**New Jersey Geological Survey
DGS03-1, Coordinate Conversion Utility
Version 1.0.4** (March 16, 2006)

Programed by: William Mennel (Retd.)

James Boyle email: James.Boyle@dep.nj.gov

New Jersey Geological Survey

http://www.state.nj.us/dep/njgs

**This program is provided and may be utilizied without charge.
No warranty, expressed or implied, is provided as to the serviceability
or usefulness of this program.**

**USERS GUIDE**

ContentsLimitations

Run-time Error

Coordinate Entry Conventions

Atlas Sheet Coordinate System

State Plane Coordinate System (SPCS)

NAD27 <=> NAD83

References

This program was designed to convert New Jersey State plane coordinates (NAD83) to latitude and longitude (NAD27 and NAD83). The geographic area for which this conversion will work is bounded on the east by longitude 73° 37' 30" and on the west by 75° 37" 30". It is bounded on the south by latitude 38° 45' 00" and on the north by 41° 22' 30". This conversion is for the horizontal coordinates and does not address the vertical coordinate.

**State Plane Coordinates (Easting & Northing)**

State plane coordinates are NAD83 datum points. The easting and northing are to be entered in US survey feet with up to three decimal places.

**Geographic Coordinates (Latitude & Longitude)**

Latitude and longitude can be in either NAD27 or NAD83. They can be entered as either decimal degrees or as degrees, minutes, and decimal seconds. If entered as decimal degrees at least five decimal places should be entered. If entered as degrees, minutes, and decimal seconds the value needs to be entered without spaces between the units and with leading zeros in the minutes and seconds for values less than ten. Up to three decimal places may be entered. The longitude is always entered as a positive value without a leading zero.

**Atlas Sheet Coordinates**

The Atlas Sheet coordinate is a seven-digit number. All seven-digits must be entered. Entry is controlled by the use of a mask. The second pair of digits, which represent a specific block on the atlas sheet, must be entered with a leading zero for blocks one through five. These coordinates are based on NAD27 so the latitude and longitude generated are NAD27.

**Batch Conversion **

The batch allows for the input of state plane, latitude/longitude, or atlas
sheet coordinates for conversion. The file to be converted must be an ASCII
delimited text file. The format of the file for converting state plane or
latitude/longitude is **Id, Y-coordinate (Northing or
Latitude), X-coordinate (Easting or
Longitude)**.

Example: 3164855, 368154.62, 312006.32

The format of the file for converting atlas sheet coordinates (ASC)
is **Id, ASC**. The
ASC coordinate must have a seperators between the Sheet Number, Block Number
and Rectangle Number.

Example: 3164855, 31:02:229

The Block Numbers must use leading zeros for blocks 1 through 5. The Rectangle Number can not contain zeros for any of the values. If the complete three digit Rectangle Number is unknown the trailing zeros can be replace with the value 5 to obtain the location of the center of the next larger rectangle. This however in creases the size of the area represented by the ACS.

Select the Input coordinates, datum and units in the boxes for your data file and then press the "Run batch" button. Navigate to the file folder of your file. Select it and press the "Open" button.

The output file created is an ASCII delimited text file called "convert.dat" and is located in the same folder as the input file. The format for this file is Id, Northing, Easting, Latitude (NAD83), Longitude (NAD83), Latitude (NAD27), Longitude (NAD27), Atlas Sheet Coordinate, USGS Quadrangle Name. Also created is a file called "problem.dat" which lists any points which were not converted.

The New Jersey Geological Survey (NJGS) developed a location system, known as the New Jersey Atlas Sheet Coordinate System (ASCS) (Kümmel, 1912, p.13 and Kümmel, 1913, p 13). The ASCS was designed to be easier to use and understand than the latitude and longitude system.

