Standard hierarchy. See the table under USNVC.

**Anderson Classification System** -- A land cover/land use
classification system developed for use with remote sensing systems in
the 1970's adopted for the USGS-NPS Vegetation Mapping Program to map
cultural land cover (Anderson et al. 1976).

+----------------------------+-----------------------------------------+
| **Level I**                | **Level II**                            |
+----------------------------+-----------------------------------------+
| 1\. Urban or Built-up Land | Residential                             |
+----------------------------+-----------------------------------------+
|                            | Commercial and Services                 |
+----------------------------+-----------------------------------------+
|                            | Industrial                              |
+----------------------------+-----------------------------------------+
|                            | Transportation, Communications, and     |
|                            | Utilities                               |
+----------------------------+-----------------------------------------+
|                            | Industrial and Commercial Complexes     |
+----------------------------+-----------------------------------------+
|                            | Mixed Urban or Built-up Land            |
+----------------------------+-----------------------------------------+
|                            | Other Urban or Built-up Land            |
+----------------------------+-----------------------------------------+
| 2\. Agricultural Land      | Cropland and Pasture                    |
+----------------------------+-----------------------------------------+
|                            | Orchard, Groves, Vineyards, Nurseries,  |
|                            | and                                     |
|                            |                                         |
|                            | Ornamental Horticultural Areas          |
+----------------------------+-----------------------------------------+
|                            | Confined Feeding Operations             |
+----------------------------+-----------------------------------------+
|                            | Other Agricultural Lands                |
+----------------------------+-----------------------------------------+
| 5\. Water (nonvegetated    | Streams and Canals                      |
| portion)                   |                                         |
+----------------------------+-----------------------------------------+
|                            | Lakes                                   |
+----------------------------+-----------------------------------------+
|                            | Reservoirs                              |
+----------------------------+-----------------------------------------+
|                            | Bays and Estuaries                      |
+----------------------------+-----------------------------------------+
| 7\. Barren Land            | Dry Salt Flats                          |
+----------------------------+-----------------------------------------+
|                            | Beaches                                 |
+----------------------------+-----------------------------------------+
|                            | Sandy Areas other than Beaches          |
+----------------------------+-----------------------------------------+
|                            | Strip Mines, Quarries, and Gravel Pits  |
+----------------------------+-----------------------------------------+
|                            | Transitional Areas                      |
+----------------------------+-----------------------------------------+
|                            | Mixed Barren Lands                      |
+----------------------------+-----------------------------------------+
| Perennial Snow or Ice      | Perennial Snowfields                    |
+----------------------------+-----------------------------------------+
|                            | Glaciers                                |
+----------------------------+-----------------------------------------+

> Note: This is not the complete Anderson Level II Classification. Areas
> of natural vegetation are classified under the NVCS.

**Association** -- The finest level of the National Vegetation
Classification Standard. The association is a physiognomically uniform
group of vegetation stands that share one or more diagnostic (dominant,
differential, indicator, or character) overstory and understory species.
These elements occur as repeatable patterns of assemblages across the
landscape, and are generally found under similar habitat conditions
(FGDC). See table under USNVC an example. Within the program association
is the preferred term, but it is also synonymous with community,
community type, plant community, type, vegetation community, and
vegetation type.

**Association for Biodiversity Information** (ABI) -- A non-profit
organization dedicated to developing and providing knowledge about the
world\'s natural diversity. In cooperation with the Natural Heritage
Network, ABI collects and develops authoritative information about the
plants, animals, and ecological communities of the Western Hemisphere.
ABI maintains databases to support the United States National Vegetation
Classification System (USNVCS) and the plot data that it is based on.
ABI cooperates closely with the program to develop vegetation community
classifications.

**Attribute** -- (digital data) A numeric, text, or image data field in
a relational database table (such as a GIS) that describes a spatial
feature (point, line, polygon, cell) (ESRI, 1994).

**Automate** -- The process of entering data into a computer. Synonymous
with digitize.

**Base Map** -- The source or control from which all spatial data are
developed and geo-referenced to. Photo interpreted data are transferred
to a base to rectify and register the data. For this program base maps
consist of USGS DOQ's or specially made orthophotos.

**Bureau of Reclamation** (BOR, USBOR) -- A U.S. Department of Interior
agency, created in 1902, charged with developing irrigation and
hydropower projects in 17 Western States in an environmentally and
economically sound manner in the interest of the American public. The
Remote Sensing and GIS Group of the BOR is managing several park
projects for the USGS-NPS Vegetation Mapping Program.

**Biological Resources Division** (BRD) -- A USGS division where the
Center for Biological Informatics is located. The BRD mission is to work
with others to provide the scientific understanding and technologies
needed to support the sound management and conservation of our Nation\'s
biological resources. Also known as the Biological Resources Discipline.

**Center for Biological Informatics** (CBI) -- A USGS Science Center.
CBI serves as the operating agent for the National Biological
Information Infrastructure. In addition, CBI manages the USGS-NPS
Vegetation Mapping Program along with other national data collection
programs that complement and strengthen its role within the NBII.

**Class** -- The level in the National Vegetation Classification
Standard hierarchy based on the structure of the vegetation and
determined by the relative percentage of cover and the height of the
dominant, uppermost life forms (Grossman et al. 1998). See the table
under USNVC.

