United States National Grid (Final Draft)
Transcript of United States National Grid (Final Draft)
Federal Geographic Data Committee
Department of Agriculture, Department of Commerce, Department of Defense, Department of Energy Department of Housing and Urban Development, Department of the Interior, Department of State
Department of Transportation, Environmental Protection Agency Federal Emergency Management Agency, Library of Congress
National Aeronautics and Space Administration, National Archives and Records Administration Tennessee Valley Authority
FGDC Document Number 1 2 3
4 5
United States National Grid 6
(Final Draft) 7
8
9
10
Standards Working Group 11 Federal Geographic Data Committee 12
13
September, 2001 14
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32
NSDI
National Spatial Data Infrastructure
NSDI
National Spatial Data Infrastructure
ii
Federal Geographic Data Committee 33 34 Established by Office of Management and Budget Circular A-16, the Federal Geographic Data Committee 35 (FGDC) promotes the coordinated development, use, sharing, and dissemination of geographic data. 36 37 The FGDC is composed of representatives from the Departments of Agriculture, Commerce, Energy, 38 Housing and Urban Development, the Interior, State, and Transportation; the Environmental Protection 39 Agency; the Federal Emergency Management Agency; the Library of Congress; the National Aeronautics 40 and Space Administration; the National Archives and Records Administration; and the Tennessee Valley 41 Authority. Additional Federal agencies participate on FGDC subcommittees and working groups. The 42 Department of the Interior chairs the committee. 43 44 FGDC subcommittees work on issues related to data categories coordinated under the circular. 45 Subcommittees establish and implement standards for data content, quality, and transfer; encourage the 46 exchange of information and the transfer of data; and organize the collection of geographic data to reduce 47 duplication of effort. Working groups are established for issues that transcend data categories. 48 49 For more information about the committee, or to be added to the committee’s newsletter mailing list, please 50 contact: 51 52
Federal Geographic Data Committee Secretariat 53 c/o U.S. Geological Survey 54
590 National Center 55 12201 Sunrise Valley Drive 56
Reston, Virginia 22092 57 58
Telephone: (703) 648-5514 59 Facsimile: (703) 648-5755 60
Internet (electronic mail): [email protected] 61 Anonymous FTP: www.fgdc.gov/pub/ 62
home page: www.fgdc.gov 63 64 The following is the recommended bibliographic citation for this publication: 65 66 United States National Grid (USNG), 67 FGDC, September 2001, Reston, Virginia. 68
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69 CONTENTS 70
Page 71 1. Introduction................................................................................................................................................ 1 72
1.1 Objective.................................................................................................................................... 1 73 1.2 Scope ......................................................................................................................................... 2 74 1.3 Applicability .............................................................................................................................. 2 75 1.4 Related Standards ...................................................................................................................... 4 76 1.5 Standards Development Process ................................................................................................ 4 77 1.6 Maintenance Authority .............................................................................................................. 5 78
2. Conformance.............................................................................................................................................. 6 79 3. Main Features and Specifications............................................................................................................... 7 80
3.1 Equivalency with MGRS ........................................................................................................... 7 81 3.2 Basic Numbering ....................................................................................................................... 7 82 3.3 Referencing Scheme .................................................................................................................. 7 83
3.3.1.Grid Zone Designation ............................................................................................. 7 84 3.3.2 100,000-meter Square Identification ........................................................................ 9 85 3.3.3 Grid Coordinates ...................................................................................................... 9 86
4. Relationship to Datums .............................................................................................................................12 87 5. Accuracy and Precision.............................................................................................................................12 88
5.1 Accuracy...................................................................................................................................12 89 5.2 Precision ...................................................................................................................................12 90
5.2.1 Field Applications ...................................................................................................12 91 5.2.2 Special Applications................................................................................................12 92
6. References.................................................................................................................................................14 93 Annex A (Normative) Use of North American Datum 1927 (NAD 27)........................................................15 94 Annex B (Normative) Truncation of UTM Coordinate Values.....................................................................17 95 Annex C (Informative) USNG Implementations...........................................................................................19 96
