USCGS / NOAA Aeronautical Charts

USCGS and NOAA are the principal sources of maps and charts for gathering information.  USCGS and NOAA are part of the Department of Commerce in the USA's Government.  The USCGS started producing topographic and other charts for the Government back in the 1900s and still produces them.  The aeronautical charts started being produced under the USCGS.  The transfer from USCGS to NOAA (in the early 1970s) was an organizational change and the same people continued to produce the aeronautical products.

The need for specialized maps (hence forth referred to as charts) became evident to support the growth of the aviation and aeronautical needs.  The USA Government was committed to helping to improve safety and growth of aviation in the USA.  The earliest charts produced for the aeronautical market began about 1930. 

The early aeronautical products were referred to as United States Airway Map and consisted of a series that covered the US.  These were the forerunner to the Sectional Aeronautical Chart.  The name was changed over in the mid 1930s to Sectional.  In the mid 1930s, the Regional Aeronautical Chart was introduced.

Various other types were initially produced and by mid 1930s, a standard set of chart types (and other products) were being produced.  These charts were published twice a year (generally) so that they could be relied upon for being up to date.  Airmen were always told to check for latest NOTAMs (Notice to Airmen) for any changes prior to flight.  The principal chart was referred to as a "sectional" aeronautical chart which used a 1:500,000 scale.  To cover the USA, a total of 87 charts were required.  All of the aeronautical charts were produced in color and ranged in cost from $0.25 to $0.40 each in the 1930s.  Today's prices range from around $6.50 to $8.00 depending upon the source where you buy your charts from.

The 1:500,000 scale Sectional Aeronautical Chart (and I will be using "SAC" hence forth) grid remained until the change over to the current system of charts started in 1968 and completed in 1972.  The standard SAC for this period of time measured 42 inches wide by 23.5 inches high.  Virtually identical SAC charts were specially produced by the DMA for the USAF and have a notice on the bottom edge that it is a USAF Edition.  You can also note that there is an overprinted grid that runs "backwards" in degree count down.

The SAC remained pretty much as it was except for some subtle changes.  Up to about 1950, nothing was printed on the back of the SAC.  Starting in 1950, the back of the SAC started to contained information.  The legend was moved there along with a chart (see above) and general flying and navigation information.  In the lower left side of the chart was added an "Aerodrome" list of all fields contained on that SAC.  This has useful information about an airfield, its coordinates, type, runway type and number and general information.  This table remains until the series was discontinued with the "new" SAC.  One small change occurred by the mid 1950s when the town or community associated with the airfield was dropped.

Other subtle changes include a general change in colors during the 1950s followed in the 1960s with another color change.  Overall, the SAC, while covering the same area and using the same identification names, underwent about four evolutions.

By about 1940, a new chart type emerged referred to as the Regional Aeronautical Chart (or RAC) which actually combined various sectional charts into a single chart - side effect it was much larger physically as the scale of 1:500,000 was maintained.  To the best of the data I have, it seems these were stopped after WW2 (after 1945).  These RACs allowed the pilot or navigator to lay out a flight over one chart as opposed to a number of SACs.

In 1945, the USCGS produced a new chart referred to as the World Aeronautical Chart (or WAC) which seems to have replaced the RAC.  The WAC was physically much smaller but covered a larger area than the SAC.  To do this, they scale was changed to 1:1,000,000.  The new chart was 29 inches wide by 22 inches high, easier to use for greater coverage flights.  The WAC continues unto today, but it also underwent a transformation in the 1968-1972 time frame.  More on that later.

WACs covered the entire world (except oceans).  Many of these charts are not produced by the USCGS but rather the Dept. of Defense's Defense Mapping Agency (and its predecessor).  A key difference between DMA charts is the designator "ONC".  A "ONC-470" chart is the same area "470" of a USCGS WAC, but indicates it is Operational Navigation Chart and generally are preceded by "USAF" on them.  I find these ONC WAC charts more difficult to use due to the different colors used, different representation for terrain but mainly the different way that the airfield symbols are depicted.  When that is all you have for a time period for an area, you use it anyway.

