1、 MIL-PRF-89023 9999906 20bLbL L7T W I METRIC 1 MIL-PRF-89023 19 December 1997 PEREQRMANCE SPECIFICATION DIGITAL NATICAL CHART This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope This specification defines the content and format for
2、the The DNC is a vector-based digital product that portrays selected U.S. National Imagery and Mapping Agency (NIMA) Digital Nautical Chart (DNC) product. maritime significant physical features in a format suitable for computerized marine navigation. 1.2 Purpose The DNC is a general purpose global d
3、atabase designed to support marine navigation and Geographic Information System (GIS) applications. This specification provides a description of the content, accuracy, data format, and design of the DNC database. 1.3 Classification. DNC data is classified into four basic types, corresponding to DNC
4、libraries, based on the scale of the source charts. These are HARBOR, APPROACH, COASTAL and GENERAL. A BROWSE library is also included, which provides a global overview of the DNC coverage. 2. APPLICABLE DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3 and 4 of
5、 this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to ensure the completeness of this list, document users are cautioned that they must meet all specifie
6、d requirements documents cited in sections 3 and 4 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following specifications, standards, and,handbooks form a part of this document to the Beneficial comments (recommen
7、dations, additions, deletions) and any pertinent data which may be of we in improving this document should be addressed to : Director, National Imagery-and Mapping Agency, ATTN: Customer Support/COD, Mail Stop P-38, 12310 Sunrise Valley Drave, Reston, VA 20191-3449 by using the Standardization Docum
8、ent Improvement Proposal (DD Form 1426) appearing at the end of this document or by letter. AMSC NIA AREA MCGT DISTRIBUTION STATEt4ENT A. Approved for public release; distribution is unlimited. Licensed by Information Handling Services Licensed by Information Handling ServicesMIL-PRF-89023 9999906 2
9、063762 O06 * c MIL-PRF-89023 extent specified herein. Unless otherwise specified, the issues of these documents are those listed in the current Department of Defense Index of Specifications and Standards (DODISS) and the supplement thereto, cited in a solicitation. S PECI FICAT ION S DEPARTMENT OF D
10、EFENSE MIL-H-89201A Military Specifications for digital products, such as DNC, accuracy is expressed in ground distances. The following shows the ground distance horizontal accuracy categories for DNC product resolutibns. Accuracy categories are not listed for DNC GENERAL charts because these are co
11、mpiled from sources of 1:500,000 and smaller. exceed 500m in all cases. for an indication of source chart scale. Feature accuracy of DNC GENERAL charts should be considered to The user should refer to the Data Quality coverage 3 Licensed by Information Handling Services Licensed by Information Handl
12、ing ServicesMIL-PRF-89023 m 9999906 20619611 989 m Class 1 2 5m 2 5 Om 3 100m 4 loom MIL- PRF- 8 9 O 2 3 DNC CE APPROACH 5 Om . 250m 100m 500m 200m 1000m 2 O Om 1000m 500m 3.2.2 Absolute vertical accuracy. The difference between an assigned elevation and the true elevation at a specific point. In th
13、is comparison, both elevations must be referenced to MSL. A points elevation may be determined through interpolation of the digital contour file or it may be listed as a vertex coordinate of a feature. Vertical accuracy is expressed at 90% probability (.9p) linear error as a proportion of the contou
14、r interval. The following lists the vertical accuracy categories: Class DNC LE (Contour Interval) 0.5 1.0 2.0 2.0 3.2.3 Relative accuracy. NIMA does not have a formal relative accuracy objective for this product. 3.2.4 Hydrographic accuracy. NIMA strives to compile hardcopy nautical charts with the
15、most accurate depth information available. compiled from a variety of sources with varying accuracies. The most accurate data is taken from hydrographic surveys which meet IHO survey vertical accuracy standards. Information regarding the source data used for each chart comprising the DNC can be foun
16、d in the Data Quality coverage of each library. 3.3 Datum. 3.3.1 Horizontal datum. The horizontal datum shall be referenced to The charts are WGS84. will be converted from their original horizontal datum to WGS84. If the source map/chart sheets are not referenced to WGS84, then they 3.3.2 Vertical d
17、atum. Charts generally have three vertical datums. Topographic features are referenced to Mean Sea Level. Shoreline is referenced to Mean High Water. The hydrographic features are referenced to a vertical datum based on low water tide level and is called the Sounding Datum or Hydrographic Datum. The
18、 specific low water datum used depends on the type of tide in the area or on the number and magnitude of high and low tides in one tidal cycle. Hydrographic datums used in the DNC will be specified in the Data Quality coverage for each library. 3.4 Units of measure. Units of measurement in this spec
19、ification are generally given in the metric system. With very few exceptions, units of measurement for the DNC will employ the metric system (see Appendix section A.3.1.2). 3.5 DNC product description. This section provides information about the DNC databases. 3.5.1 Database sources. The DNC is base
20、d on the feature content of the hardcopy Harbor, Approach, Coastal and General charts produced by NIMA. 4 Licensed by Information Handling Services Licensed by Information Handling Services MIL-PRF-89023 m 9999Ob 20bLb5 815 m BROWSE library thematic layers MIL-PRF-.8 9023 Coverage name 3.5.2 DNC dat
21、abase design. This specification contains the database design and the feature content for a thematically layered, relationally structured set of databases to support electronic chart display systems. layers. APPROACH, and COASTAL and GENERAL libraries each contain twelve thematic layers. The BROWSE
22、library contains two thematic layers (TABLE 1). 3.5.3 Thematic layer organization. The DNC is organized into thematic Each thematic layer is stored as a single coverage. The HARBOR, Coastline/Countries Library Boundaries TABLE 1. Thematic layers for GENERAL, HARBOR, APPROACH, COASTAL and BROWSE COA
23、LIB libraries. GENERAL, HARBOR, APPROACH, and COASTAL library thematic layers Cultural Landmarks Earth Cover Environment Hydrography Inland Waterways Land Cover Limits Aids to Navigation Obstructions Port Facilities Relief Data Quality Coverage name CUL ECR ENV HYD IWY LCR LIM NAV OBS POR REL DQY 3.