C.1 Applications .............................................................................................................................20 97 C.1.1 General Features .....................................................................................................20 98 C.1.2 Large Geographic Areas .........................................................................................20 99 C.1.3 Regional Areas........................................................................................................20 100 C.1.4 Local Areas .............................................................................................................21 101 C.1.5 Local Areas Near Grid Zone and/or 100,000-meter Square Boundaries ................21 102 C.1.6 Complete Grid Reference........................................................................................21 103 C.1.7 Reading Grid Coordinates.......................................................................................24 104
Annex D (Informative) General Conventions for USNG..............................................................................32 105 D.1 Appropriate Use of Truncated Values......................................................................................33 106 D.2 Geographic Indexing................................................................................................................34 107
D.2.1 National Atlas or Map ............................................................................................34 108 D.2.2 State Map Index......................................................................................................34 109 D.2.3 City Street Index.....................................................................................................35 110
D.3 Portrayal of USNG Grids and Grid Values on Maps ...............................................................35 111 D.3.1 Grid Spacing...........................................................................................................35 112 D.3.2 Grid Value Portrayal...............................................................................................37 113 D.3.3 Grid Reference Box ................................................................................................37 114 D.3.4 Map Legend Information ........................................................................................37 115
Annex E (Informative) USNG Standardized Numbering for NAD 27 Maps................................................39 116 Annex F (Informative) Glossary ...................................................................................................................41 117 118
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Figures 119 Page 120
Figure 1 GZDs of the USNG .......................................................................................................... 8 121 Figure 2 Basic Plan of the 100,000-meter Square Identifications of the USNG............................10 122 Figure 3 Organization of the USNG 100,000-meter squares .........................................................11 123 Figure 4 Methods for showing GZDs and 100,000-meter Squares of the USNG in the 124
Grid Reference Box ........................................................................................................22 125 Figure 5 Sample Grid Reference Box with instructions for giving a complete reference ..............23 126 Figure 6 USNG Principal Digits ....................................................................................................25 127 Figure 7 Convention for portrayal of grid lines, UTM values, and single USNG 100,000-meter 128
Square Identification.......................................................................................................26 129 Figure 8 Convention for portrayal of grid lines, UTM values, and multiple USNG 130
100,000-meter Square Identifications .............................................................................27 131 Figure 9 How to read USNG grid coordinates (1:24,000) .............................................................31 132 133 134
135 Tables 136 Table 1 Truncation of USNG Values.............................................................................................18 137 Table 2 Grid Spacing Recommendation ........................................................................................36138
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1. INTRODUCTION 139 140
1.1 Objective 141 142
The objective of this standard is to create a more favorable environment for developing location-143
based services within the United States and to increase the interoperability of location services 144
appliances with printed map products by establishing a nationally consistent grid reference system 145
as the preferred grid for National Spatial Data Infrastructure (NSDI) applications. This standard 146
defines the US National Grid. The U.S. National Grid is based on universally defined coordinate 147
and grid systems and can, therefore, be easily extended for use world-wide as a universal grid 148
reference system. 149
150
There are a number of coordinate reference systems that can be used either in location service 151
appliances or on printed maps for the purpose of establishing a location. Within automated 152
location service appliances, the conversion of coordinates based on one well-defined reference 153
system to coordinates based on another can be both automatic and transparent to the user. These 154
devices can support multiple coordinate reference systems with little difficulty. However, it is not 155
easy for humans to work in multiple reference systems and humans cannot convert between 156
systems without the aid of location service appliances, calculators, or conversion tables. 157
Furthermore, it is difficult for humans to accurately determine a location coordinate from paper 158
maps when latitude and longitude are used because they do not appear square on the flat map. As a 159
consequence paper maps created for the general public frequently have a square reference grid that 160
overlays the non-rectangular coordinate reference system. It is computationally difficult, labor 161
intensive, and time consuming to convert the reference grid coordinate obtained from one printed 162
map to another printed map with a different grid even when both grid reference systems are well 163
defined. It can be impossible when proprietary grids are used. This situation greatly limits the 164
ability of humans to use location service devices with traditional printed maps. Subsequently, 165
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location based services in this country have been limited to totally digital environments, restricting 166
the number of uses and retarding the development of the location based service industry. 167
168
This standard seeks to improve the current situation by identifying a single nationally consistent, 169
humanly facile grid reference system as the preferred U.S. National Grid (USNG) and promoting 170
