A Sectional Aeronautical Chart, often called sectional for short, is designed for navigation under visual flight rules. (In Canada, the equivalent charts used for visual flight are called VFR Navigation Charts (VNCs)).

A sectional chart shows topographical features that are important to pilots, such as terrain elevations, ground features that are recognizable from the airplane cockpit such as rivers, dams, bridges, towers, etc. The chart also shows information on airspace classes, ground-based navigation aids, radio frequencies, longitude and latitude, navigation waypoints and navigation routes.

Sectionals are in 1:500,000 scale and are named for a city on the chart. The charts are updated at six-month intervals. The Federal Aviation Administration (FAA) in the United States publishes over 50 charts covering the continental United States, Alaska, and Hawaii. A more detailed chart is the Terminal Area Charts (TACs) at 1:250,000 scale for the areas around major U.S. airports. The Sectional Chart Legend is the same for both.
AIRSPACE CLASSIFICATIONS
The FAA has designated six classes of airspace, in accordance with International Civil Aviation Organization (ICAO) airspace classifications. Airspace is broadly classified as either controlled or uncontrolled. Airspace designated as Class A, B, C, D, or E is controlled airspace. Class F airspace is not used. Class G airspace is uncontrolled airspace. Controlled airspace means that IFR services are available to aircraft that elect to file IFR flight plans; it does not mean that all flights within the airspace are controlled by ATC. IFR services include ground-to-air radio communications, navigation aids, and air traffic (i.e., separation) services. Aircraft can operate under IFR in uncontrolled airspace; however, the aircraft cannot file an IFR flight plan and IFR services are not necessarily available. Controlled airspace is intended to ensure separation of IFR traffic from other aircraft, both IFR and VFR. The airspace classifications discussed in this section are designed primarily to manage VFR traffic in controlled airspace. The controlled airspace classifications do not affect IFR operations, as IFR traffic is cleared through controlled airspace automatically by ATC. VFR aircraft may operate in Class E controlled airspace without control by ATC, so long as weather conditions permit visual separation of aircraft (during IMC, VFR traffic is prohibited and thereby ensures separation between VFR and IFR traffic). Also, air traffic service is provided to VFR aircraft in Class E airspace only when ATC workload permits. VFR aircraft operating in class B, C, and D airspace must be in contact with ATC; this gives ATC the authority to manage VFR aircraft in the proximity of busy airports. Essentially, the controlled airspace system protects IFR aircraft from VFR aircraft during IMC and in close proximity to busy airports.
In this lesson we will discuss airspace classifications and how to use a sectional chart to determine what airspace you are in when you fly your UAV. There is a link at the end of this lesson for downloading Sectional Aeronautical Charts.
Wow, that's a lot to remember even  if you are piloting a Cessna or Passenger jet. But why does the UAS pilot need to know these things?

As stated in the preface to the lessons, the FAA appears to be generating the UAS pilot examination question pool from the Light Sports pilot question pool.  There will be questions about the National Airspace in the R
emote Pilot Airman Certificate with a Small UAS Rating written examination.
Link to Sectional Aeronautical charts
Click on the image below to download charts from the FAA for the areas you plan to fly your small UAV.

The index of Sectional Charts (shown below) appears on every Sectional Chart. The purple rectangles indicate Terminal Area Charts which are similar to the Sectional charts but double the resolution.
Airspace Classifications and an Introduction to Sectional Aeronautical Charts
Treetop.Academy is operated by MannMade Digital Video (www.mmdv.com)
Treetop.Academy is operated by MannMade Digital Video (www.mmdv.com)
Treetop.Academy is operated by MannMade Digital Video (www.mmdv.com)
Treetop.Academy is operated by MannMade Digital Video (www.mmdv.com)