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Frequently Asked Questions about: GIS Help Desk: 609-777-0672

  1. What is GIS?
  2. What is Spatial Data?
  3. How is NJDEP using GIS to accomplish its mission?
  4. Where can I get information about NJDEP GIS standards?
  5. What GIS data has NJDEP made available?
  6. What do I need to use NJDEP GIS data?
  7. Can I redistribute NJDEP data?
  8. Can NJDEP produce a map for me, or furnish customized data retrievals from the NJDEP GIS database for my study?
  9. Can anyone make a map online using NJDEP data?
  10. Can I get training for NJ-GeoWeb?
  11. How do I obtain NJ State Plane coordinates for my DEP Permit Application Form?
  12. Where can I find historical aerial photography, base maps, etc.?
  13. What are map projections and coordinate systems and why are they important?
  14. Where can I obtain a coordinate conversion utility?
  15. Why am I having trouble launching or using the NJ-GeoWeb application?



  1. What is GIS?

    The term Geographic Information System (GIS) is used generically for any computer-based technique for the manipulation of geographic data. GIS is a broad field of endeavor, and incorporates the related fields of remote sensing and photogrammetry, as well as Global Positioning Systems (GPS). GIS includes not only hardware and software, but also the special devices used to manipulate geographic information to conduct spatial analysis and to create map products, together with communications systems needed to link various elements.

    For more information, check out http://www.esri.com/what-is-gis

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  3. What is Spatial Data?

    GIS data is often referred to as "spatial data" or "digital geospatial data." The term "geospatial" is derived from "geo" relating to the Earth, and "spatial" relating to location in space. Two broad categories of spatial data are known as "vector" and "raster". Beyond these main categories, other GIS-related data types include tabular data (database tables) and image data. All of these are discussed below.

    Vector data layers are comprised of points, connecting lines and polygons are recorded digitally using X-Y coordinates. Such images are fully scalable meaning they can be enlarged and reduced in size for display without sacrificing detail. Most map layers in GIS are expressed as vector images in order to conserve digital storage space, accelerate retrieval and minimize work involving analytical processing.

    Raster data layers are comprised of picture elements (pixels) that may be assigned a color value and intensity. An example of such images is a television picture. Raster images lose resolution (detail) as they are enlarged or reduced in size. These images usually occupy more storage space than vector images of the same area and require compression and expansion in use to conserve file space. Raster images usually result from the scanning process and in GIS are typically used for digitizing aerial photographs and background maps.

    Tabular data, often referred to as attribute data, because it is information that describes the attributes of features in a data layer, is stored in database tables. Rather than describing location, tabular data provides the descriptive information about the features in a layer.

    Image data or Digital Imagery is stored as raster data in a GIS and often provides an image as a backdrop to a vector data layer. Examples of image data include digital aerial photography, satellite imagery, scanned maps and photographs. Another term for image data commonly used is digital raster graphics (DRGs). USGS quadrangle topographic maps are often called USGS DRGs. Additional information on image data can be found in the Digital Imagery FAQs.

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  5. How is NJDEP using GIS to accomplish its mission?

    The use of GIS technology is integral to making better environmental decisions in programs ranging from water resource management to hazardous site clean up to wildlife habitat protection to emergency response. To see some examples of how the Bureau of GIS has facilitated GIS, review the web applications. Read more about us.

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  7. Where can I get information about NJDEP GIS standards?

    The NJDEP has developed GIS standards to assist users of the Department's data. The Mapping and Digital Standards document can be found on the GIS Standards page.

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  9. What GIS data has NJDEP made available?

    Most of NJDEP's GIS data is available for download in a variety of formats. Metadata (data documentation) for each layer is available as well.

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  11. What do I need to use NJDEP GIS data?

    The staff at the NJDEP commonly use:

    The ArcGIS suite of software produced by ESRI, Inc. and NJ-GeoWeb. Esri's ArcExplorer products and NJ-GeoWeb are free tools for Department staff and the public.

