1 FGDC Document Number 2 3 NSDI National Spatial Data Infrastructure 4 5 6 United States National Grid 7 (Final Draft) 8 9 10 11 Standards Working Group 12 Federal Geographic Data Committee 13 14 September, 2001 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 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 33 Federal Geographic Data Committee 34 35 Established by Office of Management and Budget Circular A-16, the Federal Geographic Data Committee 36 (FGDC) promotes the coordinated development, use, sharing, and dissemination of geographic data. 37 38 The FGDC is composed of representatives from the Departments of Agriculture, Commerce, Energy, 39 Housing and Urban Development, the Interior, State, and Transportation; the Environmental Protection 40 Agency; the Federal Emergency Management Agency; the Library of Congress; the National Aeronautics 41 and Space Administration; the National Archives and Records Administration; and the Tennessee Valley 42 Authority. Additional Federal agencies participate on FGDC subcommittees and working groups. The 43 Department of the Interior chairs the committee. 44 45 FGDC subcommittees work on issues related to data categories coordinated under the circular. 46 Subcommittees establish and implement standards for data content, quality, and transfer; encourage the 47 exchange of information and the transfer of data; and organize the collection of geographic data to reduce 48 duplication of effort. Working groups are established for issues that transcend data categories. 49 50 For more information about the committee, or to be added to the committee's newsletter mailing list, please 51 contact: 52 53 Federal Geographic Data Committee Secretariat 54 c/o U.S. Geological Survey 55 590 National Center 56 12201 Sunrise Valley Drive 57 Reston, Virginia 22092 58 59 Telephone: (703) 648-5514 60 Facsimile: (703) 648-5755 61 Internet (electronic mail): [email protected] 62 Anonymous FTP: www.fgdc.gov/pub/ 63 home page: www.fgdc.gov 64 65 The following is the recommended bibliographic citation for this publication: 66 67 United States National Grid (USNG), 68 FGDC, September 2001, Reston, Virginia. ii Federal Geographic Data Committee XXX United States National Grid 69 70 CONTENTS 71 Page 72 1. Introduction................................................................................................................................................ 1 73 1.1 Objective.................................................................................................................................... 1 74 1.2 Scope ......................................................................................................................................... 2 75 1.3 Applicability .............................................................................................................................. 2 76 1.4 Related Standards ...................................................................................................................... 4 77 1.5 Standards Development Process................................................................................................ 4 78 1.6 Maintenance Authority .............................................................................................................. 5 79 2. Conformance.............................................................................................................................................. 6 80 3. Main Features and Specifications............................................................................................................... 7 81 3.1 Equivalency with MGRS ........................................................................................................... 7 82 3.2 Basic Numbering ....................................................................................................................... 7 83 3.3 Referencing Scheme .................................................................................................................. 7 84 3.3.1.Grid Zone Designation ............................................................................................. 7 85 3.3.2 100,000-meter Square Identification ........................................................................ 9 86 3.3.3 Grid Coordinates ...................................................................................................... 9 87 4. Relationship to Datums .............................................................................................................................12 88 5. Accuracy and Precision.............................................................................................................................12 89 5.1 Accuracy...................................................................................................................................12 90 5.2 Precision ...................................................................................................................................12 91 5.2.1 Field Applications ...................................................................................................12 92 5.2.2 Special Applications................................................................................................12 93 6. References.................................................................................................................................................14 94 Annex A (Normative) Use of North American Datum 1927 (NAD 27)........................................................15 95 Annex B (Normative) Truncation of UTM Coordinate Values.....................................................................17 96 Annex C (Informative) USNG Implementations...........................................................................................19 97 C.1 Applications .............................................................................................................................20 98 C.1.1 General Features .....................................................................................................20 99 C.1.2 Large Geographic Areas .........................................................................................20 100 C.1.3 Regional Areas........................................................................................................20 101 C.1.4 Local Areas.............................................................................................................21 102 C.1.5 Local Areas Near Grid Zone and/or 100,000-meter Square Boundaries ................21 103 C.1.6 Complete Grid Reference........................................................................................21 104 C.1.7 Reading Grid Coordinates.......................................................................................24 105 Annex D (Informative) General Conventions for USNG..............................................................................32 106 D.1 Appropriate Use of Truncated Values......................................................................................33 107 D.2 Geographic Indexing................................................................................................................34 108 D.2.1 National Atlas or Map ............................................................................................34 109 D.2.2 State Map Index......................................................................................................34 110 D.2.3 City Street Index.....................................................................................................35 111 D.3 Portrayal of USNG Grids and Grid Values on Maps ...............................................................35 112 D.3.1 Grid Spacing...........................................................................................................35 113 D.3.2 Grid Value Portrayal...............................................................................................37 114 D.3.3 Grid Reference Box................................................................................................37 115 D.3.4 Map Legend Information........................................................................................37 116 Annex E (Informative) USNG Standardized Numbering for NAD 27 Maps................................................39 117 Annex F (Informative) Glossary ...................................................................................................................41 118 119 iii Federal Geographic Data Committee XXX United States National Grid 119 Figures 120 Page 121 Figure 1 GZDs of the USNG .......................................................................................................... 8 122 Figure 2 Basic Plan of the 100,000-meter Square Identifications of the USNG............................10 123 Figure 3 Organization of the USNG 100,000-meter squares .........................................................11 124 Figure 4 Methods for showing GZDs and 100,000-meter Squares of the USNG in the 125 Grid Reference Box ........................................................................................................22