its use within the NSDI. 171
172 1.2 Scope 173
174
This standard defines a preferred U.S. National Grid (USNG) for mapping applications at scales of 175
approximately 1:1,000,000 and larger. It defines how to present Universal Transverse Mercator 176
(UTM) coordinates at various levels of precision. It specifies the use of those coordinates with the 177
grid system defined by the Military Grid Reference System (MGRS). Additionally, it addresses 178
specific presentation issues such as grid spacing. The UTM coordinate representation, the MGRS 179
grid, and the specific grid presentation requirements together define the USNG. This standard is a 180
process standard as defined by the Federal Geographic Data Committee (FGDC) Standards 181
Reference Model. Specifically, it is a presentation process standard. 182
183
1.3 Applicability 184
185
This standard is for use in the acquisition or production, either directly or indirectly through 186
contracts and partnerships, of printed maps and the acquisition, either directly or indirectly, of 187
location service appliances. The USNG addresses the geospatial coordinate, human interface of 188
products and services designed as interoperable components of the NSDI. This standard applies to 189
printed maps that are intended to be used or are likely to be used by humans in conjunction with 190
location service appliances and to location service appliances that are intended to be used or are 191
likely to be used by humans in conjunction with printed map products. 192
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193
This standard is not primarily intended for the collection of geospatial data, either remote sensed 194
data collection or field surveys. Nor is it intended for internal data storage structure of any 195
Geographic Information System (GIS) or location service appliance or to the transfer of 196
coordinates between databases or appliances. 197
198
Use of USNG grid coordinates may be useful or even desirable within some systems or enterprises. 199
The decision to use USNG grid coordinates or some other coordinate system internal to 200
geographic information systems or location service appliances is left to the discretion of the system 201
developer as long as the human interface provides for USNG grid coordinate readout as one 202
option. 203
204
The USNG is not designed for surveying. This standard is not intended to replace the State Plane 205
Coordinate Systems (SPCS) established by the National Geodetic Survey. The SPCS is 206
specifically designed to meet the requirements of surveyors and engineers in determining location 207
and boundaries and some states mandate its use for specific purposes. SPCS coordinates can be 208
readily converted to USNG grid coordinates for subsequent use within the NSDI. The state plane 209
coordinate system (SPCS), Public Land Survey System (PLSS) and other accepted local spatial 210
reference systems may continue to be used where preferred for property descriptions and other 211
specialized uses. 212
213
The USNG is interoperable with the MGRS. This will be of critical importance to safety of life 214
during times of disaster relief operations. 215
216
217
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1.4 Related Standards 217
218
This standard is compatible with: 219
220
• ANSI X3.61-1986, Representation of Geographic Point Locations for Information 221
Interchange, which standardizes representation of UTM coordinates for computer 222
representation. 223
224
• ISO/DIS 19116, Positioning Services, which provides an interface for real-time output from a 225
GPS receiver and other positioning technologies. 226
227
• ISO/DIS 19111, Spatial Referencing by Geographic Coordinates, which provides a conceptual 228
schema for the description of coordinate reference systems. 229
230
• The USNG standard is based on the Military Grid Reference System 231
232
1.5 Standards Development Process 233
234
The USNG is an initiative of the Public XY Mapping Project, which is a not-for-profit 235
organization created specifically to promote the acceptance of a national grid for the United States. 236
The original concept can be traced to discussions within the American Society for Photogrammetry 237
and Remote Sensing. The Public XY Mapping Project developed the idea, conducting informal 238
tests and surveys to determine which coordinate reference system best met the requirements of 239
national consistency and ease of human use. Based on its findings, a standard based on the MGRS 240
was adopted. 241
242
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Because of the importance of this project to the NSDI, the Public XY Project brought its findings 243
to the FGDC in 1998. After briefing the FGDC Coordination Group, an ad hoc study group, that 244
included the FGDC Staff Director and the Chair of the FGDC Standards Working Group, 245
recommended that the FGDC accept the project as an FGDC standard development activity. The 246
FGDC Standards Working Group then created a subgroup led by the Public XY Mapping Project 247
to husband the project through the FGDC standards process. The subgroup contains members 248
from both the public and private sector, including key participation from the National Imagery and 249
Mapping Agency (NIMA) to assure that the USNG retains interoperability with the MGRS. The 250
subgroup refined the standard and through an iterative review process with the FGDC Standards 251
Working Group, produced, in November 2000, a final draft for public review consistent with the 252
FGDC standards directives. 253
254
1.6 Maintenance Authority 255
256
The Public XY Mapping Project will maintain this standard for the first five years. The Public XY 257
Mapping Project has demonstrated the ability to marshal the resources needed to develop, 258
promote, and initially implement the standard. After five years, the FGDC Standards Working 259
Group will evaluate the need to move maintenance responsibility to one of the FGDC agencies. 260
261
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2. CONFORMANCE 261
262
Location service appliances that claim conformance to this standard shall accept USNG 263
coordinates, as defined in Section 3, as input from the human user and provide USNG coordinate 264
output to the human user, as at least one option. 265
266
Printed map products that claim conformance to this standard shall provide a means for humans to 267
accurately locate a USNG coordinate on the map and for humans to extract, for any point on the 268
map, an accurate USNG coordinate. This will usually mean that the USNG will be printed on the 269
map according to the guidance in this specification. 270