Also started after 1945 was a new chart type referred to as the Local Aeronautical Chart (of LAC).  These were restricted to certain areas - large metropolitan city or special areas.  The new chart changed scale to 1:250,000 giving much more detail.  These charts were necessary due to increasing amount of air traffic, especially around large metropolitan areas.  A total of 21 different LACs were produced.  The equivalent of the LAC is still produced referred to as the Terminal Area Control chart (or TAC for short).

In the mid 1960s, the Dept. of Commerce, using the FAA and USCGS, entered into discussions with pilots, navigators, organizations, airlines and the Dept. of Defense on a "new" generation of charts.  The reason was to reduce the overall amount of charts being produced and thus saving money (well, anyway, that was the idea).  Originally, it was proposed to eliminate the WAC entirely but pilots and navigators objected and the WAC was retained a series type.

One of the "odd ball series" is the Flight Chart (or FC).  It is unclear exactly how many of these were produced.  The numbers used due not correspond to a grid layout.  Examples would be FC 185 that covers a swipe from San Antonio, TX to Montgomery, AL.  To the best of my knowledge, these were produced from about 1945 to the early 1950s.

During the 1950s, a replacement series to the FCs came out called the Route Chart (RC).  Approximately 9 of these charts were made for the USA.  They too, dimensionally, were on the same order as the FCs.  Since even more area was covered for the same physical map size, the scale was changed to 1:2,000,000.  Many smaller fields were not longer depicted on this series of charts.  I don't know when they were discontinued, but I have only those printed during the 1950s.

Other "odd balls" include:

1.  Planning charts (two types) - 1:5,000,000 scale and 1:3,000,000 scale

2.  Aircraft Position Charts for the oceans mainly using 1:5,000,000 scale

3.  Jet Navigation Charts - a total of four charts covered the USA and used 1:2,000,000 scale

4.  Instrument Approach and Landing Charts - more than 1100 chart types were produced

5.  Airport Obstruction Plans - these charts used 1:12,000 scale showing objects and hazards in the local area of the airport/airfield.

6.  Radio Facility Charts - two types were produced: 1). used 1:1,500,000 scale; and 2) a 1:3,000,000 scale.

The "new" Sectional Aeronautical Chart (or SAC) encompassed a larger area than the previous SAC.  The scale was retained at 1:500,000 but the size was changed to 59-60 inches wide by 20.6 inches high.  The chart was divided into a "north" and "south" side - thus printed on both sides began.  New colors were used to help understand the terrain and symbols.  The number of SACs printed now became 37 (down from 87).  The new SAC style also implemented a new folding process.  This style is what is currently exists and can be purchased at about any aviation store carrying charts.

The "new" WAC also came out and it too is the same physical size and retains the 1:1,000,000 scale.  Printed on both sides like the SAC.

Specialized charts abound too.  The Dept. of Defense produces all sorts of specialized charts for pilots.  Many of these provide data not typically found on the standard USCGS/NOAA charts.  During the late 1940s and early 1950s, many specialized charts were produced that provided target identification data, radar reflectivity and specialized information.

Now days, current charts can be purchased in traditional paper form, but also electronically on data DVDs.  However, the DVD versions are actually scanned in version of the printed chart (.tiff files and some people sell them as .jpg files).  You can buy subscription services and get updates monthly for the DVD version.  Just to clarify the question before it is asked - the aeronautical products are not copyrighted and are in the public domain.

The map making system is still based, for the most part, on the methods developed many years ago.  Cartographers make maps / charts manually for the most part.  Some elements are electronic now days, but the majority are still produced by manual methods.  Most of the "book" publications are produced electronically.  As each layer is made using the manual process, they are then taken to the large photographic cameras so that the printing can be done by using the offset process.  Most maps are run on four color (yellow, magenta, cyan, black) printing presses.