24、5.4 DNC feature coding scheme. Attribute Coding Catalog (FACC), developed by the Digital Geographic The DNC utilizes the Feature and Information Working Group (DGIWG) to support- the Digital Geogiaphic Information Exchange Standard (DIGEST). 3.5.5 Coordinate system. DNC data is stored in decimal deg
25、rees as geographic coordinates with southern and western hemispheres having a negative sign for latitude and longitude, respectively. The horizontal resolution for the geographic coordinates should be stored to the equivalent precision of 0.02 arc-seconds (0.000005 decimal degrees) for the GENERAL a
26、nd COASTAL libraries, and 0.01 arc-seconds (0.000003 decimal degrees) for the APPROACH and HARBOR libraries. 3.5.6 DNC tiling scheme. Each non-BROWSE DNC coverage is divided into a seamless set of tiles using the World Geographic Reference System (GEOREF) described in DMA TM 8358.1. quadrangles, the
27、 sides of which are specific arc lengths of longitude and latitude; each quadrangle is identified by a simple systematic letter code giving positive identification with no risk of ambiguity. This system divides the surface of the earth into a. DNC tile sizes. The DNC is divided into libraries based
28、on the source chart scale. Since traditional hardcopy nautical charts are not produced in standard sizes or scales, the DNC groups paper chart sizes into four scale bands (see TABLE 2) and uses an equal arc-length (measured in degrees of latitude/longitude) tiling scheme with the tile sizes shown. l
29、ower left (southwesternmost) corner of each tile is identified using the GEOREF naming conventions described in 3.5.5.b. This GEOREF identifier is used as the name for the directory containing the primitives contained in that tile. There is no conflict in tile names since the tiles for each chart sc
30、ale band reside in different libraries and are therefore uniquely identified by The 5 Licensed by Information Handling Services Licensed by Information Handling ServicesMIL-PRF-9023 = 999990b 2061ibb 751 I MIL-PRF-89023 their pathnames (DNC03GEN03MK“ is a 3“ tile in the GENERAL library and DNC03COA0
31、3MK“ is a 3 tile in the COASTAL library of the DNC03 database). TABLE 2. DNC tile sizes. COASTAL b. GEOREF description. There are 24 longitudinal zones each of 15 degrees width extending eastward from the 180 meridian around the globe through 360 degrees of longitude. These zones are lettered from A
32、 to 2 inclusive (omitting I and O). There are 12 bands of latitude each of 15 degrees height, extending northward from the South Pole. These bands are lettered from A to M inclusive (omitting I) northward from the South Pole. This code divides the earths surface into 288 15-degree quadrangles, each
33、of which is identified by two letters. zone and the second letter that of the latitude band. quadrangle is sub-divided into 15 one-degree bands of longitude eastward from the western meridian of the quadrangle. These one-degree units are lettered from A to Q inclusive (omitting I and O). Each 15-deg
34、ree quadrangle is also sub-divided into 15 one-degree bands of latitude northward from the southern parallel of the quadrangle. These bands are lettered from A to Q inclusive (omitting I and O). See FIGURE 1. The first letter is that of the longitude Each 15-degree K 1“ x 1 TILE MKNQ Q P N M L K J H
35、 6 F E 0 C B A 15“ x 15“ ABCDEFGHJKLMNPQ M GEOREF 15 x 15 OFFSET = MK 15 W. Longitude, 45 N. Latitude FIGURE 1. 1 by 1 GEOREF tiling scheme example. For the GENERAL and COASTAL libraries, each 15-degree quadrangle is sub- divided into five three-degree bands of longitude eastward from the western me
36、ridian, and five three-degree bands of latitude northward from the southern 6 Licensed by Information Handling Services Licensed by Information Handling ServicesMIL-PRF-89023 W 9999906 20bL9b7 b8 1 4 MIL-PRF-89023 parallel of the quadrangle. The resulting 25 three-degree zones are coded as shown in
37、FIGURE 2. Thus, a four letter code can be used to represent any tile in the GENERAL or COASTAL libraries. K 3 x 3 TILE MK“ 15 x 15 GEOREF i0 x 15 OFFSET = 15 W. Longitude, 45 N. Latitude MK FIGURE 2. 3“ by 3“ tiling scheme example from the GEOREF off set “MK“ . 30 x 30 TILE ldwQ3030 O000 3000 GEOmF
38、1- x 1 OEFSET = MI(NQ FIGURE 3. 30 by 30 tiling scheme example from the GEOREF offset “MKNQ“ GEOREF specifies that cells of smaller than lo (but greater than 1) are to be identified by the location of the southwest corner of the cell in minutes, using the southwest corner of the lo cell. Thus, tiles in the APPROACH and HARBOR libraries are named as illustrated in FIGURE 3 and FIGURE 4, respectively. characters. Note that names for tiles in these libraries require 8 7 Licensed by Information Handling Services Licensed by Information Handling Services