271
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3. MAIN FEATUES AND SPECIFICATIONS. 271
272
3.1 Equivalency With MGRS 273
274
USNG coordinates shall be identical to the MGRS numbering scheme over all areas of the United 275
States including outlying territories and possessions. 276
277
3.2 Basic Numbering 278
279
USNG basic coordinate values and numbering are identical to UTM coordinate values over all 280
areas of the United States including outlying territories and possessions. 281
282
3.3 Referencing Scheme 283
284
Numbering scheme shall be alphanumeric as follows: 285
286
3.3.1 Grid Zone Designation 287
288
First, the U.S. geographic area shall be divided into 6-degree longitudinal zones designated by a 289
number and 8-degree latitudinal bands designated by a letter. Thus each area is given a unique 290
alphanumeric Grid Zone Designator (GZD) (Figure 1 – pg. 8). 291
292
The longitude zone numbers and latitude band letters for GZD over the United States shall be 293
taken from the global scheme of MGRS. 294
295
18S – Identifies a GZD. 296
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Figure 1. Grid Zone Designations of the U.S. National Grid (USNG)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60CDE
FG
HJ
KL
M
N
PQ
RS
T
U
V
W
X
80°72°
64°56°
48°
40°32°
24°
16°8°
0°
8°
16°24°
32°
40°48°56°
64°72°
84°
174°
180°
168°
162°
156°
150°
144°
138°
132°
126°
120°
114°
108°
102°
96°
90°
84°
78°
54°
48°
42°
36°
30°
24°
18°
0°12°
6° 6° 12°
18°
24°
30°
36°
42°
48°
54°
60°
66°
66°
72°
Grid Zone Designation 18S
174°
180°
168°
162°
156°
150°
144°
138°
132°
126°
120°
114°
108°
102°
96°
90°
84°
78°
72°
A B90°W 90°E
180°
0°
0°
Y Z
180°
90°E90°W
60°
297
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298
3.3.2 100,000-meter Square Identification 299
300
Each GZD 6x8 degree area shall be covered by a specific scheme of 100,000-meter squares where 301
a two-letter pair identifies each square (Figures 2 and 3 – pgs. 10 and 11). 302
303
18SUJ – Identifies a specific 100,000-meter square in the specified GZD. 304
305
306
3.3.3 Grid Coordinates 307
308
A point position within the 100,000-meter square shall be given by the UTM grid coordinates in 309
terms of its Easting (E) and Northing (N). For specific requirements or applications, the number of 310
digits will depend on the precision desired in position referencing. In this convention, the reading 311
shall be from left with Easting first, then Northing. An equal number of digits shall always be used 312
for E and N. 313
Examples: 314
18SUJ20 - Locates a point with a precision of 10 km 315
18SUJ2306 - Locates a point with a precision of 1 km 316
18SUJ234064 - Locates a point with a precision of 100 meters 317
18SUJ23480647 - Locates a point with a precision of 10 meters 318
18SUJ2348306479 - Locates a point with a precision of 1 meter 319
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Figure 2. Basic Plan of the 100,000-meter Square Identification of the United States National Grid (USNG)
BM CM DM EM FM GM
BL CL DL EL FL GL
BK CK DK EK FK GK
BJ CJ DJ EJ FJ GJ
BH CH DH EH FH GH
BG CG DG EG FG GG
BF CF DF EF FF GF
BE CE DE EE FE GE
BD CD DD ED FD GD
BC CC DC EC FC GC
BB CB DB EB FB GB
BA CA DA EA FA GA
BG CG DG EG FG GG
BF CF DF EF FF GF
BE CE DE EE FE GE
BD CD DD ED FD GD
BC CC DC EC FC GC
BB CB DB EB FB GB
BA CA DA EA FA GA
BV CV DV EV FV GV
BU CU DU EU FU GU
BT CT DT ET FT GT
BS CS DS ES FS GS
BR CR DR ER FR GR
BQ CQ DQ EQ FQ GQ
BP CP DP EP FP GP
BN CN DN EN FN GN
KM LM MM NM PM QM
KL LL ML NL PL QL
KK LK MK NK PK QK
KJ LJ MJ NJ PJ QJ
KH LH MH NH PH QH
KG LG MG NG PG QG
KF LF MF NF PF QF
KE LE ME NE PE QE
KD LD MD ND PD QD
KC LC MC NC PC QC
KB LB MB NB PB QB
KA LA MA NA PA QA
KV LV MV NV PV QV
KU LU MU NU PU QU
KT LT MT NT PT QT
KS LS MS NS PS QS
KR LR MR NR PR QR
KQ LQ MQ NQ PQ QQ
KP LP MP NP PP QP
KN LN MN NN PN QN
KM LM MM NM PM QM
KL LL ML NL PL QL
KK LK MK NK PK QK
KJ LJ MJ NJ PJ QJ
KH LH MH NH PH QH
KG LG MG NG PG QG
KF LF MF NF PF QF
TM UM VM WM XM YM
TL UL VL WL XL YL
TK UK VK WK XK YK
TJ UJ VJ WJ XJ YJ
TH UH VH WH XH YH
TG UG VG WG XG YG
TF UF VF WF XF YF
TE UE VE WE XE YE
TD UD VD WD XD YD
TC UC VC WC XC YC
TB UB VB WB XB YB
TA UA VA WA XA YA
TG UG VG WG XG YG
TF UF VF WF XF YF
TE UE VE WE XE YE
TD UD VD WD XD YD
TC UC VC WC XC YC
TB UB VB WB XB YB
TA UA VA WA XA YA
TV UV VV WV XV YV
TU UU VU WU XU YU
TT UT VT WT XT YT
TS US VS WS XS YS
TR UR VR WR XR YR
TQ UQ VQ WQ XQ YQ
TP UP VP WP XP YP
TN UN VN WN XN YN
AM
AL
AK
AJ
AH
AG
AF
AE
AD
AC
AB
AA
AG
AF
AE
AD
AC
AB
AA
AV
AU
AT
AS
AR
AQ
AP
AN
HM
HL
HK
HJ
HH
HG
HF
HE
HD
HC
HB
HA
HG
HF
HE
HD
HC
HB
HA
HV
HU
HT
HS
HR
HQ
HP
HN
JM
JL
JK
JJ
JH
JG
JF
JE
JD
JC
JB
JA
JV
JU
JT
JS
JR
JQ
JP
JN
JM
JL
JK
JJ
JH
JG
JF
RS
RR
RQ
RP
RN
RM
RL
RK
RJ
RH
RG
RF
RM
RL
RK
RJ
RH
RG
RF
RE
RD
RC
RB
RA
RV
RU
RT
SM
SL
SK
SJ
SH
SG
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SE
SD
SC
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SA
SG
SF
SE
SD
SC
SB
SA
SV
SU
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SR
SQ
SP
SN
ZM
ZL
ZK
ZJ
ZH
ZG
ZF
ZE
ZD
ZC
ZB
ZA
ZG
ZF
ZE
ZD
ZC
ZB
ZA
ZV
ZU
ZT
ZS
ZR
ZQ
ZP
ZN
1,000,000m
8°
0°180° 500,000m
False Easting174° 168°
162°0°
8°
1,000,000m
2,000,000m2,000,000m
16°16°
24°162°168°174°180°
24°
0m 0m
500,000mFalse Easting
500,000mFalse Easting
320
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Figure 3. Organization of the U.S. National Grid (USNG) 100,000-meter Grid Squares
AV BV CV DV EV FV GV HV JE KE LE ME NE PE QE RE SV TV UV VV WV XV YV ZV
AU BU CU DU EU FU GU HU JD KD LD MD ND PD QD RD SU TU UU VU WU XU YU ZU
AT BT CT DT ET FT GT HT JC KC LC MC NC PC QC RC ST TT UT VT WT XT YT ZT
AS BS CS DS ES FS GS HS JB KB LB MB NB PB QB RB SS TS US VS WS XS YS ZS
AR BR CR DR ER FR GR HR JA KA LA MA NA PA QA RA SR TR UR VR WR XR YR ZR
AQ BQ CQ DQ EQ FQ GQ HQ JV KV LV MV NV PV QV RV SQ TQ UQ VQ WQ XQ YQ ZQ
AP BP CP DP EP FP GP HP JU KU LU MU NU PU QU RU SP TP UP VP WP XP YP ZP
AN BN CN DN EN FN GN HN JT KT LT MT NT PT QT RT SN TN UN VN WN XN YN ZN
AM BM CM DM EM FM GM HM JS KS LS MS NS PS QS RS SM TM UM VM WM XM YM ZM
AL BL CL DL EL FL GL HL JR KR LR MR NR PR QR RR SL TL UL VL WL XL YL ZL
AK BK CK DK EK FK GK HK JQ KQ LQ MQ NQ PQ QQ RQ SK TK UK VK WK XK YK ZK
AJ BJ CJ DJ EJ FJ GJ HJ JP KP LP MP NP PP QP RP SJ TJ UJ VJ WJ XJ YJ ZJ
AH BH CH DH EH FH GH HH JN KN LN MN NN PN QN RN SH TH UH VH WH XH YH ZH
AG BG CG DG EG FG GG HG JM KM LM MM NM PM QM RM SG TG UG VG WG XG YG ZG
AF BF CF DF EF FF GF HF JL KL LL ML NL PL QL RL SF TF UF VF WF XF YF ZF
AE BE CE DE EE FE GE HE JK KK LK MK NK PK QK RK SE TE UE VE WE XE YE ZE
AD BD CD DD ED FD GD HD JJ KJ LJ MJ NJ PJ QJ RJ SD TD UD VD WD XD YD ZD
AC BC CC DC EC FC GC HC JH KH LH MH NH PH QH RH SC TC UC VC WC XC YC ZC
