E. The Determination of Coordinates for Inclusion on the HAZSITE Database

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1. More detailed information regarding the application of the HAZSITE Database can be obtained by reviewing NJDEP's Electronic Data Interchange (EDI) manual. Discussed below are strategies for determining the coordinates required for inclusion in the HAZSITE Database.
2. Establishment of the coordinate framework for reporting site specific sampling locations. Concern has been expressed regarding the requirement to survey each sampling point during each field sampling event. Specifically, there is concern regarding the cost of hiring a licensed surveyor or the development and/or implementation of GPS capability every time a sampling event occurs at a contaminated site. Several options for reducing the expenses for determining these coordinates that are acceptable to the DEP are presented below.
   
   
1. Establishment of control point coordinates
   
   
1. Standard Surveying Techniques
   
   Using traditional survey equipment and techniques during initial sampling activities, it will be necessary establish one(1) surveyed control point for the site and for reference in future sampling events. The control point should be located as close to the center of the property and areas of investigation as feasible. To facilitate registering the point on the site plan, it is recommended that the control point be located on or adjacent to existing surface construction features already reflected on existing architectural or CAD drawings. The control point must represent, within 1.5 meters, the actual location on the facility property.
2. Global Positioning System (GPS)Another method for establishing a control point for grid system development is GPS. As with traditional survey techniques, it is necessary to establish one control point for the site and for reference in future sampling events. The control point should be located as close to the center of the property and areas of investigation as feasible. To facilitate registering the point on the site plan, it is recommended that the control point be located on or adjacent to existing surface construction features already reflected on existing architectural or CAD drawings. The control point must represent, within 3 meters, the actual location on the facility property.The GPS receiver employed should be designed for GIS data collection or precise surveying. Critical receiver collection parameters must be set by the receiver operator to ensure the collected control point positions are of acceptable quality and meet DEP requirements. These parameters include position (or fix) collection mode, PDOP mask, satellite elevation mask, signal to noise ratio (SNR) mask, and number of sample fixes collected per point.(a) The position collection mode should be 3D (4 or more GPS satellites used to determine position) or over-determined 3D (5 or more satellites). And the GPS unit should be a code based, 6 channel receiver at a minimum. (b) Satellite geometry conditions should be such that PDOP is less than or equal to 6 during GPS collection. The receiver's PDOP mask should be set to 6. (c) The receiver's elevation mask should be set to 15 degrees.(d) The receiver's signal to noise ratio mask should be set to six (6).(e) The minimum number of sample fixes required will depend on the quality of the receiver employed. Regardless of receiver used, a minimum number of fixes must be collected so that when differentially corrected (either post processed or in real time), the final averaged position is accurate to within 3 meters 2drms (with a 95% level of confidence). (f) Additional, more detailed information regarding GPS use and techniques is in section 7.0 GLOBAL POSITIONING SYSTEM of "Mapping and Digital Data Standards."
   
   
2. Establishment of a facility grid coordinate system
   
   The coordinates established using survey or GPS techniques become the control point, and are included on the facility map to establish a baseline to determine coordinates for past and future sampling activities.Upon generation of New Jersey State Plane coordinates for the control point, it is necessary to register (locate) that point on the facility map. Note that registering of the control point is aided by being able to identify the point on the facility map where the survey or GPS sighting was taken. Accordingly, it is helpful to capture the point in the field as near as possible to an object identifiable both on the facility plan as well as on the ground. For example, one way the create a grid could include use of a hard copy architectural plan of the facility or CAD drawing. Establish a 2 dimensional, 1 foot square x-y grid system using the control point coordinates as a basis for determining additional grid based coordinate points. When preparing the grid, precisely identify true north on the map to ensure that future coordinates developed using this method are accurate. Grid dimensions must be established in NAD83 and in New Jersey State Plane feet, since it very difficult to establish a grid system using latitude and longitude coordinates. The Department's primary concern when developing coordinates for the HAZSITES Database is that spatial distribution of the coordinates is consistent. Note that it is not necessary to generate a 1'x 1' grid over the entire site plan, but only around those points and areas where the sampling activities are occurring.Once a grid with x and y coordinates has been established, the coordinate information correlating to the locations of sampling points and well placement can be used to complete the HAZSITES Database requirement for position information.
3. Locating a control point using orthophotography
   
   Another method for determining point coordinates involves the use of aerial orthophotography. Statewide 1995 digital imagery will be available on a county by county basis in the Universal Transverse Mercator (UTM), coordinate system, in NAD83 at a cost of approximately $150.00 to $300.00 per county. The product available will be 1 meter, resolution, JPEG, color infrared digital orthophoto quarterquads. The imagery is expected to be available for sale from the USGS, Earth Science Information Center at 1-800-USA-MAPS in the fall of 1997. This imagery, when available, can be used to develop coordinates as the base map for identification of sampling points. Built into the imagery is the UTM coordinate system that will allow for the establishment of facility field coordinates. Since the orthophoto coordinates are in UTM the respondent must convert the point to NAD83 and New Jersey State Plane feet before submission of the digital record to the DEP in the HAZSITE Database. Additional guidance regarding suggested methodologies for this conversion will be provided in subsequent editions of this guidance.

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Sections

• Table of Contents, Alternate Formats, and Contact Information
• Introduction
• Mapping and Digital Data Standards (MDDS) in Brief
• Specific spatial mapping and GIS information issues in NJAC 7:26 E and SRP operations that this guidance is intended to clarify, including:
  
  
  • Guidance for Map Submissions
  • Associated Information Files
  • Metadata Requirements for Digital Map Submissions
  • Using the NJDEP's GIS Resources as a Source of Information
  • The Determination of Coordinates for Inclusion on the HAZSITE Database
• Listing of NJDEP GIS and Site Remediation Information Resources
• Modifications to this Guidance