**Classification Accuracy** -- How closely the map classes match the
vegetation communities found on the landscape. This is determined by
accuracy assessment protocols. See "Producing rigorous and consistent
accuracy assessment procedures" at
<http://biology.usgs.gov/npsveg/aa/index.html> for more information.
Also see producer's and user's accuracy.

**Community** -- An assemblage of species that co-occur in defined areas
at certain times and have the potential to interact with one anther
(Grossman et al., 1998). May also refer to an association in the USNVC,
but this is not preferred

**Community Element Global** (CEGL) -- ABI's unique identifier code to a
vegetation association (community) in their central biodiversity
database; also known as Elcode.

**Community Type** -- See type.

**Complex** -- A group of associations that are not distinguishable from
one another on aerial photography and so are grouped into a map unit.
Compare with mosaic.

**Confusion Matrix** -- See Contingency Table

**Contingency Table** -- A table that compares mapped data with ground
data to determine accuracy. The "known" classes derived from accuracy
assessment plots are compared to the classes derived from photo
interpretation. The results are then tabulated in the form of a
contingency table to determine the degree of misclassification that has
occurred between classes. Also referred to as error matrix, confusion
matrix, or misclassification matrix. For an example of a contingency
table see <http://biology.usgs.gov/npsveg/scbl/aa_matrix.html>.

**Coordinate System** -- A reference system to represent horizontal
and/or vertical locations and distances on a map. The geographic
coordinate system is the latitude and longitude with respect to a
reference spheroid. A local coordinate system is one that is not aligned
with the Earth's surface. Most coordinate systems are based on
projections of the earth's surface to a plane. All spatial data in the
program are represented in the Universal Transverse Mercator (UTM)
coordinate system.

**Cover** -- The area of ground covered by the vertical projection of
the aerial parts of plants of one or more species. (FGDC, 1997).

**Cover Type** -- A designation based upon the plant species forming a
plurality of composition within a given area (e.g., Oak-Hickory) (FGDC,
1977). Also refers to an alliance or group of alliances in the USNVC.

**Coverage** -- A file format used by Arc/Info software for vector
spatial data.

**Cowardin Classification** -- Wetland classification system commonly
referred to as the Cowardin classification, after the first author. This
is the FGDC standard for wetland classification. (Cowardin, 1979).

**Cultural Vegetation** -- Vegetation planted or actively maintained by
humans such as annual croplands, orchards, and vineyards. Contrast with
natural vegetation. (Grossman et al., 1998).

**Crosswalk** -- Relationship between the elements of two classification
systems. For example, there is a crosswalk between map classes and units
of the NVCS. This relationship is often shown in a look up table (LUT).

**Datum** -- A mathematical model that describes the size and shape of
the ellipsoid (the Earth is not a sphere but an ellipsoid distorted by
rotation about its axis, with the globe bulging at the equator and
flattened at the poles). The flattening is not uniform around the Earth
due to the influence of the continents location (Snyder, 1982). Using
the wrong datum in relation to geographic coordinates can result in
errors of hundreds of meters in position. This Program uses the North
American Datum (NAD) of 1983 or NAD83.

**Density** -- Density is the relationship between the area covered by
the overstoy of a vegetation community and the total area of a polygon
in which the community is found. One of the physiognomic modifiers
classified in the USGS-NPS Vegetation Mapping Program. Density in map
units is classified as Closed/Continuous \> 60 %, Discontinuous 40% -
60%, Dispersed 25% - 40%, Sparse 10% - 25%, Rare 2% - 10%. Compare with
pattern and height.

**Diagnostic Species** -- Used to evaluate \[i.e., diagnose\] an area,
or site, for some characteristic. For example, the presence and relative
density of a *Vaccinium stamineum var. stamineum* (gooseberry)
understory existing beneath a canopy of chestnut oak, black oak, and
Virginia pine indicates that the site is xeric (or dry). The oaks and
pines can inhabit a wide range of sites, wet to dry. But the gooseberry
understory is the indicator of a drier habitat (which is probably due to
a combination of factors including: soil type, slope, aspect, elevation,
and site history). Also known as indicator species. (FGDC, 1997).

**Dichotomous Field Key** -- A document that identifies vegetation
communities on the basis of exclusive characteristics. An example of
exclusive characteristics is forested versus non-forested. Also known as
vegetation field key and vegetation key. This key is an important
product of each vegetation-mapping project. For an example of a
dichotomous field key visit
<http://biology.usgs.gov/npsveg/agfo/report.pdf#vegkey>.

**Digital Orthophoto Quadrangle** (DOQ) -- USGS digital product derived
from high altitude aerial photography. These digital images are
rectified and registered to locations on the earth and cover
approximately one quarter of a 7.5-minute quadrangle. Also call digital
orthophoto quarter quadrangle, DOQQ, and 3.75-minute DOQ. DOQ's are
often used as base maps to register the photo interpreted data in this
program.

**Digital Raster Graphic** (DRG) -- A scanned image of a paper USGS
topographic map. The geographic information is georeferenced in the UTM
projection with the accuracy and datum of the original map. The minimum
scanning resolution is 250 dots per inch. DRG's are useful layers in a
geographic information system

**Digitize** -- The process of entering data into a computer. There are
several methods of entering spatial data into a computer including
manual digitizing, scan digitizing, and soft copy photogrammetric
methods. Synonymous with automate.