AB BB CB DB EB FB GB HB JG KG LG MG NG PG QG RG SB TB UB VB WB XB YB ZB
AA BA CA DA EA FA GA HA JF KF LF MF NF PF QF RF SA TA UA VA WA XA YA ZA
AE BE CE DE EE FE GE HE JV KV LV MV NV PV QV RV SE TE UE VE WE XE YE ZE
AD BD CD DD ED FD GD HD JU KU LU MU NU PU QU RU SD TD UD VD WD XD YD ZD
AC BC CC DC EC FC GC HC JT KT LT MT NT PT QT RT SC TC UC VC WC XC YC ZC
AB BB CB DB EB FB GB HB JS KS LS MS NS PS QS RS SB TB UB VB WB XB YB ZB
AA BA CA DA EA FA GA HA JR KR LR MR NR PR QR RR SA TA UA VA WA XA YA ZA
AV BV CV DV EV FV GV HV JQ KQ LQ MQ NQ PQ QQ RQ SV TV UV VV WV XV YV ZV
AU BU CU DU EU FU GU HU JP KP LP MP NP PP QP RP SU TU UU VU WU XU YU ZU
AT BT CT DT ET FT GT HT JN KN LN MN NN PN QN RN ST TT UT VT WT XT YT ZT
AS BS CS DS ES FS GS HS JM KM LM MM NM PM QM RM SS TS US VS WS XS YS ZS
AR BR CR DR ER FR GR HR JL KL LL ML NL PL QL RL SR TR UR VR WR XR YR ZR
AQ BQ CQ DQ EQ FQ GQ HQ JK KK LK MK NK PK QK RK SQ TQ UQ VQ WQ XQ YQ ZQ
AP BP CP DP EP FP GP HP JJ KJ LJ MJ NJ PJ QJ RJ SP TP UP VP WP XP YP ZP
AN BN CN DN EN FN GN HN JH KH LH MH NH PH QH RH SN TN UN VN WN XN YN ZN
AM BM CM DM EM FM GM HM JG KG LG MG NG PG QG RG SM TM UM VM WM XM YM ZM
AL BL CL DL EL FL GL HL JF KF LF MF NF PF QF RF SL TL UL VL WL XL YL ZL
AK BK CK DK EK FK GK HK JE KE LE ME NE PE QE RE SK TK UK VK WK XK YK ZK
AJ BJ CJ DJ EJ FJ GJ HJ JD KD LD MD ND PD QD RD SJ TJ UJ VJ WJ XJ YJ ZJ
AH BH CH DH EH FH GH HH JC KC LC MC NC PC QC RC SH TH UH VH WH XH YH ZH
AG BG CG DG EG FG GG HG JB KB LB MB NB PB QB RB SG TG UG VG WG XG YG ZG
AF BF CF DF EF FF GF HF JA KA LA MA NA PA QA RA SF TF UF VF WF XF YF ZF
2,000,000 m
ZONES
1,000,000 m
500,000 m
0 m
1,500,000 m
SET 11, 7, 13, 19, 25, 31,
37, 43, 49, 55
SET 22, 8, 14, 20, 26, 32,
38, 44, 50, 56
200,
000
m
300,
000
400,
000
500,
000
600,
000
700,
000
800,
000
m
SET 33, 9, 15, 21, 27, 33,
39, 45, 51, 57
SET 44, 10, 16, 22, 28, 34,
40, 46, 52, 58
SET 55, 11, 17, 23, 29, 35,
41, 47, 53, 59
SET 66, 12, 18, 24, 30, 36,
42, 48, 54, 60
200,
000
m
300,
000
400,
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500,
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m
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200,
000
m
300,
000
400,
000
500,
000
600,
000
700,
000
800,
000
m
200,
000
m
300,
000
400,
000
500,
000
600,
000
700,
000
800,
000
m
321
Federal Geographic Data Committee XXX United States National Grid
12
4. RELATIONSHIP TO DATUMS 322
323
The standard datum for USNG coordinates shall be the North American Datum 1983 (NAD 83) or 324
its international equivalent, the World Geodetic System 1984 (WGS 84). 325
326
For practical applications using an existing map referenced to North American Datum 1927 (NAD 327
27), see Annex A. 328
329
5. ACCURACY AND PRECISION 330
331
5.1 Accuracy 332
333
Paper maps using the USNG grid shall conform to the National Map Accuracy Standard. 334
335
5.2 Precision 336
337
USNG provides a flexible numbering scheme to accommodate variable precision from tens of 338
kilometers to one meter or higher. 339
340
5.2.1 Field Applications 341
For general field applications, a precision of one hundred or ten meters will be typical. 342
For general applications, precision of up to one meter may be used. 343
344
5.2.2 Special Applications 345
346
For special applications, the USNG can provide precision greater than one meter. 347
348
Federal Geographic Data Committee XXX United States National Grid
13
For example, the location of the Washington Monument in Washington, DC can be identified on 349
NAD 83 datum. 350
351
General reference: 18SUJ23480647 – precision 10 meters. 352
Special application: 18SUJ2348316806479498 – precision 1 millimeter. 353
354
Federal Geographic Data Committee XXX United States National Grid
14
6. REFERENCES 354
355
American National Standards Institute, Inc. (ANSI), 1986, American National Standard for 356
Information Systems - X3.61-1986, Representation of Geographic Point Locations for Information 357
Interchange (Formerly Federal Information Processing Standard 70-1) 358
359
National Imagery and Mapping Agency (NIMA), 1990, DMA Technical Manual 8358.1 Datums, 360
Ellipsoids, Grids, and Grid Reference Systems, Edition 1 361
362
Synder, John P., 1987, Map Projections - A Working Manual; U.S. Geological Survey 363
Professional Paper 1395, US Government Printing Office, Washington, DC 364
365
Thompson, M.M., 1979, Maps for America, US Government Printing Office, Washington, DC366
Federal Geographic Data Committee XXX United States National Grid Annex A – Use of North American Datum 1927 (NAD 27)
15
367
368
369
370
371
United States National Grid 372
Annex A (Normative) 373
Use of North American Datum 1927 (NAD27)374
Federal Geographic Data Committee XXX United States National Grid Annex A – Use of North American Datum 1927 (NAD 27)
16
ANNEX A (Normative) 375
Use of North American Datum 1927 (NAD 27) 376
377
Published spatial references, such as a database or published list of spatial values for point 378
features, shall be referenced to NAD 83 whenever possible. When it is necessary to identify a 379
point on NAD 27, the coordinate values shall be followed by (NAD 27). For example, the NAD 83 380
coordinates of a point are designated 18SUJ23480647, while the NAD 27 coordinates of the same 381
point are designated 18SUJ23450626 (NAD 27). 382
383
384
385
Federal Geographic Data Committee XXX United States National Grid Annex B – Truncation of USNG Values
17
386
387
388
389
390
United States National Grid 391
Annex B (Normative) 392
Truncation of USNG Coordinate Values393
Federal Geographic Data Committee XXX United States National Grid Annex B – Truncation of USNG Values
18
ANNEX B (Normative) 394
Truncation of USNG Coordinate Values 395
396
A uniform system of truncation is adopted for the USNG1. Truncated coordinates begin with the 10,000-397
meter digit. Truncated coordinate values shall always consist of an even number of digits. Table 1 398
demonstrates how to truncate USNG grid coordinate values and compares these with truncated UTM grid 399
coordinates. The portions of the USNG grid coordinate that is imbedded in the UTM coordinate value are 400
underlined for illustrative purposes. 401
402
Table 1. Truncation of USNG values Examples of truncated grid coordinates 403
Truncated coordinates Complete grid reference
Four digit
(1 km)
Six digit
(100 m)
Eight digit
(10 m)
Ten digit
(1 m)
UTM +18,323483.168,4306479.498 2306 234064 23480647 2348306479
USNG 18SUJ2348306479 2306 234064 23480647 2348306479
404 1 A similar system of coordinate truncation can be employed for UTM grid coordinates. However, such a system of truncation is not part of the definition of the UTM system or the coordinate representation standard, ANSI X3.61, and is included here in Table 1 for illustration and uniformity purposes.