    NJDEP's NJ-GeoWeb is rich with environmental data. It features many of NJDEP's most requested data layers that can be viewed and queried in an internet browser.

    Explorer products allow users to perform basic GIS tasks such as: panning and zooming data layers; displaying data using classifications, symbols, and labels; and identifying and querying geographic and attribute data.

    Some NJDEP data sets are also available through subject specific applications on the NJDEP web pages.

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  13. Can I redistribute NJDEP data?

    The NJDEP requires that permission be obtained prior to redistributing the Department's data, and that the NJDEP Data Distribution policy be adhered to. For details, review the NJDEP Mapping and Digital Data Standards document, section VII NJDEP Data Distribution and Constraints.

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  15. Can NJDEP produce a map for me, or furnish customized data retrievals from the NJDEP GIS database for my study?

    While NJDEP cannot fulfill individual maps requests, we can provide quality data and interactive mapping applications that may enable you to produce the information you are looking for.

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  17. Can anyone make a map online using NJDEP data?

    Yes, by using NJ-GeoWeb, NJDEP's online interactive mapping application, anyone can use NJDEP GIS data without the need for downloading specialized software or data layers. NJ-GeoWeb runs in a browser and can be used to prepare maps you can print on your local printer. Online help, tutorials and training are available so that even those who are new to GIS should be able to use the NJ-GeoWeb application.

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  19. Can I get training for NJ-GeoWeb?

    Yes. For NJ-GeoWeb training dates check the training page.

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  21. How do I obtain NJ State Plane coordinates for my DEP Permit Application Form?

    This information can be obtained by using the NJ-GeoWeb interactive mapping application which displays NJ State Plane map coordinates at the lower right-hand corner of the map window:

    In this example, Easting (X): 420,360.02, Northing (Y): 505,440.52 denotes NJ State Plane Coordinates in feet. The first number is the X-coordinate (the easting) and the second number is the Y-coordinate (the northing). In order to be confident in the accuracy of the coordinates at the mouse cursor, you should zoom-in close enough that the location can be easily identified using the aerial photography and other base map layers.

    If you prefer, you can also call the GIS Help Desk at 609-777-0672 to obtain this information.

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  23. Where can I find historical aerial photography, base maps, etc.?

    NJ-GeoWeb includes some historical aerial photography. Non-digital historical aerial photography can be viewed at the NJDEP Tidelands Management Program aerial photo library. Appointments can be made by calling 609-292-2573. For information on New Jersey base maps, view the NJDEP Mapping and Digital Data Standards document and/or visit the NJDEP Maps & Publications web site.

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  25. What are map projections and coordinate systems and why are they important?

    All geographic data layers store locations in a map projection or coordinate system. Map projections and coordinate systems are important because in order for data layers to overlay correctly, they must be stored in the same system. Examples of coordinate systems include Latitude and Longitude, Universal Transverse Mercator (UTM), and NJ State Plane. These systems relate to the way locations on the Earth are stored in a data layer, and the need to make adjustments when translating locations from a sphere-shaped Earth to a flat map.

    The standard coordinate system used by NJDEP is the New Jersey State Plane Coordinate System, NAD83. Units of measure are in feet. All data layers available for download are in the New Jersey State Plane Coordinates (NJSPC).

    Additional information on map projections and coordinate systems is available at the USGS Map Projections web site.

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  27. Where can I obtain a coordinate conversion utility?

    The New Jersey Division of Water Supply and Geoscience provides a coordinate conversion utility for converting coordinates to/from Latitude/Longitude and NJ State Plane feet.

    The US Army Corps of Engineers' Corpscon utility also allows coordinate conversions but has more input and output options and will handle datum conversions as well. Other geodetic software utilities are available to download for free at the web site of the National Geodetic Survey (NGS).

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  29. Why am I having trouble launching or using the NJ-GeoWeb application?

    There is help available for NJ-GeoWeb on the application splash page.

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