MAPS and CHARTS
Next part of this discussion will center on maps and charts. Besides the USCGS/NOAA products, the military and a number of private companies are also sources.
The U.S. Army Air Corps also produced maps of the US that showed where airfields were. The ones I have scene so far as interesting, but not good enough to obtain good coordinates of an airfield's location. The earliest one I have is a January 1920 "Aerial Map of the United States" and depicts Government Aerodromes, Post Office Fields (Intermediates), Emergency fields, Municipal Fields, U.S.A. Signal Corps Meteorological Stations, U.S. Weather Bureau Meteorological Stations and Boundaries of Aviation Forecast Zones. It also depicts lines of magnetic deviation. Given it was dated January 1920, the data must have been accumulated in 1919. The Army continued to print maps for aerial usage and the Dept. of Defense continues to do so even today.
The USCGS / NOAA / FAA are all parts of the Dept. of Commerce in the Government. Formal aeronautical charts started about 1930. Some of the early types produced were referred to as United States Airway Maps. These have most of the characteristics of the Sectional Aeronautical Chart. The name was changed over to the familiar Sectional Aeronautical Chart by the mid 1930s. Night Flying Charts were also produced for a limited time in the early to mid 1930s. Regional Aeronautical Charts were also produced, some starting in the mid 1930s. The base for aeronautical charts is the topographic map of 1:250,000 scale.
The USA Military also produce a wide range of aeronautical, topographic and specialized maps. The US Army produced aerial maps from about 1915. Many of these maps were later turned over to the USCGS. The military mapping system was consolidated after World War II and became the Defense Mapping Agency. The consolidation brought the mapping services from the Army, Navy and USAF under one organization. For the period from about 1946 to 1970, the DMA produced maps under the "USAF" designation that were the same, for the most part, as the USCGS SAC and WAC charts. The DMA produced a number of specialized charts for approaches, targeting, radar reflectivity and other things I am still learning about. I have tried to find a listing of all types that the DMA has produced, but so far, no luck. The US Army also produces (under DMA) maps referred to as Joint Operation Graphic (Air) what are excellent maps but are not readily available. Sometimes they show up on Ebay, but nothing consistent. Some aeronautical maps I have found out about include:
1). Special Aeronautical Chart; 2). USAF Training Route Chart; 3). Jet Navigation Chart; 4). Radar Chart; 5). Special World Aeronautical Chart; 6). Approach Chart; 7). USAF Operational Navigation Chart (these ONC charts are generally the same as WACs in terms of coverage and chart number. The cartography is different.); and 8). Target Complex Chart - Series 250. I am sure there are many others that I am unaware of yet.
Road maps supplied by the oil/gasoline service stations sometimes include some airfields. Generally these are not very accurate and only use a symbol for an airfield. Sometimes the city maps could depict an airfield fairly accurately as to its location. Most city maps do not cover a large area and airfields would, by the nature, often be outside of town and not covered. You can find these on Ebay easily. Trying to get specific time frames and areas is up to your own diligence in scanning Ebay for them.
State and county maps can be used too. Depending upon the state, county maps were produced principally for two purposes. To establish the county and for survey of land plots, roads and key terrain features. There are so many counties that it is to great of a problem for an individual to have very many.
Many states also produce there own "state" aeronautical chart. These state charts generally use either 1:500,000 or 1:1,000,000 scales. They tend to use the same symbols as the USCGS/NOAA/FAA charts. They are mainly produced by companies specializing in making aeronautical charts.
Searching charts is a time consuming process, but necessary if you are looking for airfields. Depending upon how experienced you are and you will need to find out what techniques work for you. Charts can come in all types and quality. To me, the SAC is preferred as the scale is 1:500,000, making it easer to find and locate airfields. When you acquire (buy or get someway or another) old charts, they can been in excellent/mint condition or they can be heavily soiled and written on and deteriorating. After all, to the majority of pilots and navigators (or other users of these charts), they were throw a ways. Who would keep them? When they were obsolete, you were encouraged to get rid of them. Fortunately, some folks were pack rats and kept them. A good source is Ebay for charts. Sometimes, sellers ask way too much for old charts. I have scene the average price go from around $2.00 for a good condition chart to now over $10.00.