The Atlas Sheets, on a scale of 1:63,360, or 1 inch per mile, are the basis of the system. The sheets are numbered from 21 to 37, and are divided into rectangles, each covering, 2 minutes of latitude and longitude. Each Atlas Sheet spans 28 degrees of latitude and 26 degrees of longitude, making 13 rectangles from east to west and 14 from north to south.

Every third line of latitude and longitude delineates a 6-minute block, for 16 complete blocks, each containing 9 smaller 2-minute rectangles. Beginning in the upper left-hand corner, these blocks are numbered across the sheet 01 to 04. The blocks of the second row are numbered 11 to 14, those of the third row 21 to 24, of the fourth row 31 to 34.

In addition to the 16 complete 6-minute blocks there is, along the right-hand side of the sheet, a single row of 2-minute rectangles and along the bottom, a double row of 2-minute rectangles. The incomplete blocks of the fifth row at the bottom, 41 to 44, contain 6 of the 2-minute rectangles. The blocks along the right (vertical) side (05, 15, 25, and 35) each contain 3 of the 2-minute rectangles. Block 45 in the lower right corner contains only 2 of the 2-minute rectangles. The arrangement and numbering of these blocks form the primary divisions of each atlas sheet.

The nine 2-minute rectangles in each of the complete blocks are numbered from 1 to 9, beginning in the upper left-hand corner, and numbered to the right, 4 being on the left under 1. The subdivision of the rectangles for the incomplete blocks at the right are numbered 1, 4, and 7; and those at the bottom 1, 2, 3, 4, 5, and 6; and of block 45 in the lower right corner 1 and 4.

A further subdivision of each of these rectangles into squares and units is necessary in order to fix locations to an area of approximately 30 acres, and these subdivisions are likewise numbered 1 to 9.

If the number of the atlas sheet is followed by the number of each of these smaller divisions or units, each 30 acre parcel in the State acquires a unique 7 digit number. The number enables any point to be located quickly on any atlas sheet.

It is impossible to map a curved Earth on a flat map using plane coordinates (x,y or northing, easting) without distorting angles, distances, or areas. It is possible to design a map projection such that some of the three are undisturbed or minimally distorted. The State Plane Coordinate System (SPCS) is a map projection system that minimizes angular distortions if only a small portion of the earth is flattened out. Thus, the SPCS is a rectangular (x,y or northing, easting) coordinate system describing geodetic positions of a limited area (a state or a portion of it) on a plane. The (x,y) coordinates are computed by projecting latitudes and longitudes from a mathematical approximation of the earth (i.e., NAD83) onto a rectangular grid.

By law, the New Jersey State Plane Coordinate System (based on NAD83) is the official survey base for the State of New Jersey (R.S.51:3-7).

The coordinate reference system North American Datum of 1927 (NAD27) was adopted in 1913 and is based on the Clarke reference ellipsoid. The Geodetic survey station MEADES RANCH in Osborne County, Kansas, was selected as the reference point for this datum.

With the development of global positioning system (GPS), the capability was provided for obtaining more precise positional data. GPS data was "forced" to fit the original NAD27 network, which caused distortions in the positional data.

The development of the NAD83 included both a readjustment of the survey observations and a redefinition of the datum. This new datum was defined using the Geodetic Reference System 1980 (GRS80) as the reference ellipsoid. The GRS80 ellipsoid is geocentric and more closely approximates the true size and shape of the Earth. A readjustment was also done using a simultaneous least-squares method of adjustment to minimize mathematical distortions. This x,y coordinate shift can exceed 400 meters in some parts of the country.

Locations obtained using GPS receivers are in NAD83 as are Digital Ortho Photo quads. Older digital data products such as US Geological Survey (USGS) Digital Line Graph data (digital representation of features found on USGS quad maps) are generally NAD27.

Kümmel, Henry B., 1912, Annual Administrative Report of
the State Geologist for the year 1911, NJGS Bulletin 6, 82 p.

Kümmel, Henry B., 1913, Annual Administrative Report of the State Geologist
for the year 1912, NJGS Bulletin 8, 103 p.