**Division** -- The highest level in the NVCS separating Earth cover
into either vegetated or non-vegetated categories (FGDC, 1997).. See
table under USNVC

**Dominance** -- The extent to which a given species or life form
predominates in a community because of its size, abundance or cover, and
affects the fitness of associated species (FGDC, 1997).

**Dominant Life Form** -- An organism, group of organisms, or taxon that
by its size, abundance, or coverage exerts considerable influence upon
an association\'s biotic (such as structure and function) and abiotic
(such as shade and relative humidity) conditions (FGDC, 1997).

**Ecological Groups** -- Classification of vegetation communities based
on plant assemblages, physical environments, and dynamic processes
useful for conservation planning. These groups are classified on total
floristic composition, physiognomy (vertical structure), spatial pattern
(horizontal structure), physical environment (landscape position/soil),
chemical variables (e.g. soil pH), and disturbance regimes. Some factors
are difficult to measure directly, and must be inferred from knowledge
of species ecology, spatial patterns, and ecological processes. These
groups often occur between the floristic and physiognomic levels of the
NVCS.

**Ecological Society of America** (ESA) -- A non-partisan, nonprofit
organization of scientists founded in 1915 to promote ecological science
and ensure the appropriate use of ecological science in environmental
decision making. The ESA Panel on Vegetation Classification was
constituted to support and facilitate the creation of standardized,
scientifically credible North American vegetation classification.

**Error** -- The distance of results of observations, computations, or
estimates from the true values or to values that are accepted as being
true. Also refers to the misclassification of thematic data. Contrast
with accuracy.

**Error Matrix** -- See contingency table

**Existing Vegetation** - The plant species existing at a location at
the present time. The USGS-NPS Vegetation Mapping Program classifies and
maps existing vegetation. Contrast with potential vegetation (ESA,
1999).

**Federal Geographic Data Committee** (FGDC) -- Coordinates the
development of the National Spatial Data Infrastructure (NSDI). The NSDI
encompasses policies, standards, and procedures for organizations to
cooperatively produce and share geographic data. The 17 federal agencies
that make up the FGDC are developing the NSDI in cooperation with
organizations from state, local and tribal governments, the academic
community, and the private sector. The program complies with FGDC
standards for vegetation classification, metadata, spatial data
transfer, and positional accuracy.

.

**Field Reconnaissance** -- Preliminary field visits by photo
interpreters and vegetation classification experts to gain an overview
of the vegetation of the project area and how it relates to the NVCS.
Communication between photo interpreters and vegetation classification
experts during this fieldwork is key to developing an accurate
classification system. Observation point data are collected during this
reconnaissance.

**Field Verification** -- Field visits by photo interpreters after photo
interpretation is complete to check for correctness of photo
interpretation. At this point changes may be made to the photo
interpretation. This occurs prior to accuracy assessment.

**Flight line**. -- Refers to a line or strip of aerial photography.
Usually designated on the film as 'flightline number -- photo number'.
Technical: A line connecting the principal points of sequential vertical
aerial photographs (Portions from ASP, 1984)

**Floristics** -- The kinds and number of plant species in particular
areas and their distribution (ESA, 1999).

**Formation** -- A level in the National Vegetation Classification
Standard hierarchy below subgroup which represents vegetation types that
share a definite physiognomy or structure within broadly defined
environmental factors, relative landscape positions, or hydrologic
regimes (Grossman et al. 1998). See table under USNVC.

**Geographic Information System** (GIS). -- An organized collection of
geographically (spatially)-referenced information. (Portions from ESRI,
1994)

**Georeference**. -- The process of converting a map or image into
real-world coordinates. A non-georeferenced map or image is said to be
in 'digitizer-inches' or 'scanner-inches', i.e., it has no real world
coordinates.

**Global Positioning System** (GPS) -- A system of satellites, ground
receiving stations and handheld receivers that allow accurate
measurement of feature coordinates on the face of the earth. GPS
receivers are used to measure the location of field plots,
reconnaissance points, and accuracy assessment points.

**Gradsect** -- Gradient directed transect sampling. This approach is
based on the distribution of patterns along environmental gradients. The
gradsect sampling design is intended to provide a description of the
full range of biotic variability (e.g., vegetation) in a region by
sampling along the full range of environmental variability. Transects
that contain the strongest environmental gradients in a region are
selected in order to optimize the amount of information gained in
proportion to the time and effort spent during the vegetation survey
(Grossman, Goodin, et al., 1999).

**Ground photograph**. -- An image recorded with the photographer
standing on the ground (as opposed to an aerial photograph).

**Ground truth**. -- The process of taking aerial photographs into the
field to verify the ground condition compared to how that condition
appears in the photograph.

**Group** -- The level in the National Vegetation Classification
Standard hierarchy below subclass based on leaf characteristics and
identified and named in conjunction with broadly defined macroclimatic
types to provide a structural-geographic orientation (Grossman et al.,
1998). See table under USNVC.

**Habitat** -- The combination of environmental or site conditions and
ecological processes influencing a plant community. (ESA, 1999).

**Habitat Type** -- (1) a collective term for all parts of the land
surface supporting, or capable of supporting, the same kind of climax
plant association (Daubenmire 1978); (2) an aggregation of land areas
having a narrow range of environmental variation and capable of
supporting a given plant association (Gabriel and Talbot 1984).