There is a web site that has some of the older aeronautical charts online. This is the "Historical Map & Chart Project" located on a NOAA Government web server. You can find some old and specialized charts there. Select "aeronautical" under the "select the type" and click on search. It will provide everything they have. You can view the charts online or you can down load them. You will need to download the Mr.SID software to view the charts on your own computer. Might notice the files are large. Anywhere from 0.5MB to 10MB. If you have broadband or DSL, you are OK as they download quickly.
The USCGS produces the standard series of topographic maps. The topographic maps are not updated very often. Some can go as much as 30 years between updates. There are a number of sources on the Internet for getting to online topographic maps. Terraserver is one I mentioned above. Topographic maps start at the 1:24,000 scale and are referred to as the Topographic Quadrangle Map. The intermediate scale maps are at 1:50,000 and 1:100,000 scales. There are some that use the 1:62,500 scale. The small scale maps series use 1:250,000 and 1:2,000,000.
The best known USCGS maps are those that cover 7.5 minutes of arc, the 1:24,000 scale map. The 1:25,000 scale are based on the metric system (1 centimeter equals 0.25 kilometer). The area covered on a map ranges form 64 square miles at latitude 30 degrees north to 49 miles square at latitude 49 degrees north. The physical size is 22 by 27 inches north of latitude 31 degrees and 23 by 27 inches south of that latitude. You will see that some of these maps use a photographic overlay. These are referred to as Orthophotomaps. These cover the Mexican border and some areas in Minnesota, New Mexico, Nevada and Utah. They also cover some of the area along the Gulf and Atlantic coasts from Texas to Maryland.
The 1:100,000 scale series cover virtually all of the US and represent 30 by 60 minute quadrangle maps. These are derived from the 1:24,000 scale maps but show distances and contour internals in meters. The measure 24 by 40 inches in size.
County map series are offered with two scale factors. 1:50,000 correspond closely to content found on the 1:24,000 scale quadrangle maps but use meters for contours. The 1:100,000 have less detail and measure 38 by 49 inches in size. Approximately 20 percent of the USA's counties are covered (10% at 1:50,000 and 10% at 1:100,000 scales.) These are based on the Universal Transverse Mercator projection system.
The 1:250,000 scale series are the base series of maps for aeronautical charts and geologic maps. The quadrangles are 1 degree of latitude by 2 degrees of longitude. A total of 489 of these 1:250,000 maps cover the USA (the 48 contiguous states). Many of these maps go back to the U.S. Army Map Service to the 1950s but all are now maintained by the USCGS.
The US Army produced many of the USCGS topographic maps of the United States. I personally have a number of topographic maps covering parts of Arizona in the 1940s and 1950s that were made by the US Army. They are done to the same coverage and standards as used by the USCGS. I assume that the US Army had plenty of cartographers and were able to take on the work. It is likely that many of the maps have a history that goes back to when states, particularly in the west, that were not state and the US Army was the only organization producing maps.
There are many commercial sources for maps. The National Geographic Society has produced maps for many many years. Even they show some airports, they are generally not helpful. The best I have found are the DeLorme maps. They produce atlases for each state and these do show many of the small airports and airfields. You can buy a digital version for use on a computer. I have bought some of there material and it is very good - the best I have scene. It is current, so can not be used for finding old airfields that are along gone. The nice thing about it as it can be used for road/street name finding that can help in locating an airfield/airport.
There are many atlases out there. I generally only use an atlas when looking for something in a broad area. I have number of atlases and the best, in my opinion, is the Times of London's Atlas of the World. Greatest cartographic work I have ever scene. I have heard a number of other authorities refer to this as the top atlas produced.