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
19
404
405
406
407
408
United States National Grid 409
Annex C (Informative) 410
USNG Implementations411
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
20
ANNEX C (Informative) 412
USNG Implementations 413
414
C.1 Applications 415
416
C.1.1 General features 417
418
All elements of a grid reference need not be used. Their use depends upon the size of the area of 419
activities, the type of use, and the scale of map to which the reference is keyed. Users will decide 420
which elements of the grid references are needed for specific circumstances. The following 421
paragraphs provide guidance for the use of GZDs and 100,000-meter Square Identifications. 422
423
C.1.2 Large geographic areas 424
425
For situations or issues spanning large geographical areas, such as conterminous United States or 426
Alaska, the GZD is usually given (such as 18S in 18SUJ23480647). The designation will alleviate 427
ambiguity between identical references that may occur when reporting to a station outside the area. 428
The GZD is always used in giving references on 1:1,000,000-scale to 1:500,000 scale maps. 429
430
C.1.3 Regional areas 431
432
For areas less than a grid zone wide, but exceeding 100,000 meters, only the 100,000-meter Square 433
Identification need be used (such as UJ in UJ23480647). 434
435
436
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
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C.1.4 Local areas 436
437
For small and localized areas, the GZDs and 100,000-meter Square Identifications need not be 438
used, unless reporting falls within the parameters explained in following paragraphs. For an area 439
falling within a single 100,000-meter square, only the numerical part of the grid reference is 440
required (such as 23480647). 441
442
C.1.5 For local areas near Grid Zone and/or 100,000-meter Square boundaries 443
444
C.1.5.1 Grid Zone Boundary 445
446
In this case, GZD and 100,000-meter Square Identification have to be used with the USNG 447
coordinate. 448
449
C.1.5.2 100,000-meter Square Boundary 450
451
In this case, the 100,000-meter Square Identification has to be used with the USNG coordinate. 452
453
C.1.6 Complete grid reference 454
455
Topographic maps at 1:500,000 and larger scales should provide a grid reference box that contains 456
the elements for making a complete grid reference. See Figure 4 (pg. 22). Figure 5 (pg. 23) 457
provides an example of an option for a grid reference box with instructions for making a complete 458
grid reference. 459
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
22
Figure 4. Methods for depicting Grid Zone Designations and 100,000-meter Square Identificationson the US National Grid in the Grid Reference Box.
Grid Zone Designation18S
43 00
UH
UJ
100,000-m Square ID
U.S. National Grid
Grid Zone Designation18S
UH
100,000-m Square ID
U.S. National Grid
Grid Zone Designation18S
3 00
43 00
TH
TJ
UH
UJ
100,000-m Square ID
U.S. National Grid
UK
100,000-m Square ID
18S
Grid Zone Designation
18T40°N
U.S. National Grid
QC
100,000-m Square ID
TH
78°WGrid Zone Designation
17S 18S
78°W
U.S. National Grid
Grid Zone Designation18S
3 00
TJ UJ
100,000-m Square ID
U.S. National Grid
UK
Grid Zone Designation
18S
18T40°N
4 00
VK
100,000-m Square ID
U.S. National Grid
QE TK
100,000-m Square ID
Grid Zone Designation
17T 18T
78°W17S 18S
40°N
U.S. National GridU.S. National Grid
Grid Zone Designation
04Q 05Q
156°W
23 00HH
HJ
JC
JD
100,000-m Square ID
156°W
460
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
23
1. Read numbers labeling the VERTICAL grid line left of pointand estimate tenths (100 meters) from grid line to point.
2. Read numbers labeling the HORIZONTAL grid line below pointand estimate tenths (100 meters) from grid line to point.
95 4
92 6
WHEN REPORTING ACROSS A 100,000 METER LINE, PREFIXTHE 100,000 METER SQUARE IDENTIFICATION IN WHICH THE POINT LIES.
Example: 954926
Example: TH954926
WHEN REPORTING OUTSIDE THE GRID ZONE DESIGNATIONAREA, PREFIX THE GRID ZONE DESIGNATION.
Example: 18STH954926
Grid Zone Designation18S
100,000-m Square ID
Samplepoint
95 9692
93
TH
Figure 5. Sample Grid Reference Box with instructions for giving a complete reference.
461
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
24
C.1.7 Reading grid coordinates 462
463
C.1.7.1 Principal digits 464
465
The 10,000-meter and 1,000-meter digits are known as the principal digits and identify USNG grid 466
lines. Preceding and following UTM digits are shown as superscript. Alternatively, only the 467
principal digits for grid lines need be shown, but a sample full UTM value for both the Easting and 468
Northing axis must be depicted at least once on the map, usually near the southeast corner. See 469
Figures 6, 7 and 8 (pgs 25 – 27). 470
471
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
25
Figure 6. United States National Grid (USNG) Principal Digits.
The 10,000 and 1,000 meter values in UTM coordinates are known as the principal digits in USNG coordinates. In this illustration, six examples of Principal Digits have been circled. Note how the USNG principal digits are portrayed in larger type, and the preceding and post principal digit UTM values are included as superscript. This well established convention provides both USNG and UTM values in a manner that is easy to read and prevents confusion. Alternatively, grid lines may be identified by only the principal digits as seen in lines 96 and line 94 aslong as at least one full set of UTM grid values are provided. (See Figure 7 for additional details.).
29594
4292000mN
4293
94
96 297000mE
USNG Principal Digits
472
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
26
Figure 7. Convention for portrayal of grid lines, UTM values, and single USNG 100,000-meter Square Identification
1,000 meter US National GridNorth American Datum 1983Grid Zone Designation: 18S100,000-m Square Identification: UH
312 313 314 315000mE
92
4293
4294
95
4294
313
4293
95
12 314 315
4292000mN
Grid Zone Designation18S
UH
100,000-m Square ID
U.S. National Grid
473
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
27
298 299 300 301000mE
98
4299
4300
01
TH UH
UHTH
TJ UJ4300
299
4298000mN
4299
01
98 300 301
UH
UJ
UJTJ
TJ
TH
Figure 8. Convention for portrayal of grid lines, UTM values, and multiple USNG 100,000-meter Square Identifications
Grid Zone Designation18S
3 00
43 00
TH
TJ
UH
UJ
100,000-m Square ID
U.S. National Grid
1,000 meter US National GridNorth American Datum 1983Grid Zone Designation: 18S100,000-m Squares: TH, UH, TJ, UJ
474
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
28
C.1.7.2 Read right and up 475
476
The numerical part of a grid reference always contains an even number of digits. The first half of 477
the total number of digits represents the Easting, and the second half the Northing. The standard 478
convention of reading "right (Easting) and up (Northing)" is employed. 479
480
C.1.7.3 Read right 481
482
To read the Easting coordinate, locate the first Easting (vertical grid line to the left of the point of 483
reference and read the large digits, the principal digits labeling the line either in the top or bottom 484
margin or on the line itself. Smaller digits shown as part of a grid number are ignored. Estimate, 485
or scale the distance between the Easting line to the left of the point and the point itself. 486
487
C.1.7.4 Read up 488
489
The reading of the Northing coordinate is made in a similar manner. Locate the first Northing 490
(horizontal) grid line below the point of reference and read the principal digits labeling the line 491
located in the left or right margin or on the line itself. Then estimate, or scale the distance between 492
the Northing grid line below the point and the point itself. 493
494
C.1.7.5 Grid coordinates 495
496
The numerical part of a point reference taken from a 1,000-meter grid (on maps at scales of 497
1:100,000 and larger) is typically either a six-digit or eight-digit number; for example 234064 or 498
23480647. For a six-digit grid coordinate (i.e. 234064), reading from left to right, the 23 499