**Hectare**. -- A metric unit of measure equal to 10,000 m^2^ or
approximately 2.471 acres.

**Height** -- Height of the overstory of a vegetation community.. One of
the physiognomic modifiers classified in the USGS-NPS Vegetation Mapping
Program. Height in map units is classified as \< 0.5 meters, 0.5 - 2
meters, 2 - 5 meters, 5 - 15 meters, 15 - 35 meters, 35 - 50 meters,
\>50 meters. Compare with density and pattern

**Inventory and Monitoring (I&M) Program** -- A NPS program developed 1)
to collect baseline inventories of basic biological and geophysical
natural resources for all natural resource parks, 2) to set up long-term
monitoring programs will be developed to efficiently and effectively
monitor ecosystem status and trends over time at various spatial scales.
The USGS-NPS Vegetation Mapping Program collaborates closely with the
I&M Program.

**Integrated Taxonomic Information System** (ITIS) **--** A
comprehensive, standardized reference for the scientific names, and
synonyms and common names, for all the plants and animals and other
biological organisms of North America and the surrounding oceans
developed and maintained by an international partnership among agencies,
organizations, and taxonomic specialists. This database is accessible
over the Internet and is used by scientists, resource managers,
educators and students, museum curators, conservationists, and the
interested public. The PLANTS database is an important ITIS partner
providing plant taxonomic information to ITIS. See
<http://www.itis.usda.gov/>.

**Land Cover Classification** -- A classification of the cultural,
physical, and vegetation features that cover the earth, commonly used
with remote sensing technology. Vegetation classification is a subset of
land cover classification.

**Land Use Classification** (LUC) -- A classification of the earth's
surface that defines the use that people are making of the land,
commonly used with remote sensing technology, and commonly combined with
land cover classification. Natural vegetation areas may be classified as
"vacant" or "forest", or "grazing".

**Land Use/Land Cover Classification** (LU/LUC) -- A combination of a
land use classification and land cover classification where the land use
classification is used to classify areas that are under a definite land
use, such as agriculture, residential, or mining. The land cover
classification is used to classify lands that that do not have definite
land use, such as areas of bare rock, snow and ice, or open water. The
Anderson Classification System is a land cover and land use
classification.

**Look Up Table** (LUT) -- A computer file that relates the elements of
one classification to another in a crosswalk. The values of a map
classification are related to the associations of the NVCS in a park
project.

**Map Accuracy** -- A measure of the maximum errors permitted in
horizontal positions and elevations shown on maps. The National Map
Accuracy Standard of the USGS at 1:24,000 scale is the map accuracy
standard for the program. This standard is that 90% of well-defined
objects should appear within 40 feet (12.2 meters) of their true
location. See United States National Map Accuracy Standards.

**Map Attribute** -- Collectively the map class (or map unit) code, the
physiognomic modifier codes, and special modifiers if they are used: map
unit code is that portion of the map attribute code defining the map
unit (e.g. AB) the physiognomic modifier code -- portion of map
attribute code defining the vegetation community's structure (e.g.
-1A3). The map attribute code is thus AB-1A3.

**Map Class** -- The vegetation units that can be discerned on an aerial
photograph. Often associations in an alliance cannot be distinguished on
an aerial photograph because the differences are found in the
understory, so map classes must be developed. For example, at Devils
Tower National Monument there were five associations in the Ponderosa
Pine Woodland Alliance, but it was necessary to create two ponderosa
pine map classes because the associations could not be distinguished on
the photography. Map classes may be complexes or mosaics of associations
or map classes may also be the same as an association if that can be
discerned on the photograph. Also known as map unit.

**Map Scale** -- The relationship between a distance portrayed on a map
and the same distance on the Earth (Dana, 1999). A map scale can be
defined by a representative fraction (e.g., 1 unit on map / 12,000 units
on ground) or by a graphic scalebar.

**Map Unit --** See map class.

**Map Validation** -- The process of field checking and updating photo
interpretation. This step is completed prior to accuracy assessment.

**Metadata** -- Data about data. Metadata describes the content,
quality, condition, and other characteristics of data. Its purpose is to
help organize and maintain a organization\'s internal investment in
spatial data, provide information about an organization\'s data holdings
to data catalogues, clearinghouses, and brokerages, and provide
information to process and interpret data received through a transfer
from an external source (FGDC 1997). The FGDC sets standards for
metadata content and structure.

**Minimum Mapping Unit** (MMU) -- The smallest area that will be
consistently delineated during photo interpretation. The MMU for the
USGS-NPS Vegetation Mapping Program is 0.5 hectares.

**Mosaic** -- An intermixing of associations in an area that can be
distinguished on the aerial photography, but is too intricate to
delineate each association polygon. Compare with complex.

**National Biological Information Infrastructure** (NBII) -- A broad,
collaborative program to provide increased access to data and
information on the nation\'s biological resources. The NBII links
diverse, high-quality biological databases, information products, and
analytical tools maintained by NBII partners and other contributors in
government agencies, academic institutions, non-government
organizations, and private industry. Resource managers, scientists,
educators, and the general public use the NBII to answer a wide range of
questions related to the management, use, or conservation of this
nation\'s biological resources. The USGS-NPS Vegetation Mapping Program
is part of NBII.

