US National Grid (USNG)

Grid Zone Junction and

Truncation/Abbreviation Illustrations

Missoula, MT & Culpeper, VA

2004 N.G. Terry, Jr.©

126° 120° 114° 108° 102° 96° 90° 84° 78° 72° 66°

1011

1213 14 15 16 17

18

19

© 1998 N.G. Terry, Jr. US UTM Zones 10 - 19

UTM Grid Zones

All plane coordinate systems have zone junctions. A characteristic of the UTM system is the minimum number of uniform zones that cover the US while retaining desired attributes. The figures in this brief illustrate how zone junctions do not pose a problem to US National Grid users. This is because the grid is overlaid on the lat/long graticule, and while digital systems (i.e. GPS receivers and GIS) display USNG values for our ease of use, the underlying calculations are using lat/long.

Culpeper, Va

Missoula, MT

114° W. Longitude(Looking due South.)

GZD 11TGZD 12T

820 Emma Ct.12T TS 7148 9714

1723 Ethel Lane11T QM 2854 9714

Missoula, MT

© 2004 N.G. Terry, Jr.

114° W

284282

284282 716 718

972

97 97

972

USNG: 11T QM

USNG: 12T TS

USNG: 12T TS

USNG: 11T QM

GZD

: 11T

GZD

: 12T

716 718

114° West Longitude

820 Emma Ct.12T TS 7148 9714

1723 Ethel Lane11T QM 2854 9714

Missoula, MT 114° W. Longitude

GZD 11TGZD 12T

820 Emma Ct.12T TS 7148 9714

1723 Ethel Lane11T QM 2854 9714

Missoula, MT

GZD 11T

GZD 12T

© 2004 N.G. Terry, Jr.

284 716

Scale:100m

GZD 11TGZD 12T114° W. Long.

501 W. Broadway11T QM 2857 9552

Knuckleheads BBQ450 W. Broadway12T TS 7142 9553

Missoula, MontanaGrid Zone junction between Zones 11 and 12

While adjacent, within feet of the zone junction,each business has its own absolute geoaddress.

© 2004 N.G. Terry, Jr.

114°W 72 96

957228

95

96

78° W

UTM Zone 18SUTM Zone 17S

18STH38286229217 Chandler St. West

Culpeper, VA

17SQC617623601 Blue Ridge Ave. S.

Culpeper, VA

If you were to walk east and west along Chandler Street with a GPS receiver, crossing the 78°West meridian, you would see the Grid Zone Designation change automatically between 17S and 18S. This is because the location calculations are being made in lat/long, and translated on the fly for presentation as USNG values which are easier to use on maps at larger scales.

2000 Tom Terry©

US National Grid at Zone Junctions

Culpepper, VA 78° W 18S TH

616 384

622

624

614 386

GPS receivers, like the software this map was displayed with, automatically present the correct zone in the coordinate readout when users crosszone junctions. Thus a junction, while offering a‘zipper-like’ appearance on maps, does not

pose obstacles or problems for US National Grid users and geoaddressing.

17S QC 18S TH

© 1999 N.G. Terry, Jr.

The Power of Truncated UTM/USNG ValuesMeades Ranch, KS;

Grid: 14SNJ39524174

RegionalLevel

= Approximate locations of nearest pointsthat have the value NJ39524174

Back Up Slides

601 Blue Ridge Ave., South17SQC617623

217 Chandler St., West18STH38286229

US National Grid (USNG), Geoaddressing, and Zone Junctions.GZD: 17S

100,000-m Sq. ID: QCGZD: 18S

100,000-m Sq. ID: TH

Grid Zone Designation = GZDGrid: NAD 27

GPS receivers, like the software this map was displayed with, automatically present the correct zone in the coordinate readout when users cross zone junctions. Thus a junction, while offering a ‘zipper-like’ appearance on maps, does not pose obstacles or problems for US National Grid users and geoaddressing.

(Note: The grid on these USGS maps have not yet been updated from NAD27 to NAD83. The USNG values above, for the houses [in red circles] are referenced to NAD 83.) The USNG values referenced to NAD 27 are:601 Blue Ridge Ave., South: 17SQC61686208217 Chandler St., West: 17SQC61716207

GPS receivers, like the software this map was displayed with, automatically present the correct zone in the coordinate readout when users cross zone junctions. Thus a junction, while offering a ‘zipper-like’ appearance on maps, does not pose obstacles or problems for US National Grid users and geoaddressing.

(Note: The grid on these USGS maps have not yet been updated from NAD27 to NAD83. The USNG values above, for the houses [in red circles] are referenced to NAD 83.) The USNG values referenced to NAD 27 are:601 Blue Ridge Ave., South: 17SQC61686208217 Chandler St., West: 17SQC61716207

61

761000mE 39

6262

Printed from Topo! © 2000 National Geographic Holdings (www.topo.com)

240000mE

42634263

78°W

78°W