4.4.6 Airport Obstruction Charts (OC). The OC is a 1:12,000 scale graphic depicting 14 CFR Part 77, Objects Affecting Navigable Airspace surfaces, a representation of objects that penetrate these surfaces, aircraft movement and apron areas, navigational aids, prominent airport buildings, and a selection of roads and other planimetric detail in the airport vicinity. Also included are tabulations of runway and other operational data.
4.4.7 FAA Aeronautical Chart User’s Guide. A booklet designed to be used as a teaching aid and reference document. It describes the substantial amount of information provided on FAA’s aeronauti-cal charts and publications. It includes explanations and illustrations of chart terms and symbols organized by chart type. The users guide is available for free download at the NACO web site.
4.5 Digital Products
4.5.1 The Digital Aeronautical Information CD (DAICD). The DAICD is a combination of the NAVAID Digital Data File, the Digital Chart Supplement, and the Digital Obstacle File on one Compact Disk. These three digital products are no longer sold separately. The files are updated every 56 days and are available by subscription only.
4.5.1.1 The NAVAID Digital Data File. This file contains a current listing of NAVAIDs that are compatible with the National Airspace System. This file contains all NAVAIDs including ILS and its components, in the U.S., Puerto Rico, and the Virgin Islands plus bordering facilities in Canada, Mexico, and the Atlantic and Pacific areas.
4.5.1.2 The Digital Obstacle File. This file de-scribes all obstacles of interest to aviation users in the U.S., with limited coverage of the Pacific, Caribbean, Canada, and Mexico. The obstacles are assigned unique numerical identifiers, accuracy codes, and listed in order of ascending latitude within each state or area.
4.5.1.3 The Digital Aeronautical Chart Supple-ment (DACS). The DACS is specifically designed to provide digital airspace data not otherwise readily available. The supplement includes a Change Notice for IAPFIX.dat at the mid.point between revisions. The Change Notice is available only by free download from the NACO website.
The DACS individual data files are: ENHIGH.DAT: High altitude airways (contermi-nous U.S.)
ENLOW.DAT: Low altitude airways (conterminous
U.S.)
IAPFIX.DAT: Selected instrument approach proce-dure NAVAID and fix data.
MTRFIX.DAT: Military training routes data.
ALHIGH.DAT: Alaska high altitude airways data.
ALLOW.DAT: Alaska low altitude airways data.
PR.DAT: Puerto Rico airways data.
HAWAII.DAT: Hawaii airways data.
BAHAMA.DAT: Bahamas routes data.
OCEANIC.DAT: Oceanic routes data.
STARS.DAT: Standard terminal arrivals data.
DP.DAT: Instrument departure procedures data.
LOPREF.DAT: Preferred low altitude IFR routes
data.
HIPREF.DAT: Preferred high altitude IFR routes
data.
ARF.DAT: Air route radar facilities data.
ASR.DAT: Airport surveillance radar facilities data.

4.5.2 The National Flight Database (NFD) (ARINC 424 [Ver 13 & 15]). The NFD is a basic digital dataset, modeled to an international standard, which can be used as a basis to support GPS navigation. Initial data elements included are: Airport and Helicopter Records, VHF and NDB Navigation aids, en route waypoints and airways. Additional data elements will be added in subsequent releases to include: departure procedures, standard terminal arrivals, and GPS/RNAV instrument approach procedures. The database is updated every 28 days. The data is available by subscription only and is distributed on CD.ROM or by ftp download.
4.5.3 Sectional Raster Aeronautical Charts (SRAC). These digital VFR charts are geo.refer-enced scanned images of FAA sectional charts. Additional digital data may easily be overlaid on the raster image using commonly available Geographic Information System software. Data such as weather, temporary flight restrictions, obstacles, or other geospatial data can be combined with SRAC data to support a variety of needs. Most SRACs are provided in two halves, a north side and a south side. The file resolution is 200 dots per inch and the data is 8.bit color. The data is provided as a GeoTIFF and distributed on DVD.R media. The root mean square error of the transformation will not exceed two pixels. SRACs DVDs are updated every 28 days and are available by subscription only.

FIG GEN 3.2.10
U.S. Terminal Publication Volumes

FIG GEN 3.2.11
Sectional and VFR Terminal Area Charts for Alaska

FIG GEN 3.2.12
World Aeronautical Charts for Alaska

FIG GEN 3.2.13
World Aeronautical Charts for the Conterminous U.S.
Mexico, and the Caribbean Areas

5. National Imagery and Mapping Agency (NIMA) Products
5.1 How to Order NIMA Products. FAA catalog of NIMA Public Sale Aeronautical Charts and Publications (FAA Stock No. DMAACATSET), is available from the FAA NACO Distribution Division. The catalog describes available charts and publications primarily covering areas outside the
　
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