represents the 10,000 and 1,000 digits of the first Easting grid line to the left of the point, the 4 500
represents the estimated or scaled (nearest 100 meters) from the Easting line to the point, the 06 501
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
29
represents the 10,000 and 1,000 digits of the first Northing grid line below the point, and the 4 502
represents the estimated or scaled (nearest 100 meters) from the Northing grid line to the point. 503
504
C.1.7.6 Example reading of grid coordinates 505
506
Refer to Figure 9 (pg. 31) for the following example. 507
A USNG reference is formally written as an entity without spaces, parentheses, dashes, or decimal 508
points. In this example the grid coordinates are shown for a map feature, a small cemetery. From 509
the legend the feature is located in GZD (18S) and 100,000-meter square (TH). For the grid 510
coordinates, read right to the grid intersection immediately left of the place of interest. In Figure 9, 511
it is line 95. Then identify the grid line below the point (in this example 92). The coordinate value 512
9592 gives the location to within 1,000 meters. Measuring or estimating right in meters from line 513
95, finds the cemetery is another 415 meters. The complete USNG Easting component is 95415. 514
Measuring up (north) from line 92, the cemetery is another 635 meters. The complete USNG 515
Northing component is 92635. In this example a precision of 10 meters is required, thus the eight-516
digit coordinate value of the cemetery is 95419263. Notice how the 1-meter values of 5 have been 517
dropped in the eight-digit grid coordinates. The USNG coordinate values are: 518
519
Full USNG: 18STH95419263
Without GZD: TH95419263
Without GZD and 100,000-meter Square Identification: 95419263
520
521
Using the example of the cemetery above, grid coordinates are illustrated below for four, six, eight, 522
and ten digits. These values represent a point position (the southwest corner) for an area of 523
refinement. 524
525
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
30
Four digits 9592 Locating a point within a 1,000-meter square. 526
Six digits 954926 Locating a point within a 100-meter square. 527
Eight digits 95419263 Locating a point within a 10-meter square. 528
Ten digits 9541592635 Locating a point within a 1-meter square. 529
530
Federal Geographic Data Committee XXX United States National Grid Annex C – USNG Implementations
31
This figure illustrates how to obtain the spatial address for a feature on the map, in this case a cemetery. Coordinates are depicted as full and truncated values. Values preceding grid coordinates are the Grid Zone Designation, and 100,000-meter Square Identification (In this case 18S and TH respectively). These values are found in the Grid Reference Box in the map legend and are used as appropriate to locate the feature within increasingly larger areas. A full coordinate (i.e. 18STH95419263) provides a unique value over the entire world. TH95419263 provides a value with 10-meters precision out of a large, regional size area.
Finding 95419263. Think 9541 / 9263. - Reading right to grid line 95, measure right another 410-meters. Dropping the one-meter digit 0 produces the grid coordinate Easting value 9541. - Read up to grid line 92. Measure up another 630-meters. The Northing coordinate value is produced from grid line 92 + 630-meters (drop the 0) to make 9263. This makes the grid coordinate 95419263 (think 9541 / 9263).
Truncated examples:Feature: USNG Grid Coordinates:Bench Mark 324 94349341Pond 94329206Building 95649379Road intersection 96189260
Map extract from US Geological Survey7.5-minute quadrangle FAIRFAX, VA, 1994 edition.
Grid: 9592
410-meters
630-meters
Grid: 18STH954159263518STH95419263
TH9541926395419263
954926
Figure 9. How to read United States National Grid (USNG) grid coordinates.
4294
Grid Zone Designation18S
3 00
43 00
TH
TJ
UH
UJ
100,000-m Square ID
U.S. National Grid
531
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
32
532
533
534
535
536
United States National Grid 537
Annex D (Informative) 538
General Conventions for the USNG539
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
33
ANNEX D (Informative) 540
General Conventions for the USNG. 541
542
D.1 Appropriate use of truncated values 543
544
Full USNG values should be provided when they are used to indicate a geoaddress on stationary 545
letterhead, business cards, etc., even though the reader will know from the street address that it is 546
in the vicinity of a given town. This will facilitate someone using USNG geoaddresses with a GPS 547
receiver or digital map. For example: 548
549
Department of Interior 550
1849 C Street NW, Washington, DC 20006 551
USNG: 18SUJ22850705 552
553
Alternatively, when two people are exchanging positioning information by voice or other informal 554
means, they will often use only the USNG grid coordinate, such as: "We're located in Washington 555
at 1849 C Street, NW, grid 22850705." 556
557
A USNG spatial reference is formally written for general applications as an entity without spaces, 558
parentheses, dashes, or decimal points as depicted above. If users must break a spatial reference 559
into segments to facilitate reading, the following convention shall be used. 560
561 18S UJ 228070 562
or 563 18S UJ 2286 0705 564
565 This convention is most appropriate in hand written notes or GPS receiver equipment displays. 566
567
568
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
34
D.2 Geographic indexing 568
569
D.2.1 National Atlas or Map 570
571
Features should be referenced in a map or atlas index using truncated USNG values because such 572
an index can then be used with any map conforming to this standard thus promoting 573
interoperability and the sharing of index information. In the case of an atlas, the particular page 574
numbers would also be indicated. For example, the cities of Huntsville can be referenced as: 575
576
Huntsville, AL ED 3743 577
Huntsville, AR VV 3393 578
Huntsville, MO WD 3965 579
Huntsville, OH KE 6280 580
Huntsville, TN GF 2532 581
Huntsville, TX TQ 5501 582
Huntsville, UT VL 3567 583
584
The exception to this format is Alaska, which exceeds 18° of latitude and longitude in extent (more 585
than three grid zones). For Alaska, the GZD should also be shown. 586
587
D.2.2 State map index 588
589
An index for a state atlas or map for Texas can reference cities as: 590
591
Huntington UQ 4961 592
Huntoon LF 5335 593
Huntsville TQ 5501 594
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
35
Huntsville St Park TP 5790 595
Hurlwood GT 7419 596
597
In the case of a state atlas, the page numbers for each feature would also be indicated. The 598
exception to this format is again Alaska, where the GZD should also be shown. 599
600
D.2.3 City street index 601
602
A large-scale atlas or street map for Huntsville, TX can index street names as: 603
604
Baker TP 562995 605
Beto TP 571981 606
Bowers TQ 570005 607
Brook TP 567984 608
Bush TQ 543021 609
610
The coordinate values would usually be for the place where the street name appears on the map. 611
Note that since the extent of Huntsville, TX is not larger than 100 x 100 kilometers, the 100,000-612
meter Square Identifications are not essential in this street index. A city street atlas would also 613
reference the page number unique to that atlas for the street. 614
615
D.3 Portrayal of USNG grids and grid values on maps 616
617
D.3.1 Grid spacing 618
619
On large-scale paper maps, precise measurement requires a fine line square grid. Grids provide 620
the user with a geodetic reference in close proximity to any point on the map facilitating 621
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
36
measurement and compensating for paper distortion. The size of grid squares is a trade off 622
between a precise reference and map clutter. Table 2 provides a proven and useful convention and 623
guide where grid squares on maps are no smaller than 20mm nor larger than 100mm along each 624
side. 625
Table 2. Grid spacing recommendation 626
627
Map scale Grid spacing
(On ground in meters.)