**National Biological Service** (NBS) -- The agency that originated the
USGS-NPS Vegetation Mapping Program. Organized as the National
Biological Survey in 1993, its name was changed to National Biological
Service in 1995. It became the USGS Biological Resources Division in
1996.

**National Park Service** (NPS) -- A U.S. Department of Interior agency,
created in 1916, charged with preserving unimpaired the natural and
cultural resources and values of the national park system for the
enjoyment, education, and inspiration of this and future generations.
NPS manages the National Parks and the Inventory and Monitoring Program
and works closely with USGS to coordinate the USGS-NPS Vegetation
Mapping Program

**National Vegetation Classification Standard** (NVCS) -- The Federal
Geographic Data Committee's vegetation classification standard. It has
been adopted to the formation level (as of June 2001); adoption of the
floristic levels is pending. It is based on the Association for
Biodiversity Information's United States National Vegetation
Classification (USNVC) system. See table under USNVC for comparison and
crosswalk.

**Natural Heritage Programs** -- Natural Heritage Programs gather,
manage, and distribute information about the biological diversity found
within their jurisdiction. Most programs are part of government
agencies---such as natural resources or fish and wildlife
departments---although some are located within universities or
non-governmental organizations. The Association with Biodiversity
Information works closely in partnership with Natural Heritage Programs
to organize, store, and disseminate data collected by the Programs.
Natural Heritage Programs often collaborate on vegetation mapping
projects in their states.

**Natural Resources Conservation Service** (NRCS) -- (Formerly the Soil
Conservation Service, formerly the Bureau of Soils) The NRCS, U.S.
Department of Agriculture, producer to the Nation's Soil Surveys, is the
lead Federal agency for conservation on private land and is a partner in
conservation with many state, local and tribal organization.

**Natural Vegetation --** Plant life of an area that appears to be
unmodified by human activities. Most existing vegetation has been
subjected to some alteration by human activities, so a clear distinction
between natural and cultural vegetation may be difficult (Grossman et
al., 1998 ).

**NatureServe** -- A website from ABI that provides authoritative
conservation information in a searchable database for more than 50,000
plants, animals, and ecological communities in the U.S. and Canada.
Vegetation community data developed by the USGS-NPS Program is available
on NatureServe (URL is <http://www.natureserveexplorer.org/>).

**North American Datum** (NAD) -- The datum for map projections and
coordinates throughout North America (see also datum). Usually
associated with a version, such as 1927 or 1983. This Program uses the
1983 datum (NAD83), which is consistent with satellite location systems.
The 1983 datum uses the GRS 80 spheroid whereas the 1927 datum uses the
Clarke 1866 spheroid. (Portions from ESRI, 1994)

**Observation Point --** A field location point used to support map unit
and vegetation classification development. These points are collected
during reconnaissance and the mappers' subsequent fieldwork.

**Order** -- The 2^nd^ highest level in the NVCS hierarchy under
Division. The Orders within the Vegetated Division are generally defined
by dominant life form (tree, shrub, dwarf shrub, herbaceous, or
non-vascular). (FGDC, 1997). See table under USNVC.

**Ortho Image --** An aerial photograph that has had the distortions due
to camera lens, topographic relief, tilt of the aircraft, and other
factors common to aerial photography removed and has been registered to
locations on the earth. A digital ortho image can be placed in a GIS and
have other layers, such as vegetation, overlain on it. Aerial photo
interpretation can also be registered to an ortho image in the process
of registering and automating the data into a GIS. A DOQ is a digital
ortho image covering 3.75 minutes by 3.75 minutes of the earth's
surface.

**Pattern** -- Configuration of vegetation features or across a
landscape. One of the physiognomic modifiers classified in the USGS-NPS
Vegetation Mapping Program. Pattern in map units is classified as Evenly
Dispersed, Clumped/Bunched, Gradational/Transitional, Alternating.
Compare with density and height.

**Photo Interpretation** -- The art and science of identifying and
delineating objects on an aerial photograph. Photo interpreters in the
USGS-NPS Vegetation Mapping Program are knowledgeable about the
vegetation in their project area and highly skilled in identifying
vegetation map units accurately and consistently.

**Photo Interpretation Key** -- A description of the distinguishing
features that make up the signature of each map class. This description
may include written clues, as well as graphic examples of the
signatures.

**Photo-signature** -- Characteristics of an item on a photograph by
which the item may be identified.

**Physiognomic Modifiers** -- Modifiers used for mapping to describe the
physiognomic structure of the vegetation found within a mapped polygon
(coverage density, coverage pattern, and height.

**Physiognomy** -- The structure and life form of a plant community
(FGDC, 1997).

**Plant Community --** See community.

**PLANTS Database** -- A database maintained by the Natural Resource
Conservation Service that is a single source of standardized information
about plants. This database focuses on vascular plants, mosses,
liverworts, hornworts, and lichens of the U.S. and its territories. The
PLANTS Database includes names, checklists, automated tools,
identification information, species abstracts, distributional data, crop
information, plant symbols, plant growth data, plant materials
information, plant links, references, and other plant information. This
is the database that maintains current scientific names. The PLANTS
database provides the Integrated Taxonomic Information System (ITIS)
data for plants. The PLANTS database is the taxonomic authority for the
USGS-NPS Vegetation Mapping Program. For more information go to
<http://plants.usda.gov/>.

