Governor Phil Murphy • Lt.Governor Sheila Oliver
NJ Home
| Services A to Z | Departments/Agencies | FAQs 

State of New Jersey Department of Environmental Protection

State of New Jersey Department of Environmental Protection
Return to Division of Science, Research and Environmental Health Home


Return to NJ Digital Land Dataset - Home

What is the title of the data set?

Land Cover for New Jersey –

Mid Atlantic Gap Analysis Project

hat does the data set describe?

Land cover polygons of New Jersey

What geographic area does the data set cover?

Statewide coverage of New Jersey

What is the date that the data describes?

Data contains land cover description for vegetation as habitat.

How does the data set represent geographic features?

Features are represented by vector-based polygons (i.e. map features are digitally traced in a “connect the dots” manner)

How are geographic features stored in the data set?

Data is stored in ESRI shapefile format

What coordinate system is used to represent geographic features?

New Jersey State Plane North American Datum 1983

How does the data set describe geographic features?

Polygons delineate over 62 different land cover categories for land features focusing particularly on vegetation types.

What are the types of features present?

Numerous categories of forest or vegetative type are delineated by the dataset whereas non-vegetative habitat land cover types including urban and agricultural are delineated with no further detail than the general label.

Who produced the data set?

The data was produced for the Maryland Department of Natural Resources, Wildlife and Heritage Division.

To whom should users address questions about the data?

Maryland Department of Natural Resources, Wildlife and Heritage Division;

Why was the data set created?

The data was created to provide information on the geographic distribution of land cover (primarily vegetation types) for the purpose of mapping vertebrate species habitat associations.

What is the recommend use for the data?

Along with species habitat mapping, this dataset may be used for a variety of coarse (regional) scale landscape analysis/management purposes pertaining to land cover.

What are aspects of concerned for a non-specialist to interpret the data?

The final report of the Mid Atlantic Gap Analysis Project will provide more context for interpreting the mapping data set.

How was the data set created?

Satellite classification of Landsat TM imagery enhanced with a variety of ancillary data sources including aerial videography.

Were the source data compiled at a particular scale?

Imagery was 30 m pixels, compiled originally to 3 X 3 pixel minimum mapping units, later compiled to 5 X 5 pixel mapping units.

How reliable are the data; what problems remain in the data set?

All data have inherent limitations.  This dataset was compiled to a high level of accuracy.  A full description of the data accuracy and limitations is provided in the metadata available at: 

What can you say about the accuracy of the observations?

Minimum map unit was 2 hectares.  Horizontal accuracy should be within 30 meters, however slight shift errors attributable to resampling of ancillary data layers could result in additional random offset.

  Attribute error was calculated at 31.3% (absolute) and 67.6% fuzzy accuracy.

How can someone get a copy of the data set?

Visit for information on availability.

Are there legal restrictions on access or use of the data?

Restrictions include: 1) using the data for measurements finer than the intended scale; 2) establishing the exact boundaries for regulation or acquisition; 3) establishing definite presence or absence of any element; 4)determining abundance, health, or condition of any element; 5) establishing a measure of accuracy of any other data by comparison with this dataset; 6) combining these data with any other data finer than the intended scale for analysis; 7) use of this data to map small areas typically requiring mapping at resolution at 1:24000 scale and using aerial photographs and ground surveys; and 8) altering the data in any way and redistributing as a GAP product.

Who distributes the data?

US Geological Survey Gap Analysis Program;

How can people download or order the data?

Visit for information on availability.

In what formats are the data available?

Data is available in ESRI Inc. shapefile format.

What hardware or software do people need in order to use the data set?

Data can be utilized by a number of GIS applications including Arcview 3.2, ArcINFO, ArcGIS and Arc Explorer which is a free GIS viewer available at

What are some suggested uses of the Data for New Jersey’s various communities of user?

The data can be utilized for: 1) statewide biodiversity planning; 2) regional and large area resource planning; 3) course-filter evaluation of potential impacts or benefits of major projects/initiatives on biodiversity, such as utility or transportation corridors, wilderness proposals, open space or recreation proposals; 4) environmental impact assessment for large projects such as military activities; 5) education at all levels for both students and citizens.

Potential applications:

(environmental management)

Inventory and location of the state’s natural vegetation communities.

Potential applications:

(regional planning)

Useful for regional natural resource inventories, watershed characterizations, identification of lands for preservation.

Potential applications:

(local planning)

Minimum polygon size places constraints on its utility at the local level.  If used in conjunction with NJDEP LULC95 or CRSSA LC95 it can provide supplementary vegetation community classification information.

Potential applications:

(habitat analysis)

Identify unique or rare natural communities that may represent significant habitats for flora and  fauna.

Potential applications:

(open space preservation)

Assist in the identification of lands that contain significant assemblages of natural communities.

Division of Science, Research and Environmental Health
Dr. Gary A. Buchanan, Director
Mailing Address:
Mail code 428-01, P.O. Box 420
Trenton, NJ 0862

Phone: (609) 984-6070
Fax: (609) 292-7340