Grid spacing
(On map in millimeters.)
1:10,000 1,000 100
1:20,000 1,000 50.0
1:24,000 1,000 41.6
1:25,000 1,000 40.0
1:50,000 1,000
or
5,000
20
or
100.0
1:62,500 5,000 80.0
1:63,360 5,000 78.7
1:100,000 10,000 100.0
1:250,000 10,000 40.0
1:500,000 50,000 100.0
1:1,000,000 100,000 100.0
628
629
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
37
D.3.2 Grid value portrayal 629
630
The USNG is based on the UTM grid, and as such the first two digits in USNG Easting and 631
Northing are the same as the 10,000-meter and 1,000-meter digits of UTM Easting and Northing 632
coordinates. Provisions should be made so map users can have essential information for 633
identifying the UTM coordinate equivalent of each USNG coordinate. A sample of at least one 634
full UTM value should be shown for both an Easting and Northing values, preferably in the lower 635
right corner of the map. When UTM values are shown, the principal digits are provided in larger 636
type. Other grid lines should be identified using UTM principal digits (both the 10,000-meter and 637
1,000-meter UTM values) with the proceeding digits as superscript. Alternatively, only the 638
principal digits for grid lines need be shown, but a sample full UTM value for both the Easting and 639
Northing axis must be depicted at least once on the map. Annex C, Figure 6, 7, and 8 (pgs. 25 – 640
27) depicts how grid lines are labeled and 100,000-meter squares identified on the map and along 641
the neatline. 642
643
D.3.3 Grid reference box 644
645
Maps at scales 1:500,000 and larger should provide a grid reference box with the content 646
illustrated in either Figure 4 or 5 (Annex C, pgs. 22 and 23) and similarly configured. 647
648
D.3.4 Map legend information. 649
650
Map legends should contain the following information regarding the grid; 651
- Size of grid squares and identify grid as US National Grid 652
- Datum to which grid is referenced. 653
- Grid Zone Designation data. 654
- 100,000-meter Square Identification data. 655
Federal Geographic Data Committee XXX United States National Grid Annex D – General Conventions for the USNG
38
656
Example for maps contained within a single 100,000-meter square: 657
658
1,000-meter grid, US National Grid 659
North American Datum 1983 660
Grid Zone Designation: 18S 661
100,000-m Square Identification: UH 662
663
Example for maps that cover two or more 100,000-m squares: 664
665
1,000-meter grid, US National Grid 666
North American Datum 1983 667
Grid Zone Designation: 18S 668
100,000-m Squares: TH, UH, TJ, UJ 669
Federal Geographic Data Committee XXX United States National Grid Annex E – USNG Standardized Numbering for NAD 27 Maps
39
670
671
672
673
674
675
United States National Grid 676
Annex E (Informative) 677
USNG Standardized Numbering for NAD 27 678
Federal Geographic Data Committee XXX United States National Grid Annex E – USNG Standardized Numbering for NAD 27 Maps
40
ANNEX E 679
USNG Standardized Numbering for NAD 27 Maps 680
681
Since the adoption of the NAD 83 as the U.S. national datum, there has been a sustained effort by federal 682
government mapping agencies to change national maps from the NAD 27 to the NAD 83 datum. However, 683
a substantial percentage of maps over the U.S. remain on the NAD 27 datum and that situation may 684
continue for some time. 685
686 The U.S. National Grid (USNG) numbering scheme for the 100,000-meter squares, is identical to the 687
Military Grid Reference System (MGRS) scheme for 100,000-meter squares designed for use with the WGS 688
84 over U.S. areas. This same numbering scheme shall also be used with the NAD 27 on the Clarke 1866 689
ellipsoid for the USNG. 690
691 By use of one single scheme (Figure 3 – pg. 11), the Grid Zone Designation and 100,000-meter Square 692
Identification will be the same for NAD 83 and NAD 27 datums. The ONLY difference will be in the two 693
UTM coordinates, which will be based on the geodetic coordinates as defined on their respective datums. 694
695 For example, the scheme for two adjacent 1: 24,000-scale quads within the same 100,000 meter square, 696
e.g., FALLS CHURCH, VA-MD (NAD 83) and WASHINGTON DC WEST, DC-MD-VA (NAD 27), 697
would portray the same 100,000-meter Square Identifications "UJ". The ONLY difference will be in the 698
datum based UTM coordinates. 699
700 Example - The Washington Monument (USNG): 701
18S UJ 2348 0647 [NAD 83 is implied] 702
18S UJ 2345 0626 (NAD 27) 703
704
705
Federal Geographic Data Committee XXX United States National Grid Annex F - Glossary
41
705
706
707
708
709
710
711
712
713
United States National Grid 714
Annex F (Informative) 715
Glossary716
Federal Geographic Data Committee XXX United States National Grid Annex F - Glossary
42
ANNEX F (Informative) 717
Glossary 718
719
ANSI American National Standards Institute 720
FGDC Federal Geographic Data Committee 721
GIS Geographic Information System 722
GPS Global Positioning System 723
GZD Grid Zone Designation 724
DMA Defense Mapping Agency 725
ISO International Organization for Standardization 726
MGRS Military Grid Reference System 727
NAD 27 North American Datum 1927 728
NAD 83 North American Datum 1983 729
NSDI National Spatial Data Infrastructure 730
NIMA National Imagery and Mapping Agency 731
PLSS Public Land Survey System 732
SPCS State Plane Coordinate System 733
UGRS Universal Grid Reference System 734
USNG United States National Grid 735
UTM Universal Transverse Mercator 736
WGS 84 World Geodetic System 1984 737