**Plot --** A formal field location of a certain size where the data
necessary to classify the vegetation communities is collected. The data
generated from the plot data collection is subsequently entered into a
database known as the PLOTS database. Plot size will vary depending on
the vegetation physiognomy being sampled. Synonymous with vegetation
plot. For more information see Grossman, et al., 1994 at
<http://biology.usgs.gov/npsveg/fieldmethods/index.html>.

**PLOTS database --** A database in Microsoft Access format that
contains the information collected from field plots with tables and
fields for all the necessary data. The PLOTS database table structure
and user' guide can be downloaded from
<http://biology.usgs.gov/npsveg/tools/plotsdatabase.html>.

**Positional Accuracy** -- The nearness of a point in a spatial database
to its actual location on the earth's surface. The program standard for
horizontal positional accuracy meets National Map Accuracy Standards at
the 1:24,000 scale. This means that each well-defined object in the
spatial database will be within 1/50 of an inch of its actual location
or 40 feet (12.2 meters).

**Potential Vegetation** -- the vegetation structure that would become
established if all successional sequences were completed without
interference under the present climatic and edaphic conditions (ESA,
1999). Contrast with existing vegetation.

**Precision Lightweight GPS Receiver** (PLGR) -- A small, handheld,
Global Positioning System (GPS) receiver featuring selective
availability/anti-spoofing (SA/A-S) and anti-jam capability.

**Producers\' accuracy** -- The probability that a reference sample (the
ground data) has been classified correctly, also known as error of
omission. This quantity is computed by dividing the number of samples
that have been classified correctly by the total number of reference
samples in that class (Story and Congalton 1986). Compare with user's
accuracy.

**Projection** -- A map or a geospatial database is a flat
representation of data located on a curved surface. A projection is a
device for producing all or part of a round body on a flat sheet. This
projection cannot be done without distortion, so the cartographer must
choose which characteristic (distance, direction, scale, area, or shape)
that is to be emphasized at the expense of the other characteristics
(Snyder, 1982). All spatial data in the program are represented in the
Universal Transverse Mercator (UTM) coordinate system that is based on
the transverse mercator projection applied between 84 degrees north and
80 degrees south latitude.

**Quadrangle** -- A USGS paper map. Typically, a 7.5-minute USGS map.
Informally known as quad.

**Quarter quadrangle** -- A map or image that includes ¼ the area of a
7.5-minute quadrangle and is organized in quadrants of the original
quadrangle as follows: Northeast, Northwest, Southeast, and Southwest.
USGS DOQ's cover ¼ of a 7.5-minute quadrangle. . Informally known as
quarter quad.

**Rectify --** Remove distortions common to aerial photographs in the
process of automating the photo-interpreted information into a digital
database. Distortions on aerial photographs are due to topographic
relief on the ground, radial distortion in the geometry of the aerial
photography, tip and tilt of the plane, and differences in elevation of
the airplane from its nominal scale. This process may be separate or
included in the registration process depending on the technology used.
See transfer.

**Register --** The process of correlating objects on an aerial
photograph with locations on the surface of the Earth using a defined
coordinate system. This is necessary to be able to place the vegetation
community data in a GIS with other appropriate data such as
transportation, topography, soils, etc. This process may be separate or
included in the rectification process depending on the technology used.
See transfer.

**Scale** -- The relationship between a distance portrayed on a map and
the same distance on the Earth (Dana, 1999). A map scale can be defined
by a representative fraction (e.g., 1 unit on map / 12,000 units on
ground) or by a graphic scale bar.

**Spatial Data Transfer Standard** (SDTS) -- A comprehensive transfer
standard for Earth-referenced data endorsed by the Federal Geographic
Data Committee. Spatial data in SDTS format consists of a group of files
each with specific content and format.

**Special Modifiers --** Modifiers used as part of a map attribute to
describe special features that are not part of the USNVC. For example, a
park may be interested in eagle nests, beaver dams, prairie dog towns,
and forest blow-down. See map attributes, map codes, and physiognomic
modifiers.

**Signature** -- The unique combination of color, texture, pattern,
height, physiognomy, and position in the landscape used by an photo
interpreters to identify map classes on an aerial photograph.

**Stratum** -- A horizontal layer of vegetation. A stratum may be
defined by the life form of the vegetation (tree, shrub, herbaceous), or
its actual height.

**Structure (Vegetation)** -- The spatial distribution pattern of life
forms in a plant community, especially with regard to their height,
abundance, or coverage within the individual layers (ESA, 1999).
Synonymous with physiognomy.

**Subclass** -- The level in the National Vegetation Classification
Standard hierarchy under class based on growth form characteristics
(Grossman et al. 1998). See hierarchy under USNVS.

**Subgroup** -- The level in the National Vegetation Classification
Standard hierarchy below group which divides each group into either a
\"natural/semi-natural\" or \"cultural\" (planted/cultivated) subgroup
(Grossman et al. 1998). See hierarchy under USNVS.

**Thematic Accuracy** -- The correctness of the map classes in relation
to the vegetation on the ground. This is determined through the accuracy
assessment procedures and the program standard is 80% accurate for each
map class at the 90% confidence interval. See accuracy assessment,
producer's accuracy and user's accuracy.

**The Nature Conservancy** (TNC) -- A nonprofit conservation
organization founded in 1951.  Working with communities, businesses and
people TNC protects millions of acres of valuable lands and waters
worldwide. TNC was the original caretaker of the USNVC, but those
responsibilities have been spun off to the Association for Biodiversity
Information. TNC no longer has an active role with the USGS-NPS
Vegetation Mapping Program.

**Topographic Quadrangles** -- USGS paper maps showing the topography of
an area along with roads, railroads, water bodies, building, urban
developments, and wetlands. These come in a variety of scales, but
commonly refer to 1:24,000 scale 7.5-minute quads. Informally referred
to as topo quads.

**Transfer** -- The process of moving photo interpreted data from an
aerial photo overlay to an ortho image to register and rectify the data.
This process varies depending on the type of technology used.

**Transform(ation)**. -- The process of converting coordinates (map or
image) from one coordinate system to another. This involves scaling,
rotation, translation, and warping (images) (ESRI, 1994).

**Transition Zone --** An area where the vegetation composition and
structure is intermediate between two associations. The transition zone
may be small as the associations abruptly change due to a large shift in
the landscape, such as a cliff, or it may be large as the physical
environment changes gradually. Transition zones often are challenges to
properly classify and/or map vegetation.

**Type --** A generic term that can reference any vegetation level in
the USNVC, whether it is association, alliance, formation, etc, and even
a combination of levels, or no reference to a known "type" within the
classification. It a vague but useful term. It is correctly used when
the focus is not on the vegetation "type," but rather when used loosely
to explain some other point that one is trying to get across (e.g., "We
do not have a good grasp of how vegetation types at Acadia link to the
map units used for mapping."). "Types" refers to all levels of the
classification, not specific association level. Plus the focus is on
"not have a good grasp," not the vegetation type or map unit. Also known
as vegetation type.

**Upper Midwest Environmental Sciences Center** (UMESC) -- A USGS
Science Center concerned with large river issues and medicinal drugs for
public aquaculture. UMESC has established a significant geospatial
technologies capability and is managing several park projects for the
USGS-NPS Vegetation Mapping Program.

**United States Geological Survey** (USGS) -- Established in 1879, the
USGS is the natural science agency for the Department of the Interior.
The USGS is the one of the host agencies, along with the National Park
Service, for the USGS-NPS Vegetation Mapping Program.

**United States National Map Accuracy Standards** (NMAS) -- USGS
accuracy standards for published maps, including horizontal and vertical
accuracy, accuracy testing method, accuracy labeling on published maps,
labeling when a map is an enlargement of another map, and basic
information for map construction as to latitude and longitude
boundaries. The table below shows the standard for some common map
scales. To meet NMAS maps must have less than 10 percent of the points
tested (well-defined points) exceed the standard. Note that the
conversion of paper maps into digital data usually creates additional
error.

Horizontal Accuracy Examples

Scale Engineering National Map

Scale Accuracy Standard

\-\-\-\-\-\-\-\-\-\-- \-\-\-\-\-\-\-\-\-\-\-\-\-\--
\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

1:1,200 1\"=100\' +/- 3.33 feet

1:2,400 1\"=200\' +/- 6.67 feet

1:4,800 1\"=400\' +/- 13.33 feet

1:9,600 1\"=800\' +/- 26.67 feet

1:10,000 +/- 27.78 feet

1:12,000 1\"=1000\' +/- 33.33 feet

1:24,000 1\"=2000\' +/- 40.00 feet

1:63,360 1\"=one mile +/- 105.60 feet

1:100,000 +/- 166.67 feet

**United States National Vegetation Classification** (USNVC) -- The
Association for Biodiversity's vegetation classification system. It is
the basis for the FGDC National Vegetation Classification Standard. See
table below for comparison

  -------------- ------------- ----------------- -----------------------------
                 **ABI USNVC** **FGDC NVCS**     **Example**

  Physiognomic   System                          Terrestrial
  Levels                                         

                               Division          Vegetated

                               Order             Tree

                 Class         Class             Woodland

                 Subclass      Subclass          Evergreen Woodland

                 Group         Group             Temperate or subpolar
                                                 needle-leaved evergreen
                                                 woodland

                 Subgroup      Subgroup          Natural or semi-natural
                                                 vegetation

                 Formation     Formation         Rounded-crowned temperate or
                                                 subpolar needle-leaved
                                                 evergreen woodland

  Floristic      Alliance      Alliance (not     Juniperus scopularum Woodland
  Levels                       finally adopted)  Alliance

                 Association   Association (not  Juniperus
                               finally adopted)  scopularum/*Oryzopsis
                                                 micrantha* Woodland
  -------------- ------------- ----------------- -----------------------------

**User's accuracy** -- The probability that a sample from the mapped
data actually represents that category on the ground, also known as
error of commission. This quantity is computed by dividing the number of
correctly classified samples by the total number of samples that were
classified as belonging to that category (Story and Congalton 1986).
Compare with producer's accuracy.

**Universal Transfer Mercator** (UTM) --A map coordinate system (not a
map projection) that is defined by the Transverse Mercator projection
which has a set of zones defined by a central meridian as shown in the
figure below for the United States (Portions from ESRI, 1994). All
spatial data products developed by the program (vegetation spatial data,
plot and accuracy assessment plot data locations are in this coordinate
system.

![](media/image1.png){width="3.71875in" height="2.46875in"}

**Vector Data**. -- Spatial (usually digital) data that consists of
using coordinate pairs (x, y) to represent locations on the earth.
Features can take the form of single points, lines, arcs or closed lines
(polygons).

**Vegetation** -- The collective plant cover over an area (FGDC, 1997).

**Vegetation Characterization --** The detailed portrayal of a
vegetation association using diagnostic and dominant species, structure,
and ecological processes. The program has a formal structure for
association description based on the ABI model. Also known as vegetation
description. An example of an association characterization can be found
at <http://biology.usgs.gov/npsveg/agfo/mapclass/scbc.pdf>.

**Vegetation Classification --** The process of categorizing vegetation
into repeatable and consistent elements. Also a document the lists and
organizes the vegetation communities in an area. An example of a
vegetation classification can be found at
<http://biology.usgs.gov/npsveg/agfo/report.pdf#classification>.

**Vegetation Community --** See community.

**Vegetation Description** -- See vegetation characterization.

**Vegetation Field Key --** See dichotomous field key

**Vegetation Key --** See dichotomous field key

**Vegetation Mapping** -- The process of identifying, labeling, and
placing in real world coordinates vegetation communities.

**Vegetation Plot --** See plot.

**Vegetation Structure** -- See structure (vegetation).

**Vegetation Type** -- See type.

**Vertical Aerial Photography** -- See Aerial Photography.

**Wetland --** A location on the landscape that is characterized by
either hydric soils or hydrophytic plants or both. A wetland may be
vegetated or non-vegetated. The vegetation description for each
association includes it wetland status.

**Literature Cited:**

American Society of Photogrammetry. 1984. Multilingual Dictionary of
Remote Sensing and Photogrammetry. Rabchevsky, G.A. (Editor). Falls
Church, VA. 343pp.

Anderson, J.R., E.E. Hardy, and J.T. Roach 1976. Land Use and Land Cover
Classification System for Use with Remote Sensing Data. Geological
Survey Professional Paper 964. A revision of the land use classification
system as presented in US. Geological Circular 671. U. S. Government
Printing Office, Washington, D.C.

Anonymous. Establishing standards for using existing vegetation data.
1996. Prepared for the USGS-NPS Vegetation Mapping Program by The Nature
Conservancy, Arlington VA, and Environmental Science Research Institute,
Redlands, CA.

Cowardin, L. W., V. Carter, F.C. Golet, and E. T. LaRoe. 1979.
Classification of Wetlands and Deepwater Habitats of the United States.
Biological Service Program, U.S. Fish and Wildlife Service, FWS/OBS
79/31. Office of Biological Services, Fish and Wildlife Service, U.S.
Department of Interior, Washington, D.C., USA.

Dana, P.H. Map Projection Overview. 1999.
<http://www.colorado.edu/geography/gcraft/notes/mapproj/mapproj_f.html>.

Daubenmire, R.F. 1978. Plant Geography, with Special Reference to North
America. New York, New York.

Environmental Systems Research Institute, Inc. 1994. *Understanding GIS:
The Arc/Info Method*. Redlands, CA.

Federal Geographic Data Committee. Vegetation Classification Standard.
1997.
<http://www.fgdc.gov/standards/projects/FGDC-standards-projects/vegetation/NVCS_V2_FINAL_2008-02.pdf/>.

Gabriel, H.W. and S.S. Talbot. 1984. Glossary of Landscape and
Vegetation Ecology for Alaska. Alaska Technical Report 10. Bureau of
Land Management, U.S. Department of the Interior, Washington, D.C.

Grossman, D.H., D. Faber-Langendoen, A.S. Weakley, M. Anderson, P.
Bourgeron, R. Crawford, K. Goodin, S. Landal, K. Metzler, K. Pattterson,
M. Pyne, M. Reid, and L. Sneddon. 1998. International classification of
ecological communities: terrestrial vegetation of the United States.
Volume I. The Nature Conservancy, Arlington, VA.

Grossman, D.H., K.L. Goodin, X. Li, D. Faber-Langendoen, and M.
Anderson. Developing and documenting a National Vegetation
Classification Standard. 1994. Prepared for the USGS-NPS Vegetation
Mapping Program by The Nature Conservancy, Arlington VA, and
Environmental Science Research Institute, Redlands, CA.

Grossman, D.H., K.L. Goodin, X. Li, D. Faber-Langendoen, M. Anderson,
and R. Vaughan, Establishing standards for field methods and mapping
procedures. 1994. Prepared for the USGS-NPS Vegetation Mapping Program
by The Nature Conservancy, Arlington VA, and Environmental Science
Research Institute, Redlands, CA.

Snyder, John P. 1982. Map Projections Used by the U.S. Geological
Survey. 2^nd^ Edition. United States Government Printing Office,
Washington, D.C.

Stadelmann, M., A. Curtis, R. Vaughan, and M. Goodchild. Producing
rigorous and consistent accuracy assessment procedures. 1994. Prepared
for the USGS-NPS Vegetation Mapping Program by The Nature Conservancy,
Arlington VA, and Environmental Science Research Institute, Redlands,
CA.

Story, M., and R. G. Congalton. 1986. Accuracy assessment: a user\'s
perspective. *Photogrammetric Engineering and Remote Sensing*, 52 (3):
397-399.