Introduction

Problem Statement

For a long time there has not been a clear and widely established system of categorizing aerodromes. One is necessary, so that international airports and small aerodromes can each be given proper emphasis in the database. This proposal aims to fix this issue.

Proposal

Aerodromes are classified primarily by size/prominence. The following values are available:

A separate tag for seaplane bases is used to as is done with heliports:

Finally secondary tags can be used to add detail and deal with edge cases:

Rationale

Main Tag

Near the beginning of OSM aerodromes were divided into Airports, Aerodromes and Airstrips. This system was lost after an incident, but it still is a natural and useful way to categorize aerodromes, that is, by size or prominence. This then translates to what one can expect to do at the aerodrome, to travel or enjoy leisure.

Previous proposals sometimes mixed in type of use in the main tag which is not ideal, since usage, like general vs. commercial or sports is usually mixed and other tags are better fit for this purpose.

The original system is largely good as is: Airports are bigger and focus more on commercial traffic (travel), Aerodromes are smaller and focus more on general traffic (leisure and airwork) and Airstrips are special in that they have very little infrastructure, can be deployed almost anywhere, and are very numerous.

I however propose adding a bit extra granularity in order to more accurately separate each type of aerodrome and make the system more adaptable. Physical characteristics are described in the Tagging section however here I'll present a statistical analysis.

I have compiled on my page airport statistics from 5 countries comprised mostly of global to regional aerodromes:

As you can see, the division at the top is a very small minority but accounts for the vast majority of passenger traffic in the dataset. Then, we have a division with mostly proportionate statistics which capture a fair percentage of the market. Finally, we have a divsion that represents the vast majority of aerodromes but a very small minority of passengers.

These divsions would correspond to global, continental and regional aerodromes. For the last type, local, we can check the US NPIAS and see that local+basic aerodromes account for 60% of all aerodromes with passenger statistics theoretically even worse than regionals.

Extra Tag

By definition of the ICAO, an aerodrome is anywhere an aircraft can land and take-off. In most cases, this is also the case with the aerodrome=* tag in OSM, irrespective of the types of aircraft that use the aerodrome.

However, precedent has been set by the aeroway=heliport tag, which describes an aerodrome in which only helicopters can land. This makes sense as even though airplanes and helicopters both can use mixed aerodromes, they are always dominated by airplanes since helicopters are an expensive, limited, niche mode of travel. This means that a heliport is very different from a regular aerodrome in termos of its facilities and training and equipment necessary to use it.

The same can be said of seaplanes. The era of seaplanes is long gone since land aerodromes became plentiful after WW2. Now they are limited forms of travel mostly used in undeveloped areas of the world. Seaplane bases also are very different from the average aerodrome requiring special equipment and training. Thus, like heliports, seaplane bases should have their own tag, aeroway=seaplane_base.

The alternatives would be using extra an seaplane=yes tag, which is still inventing new tags, or putting it in the main tag, which makes it more convoluted. Both clash with the existence of the aeroway=heliport tag.

Secondary Tags

Sometimes the most common type of traffic doesn't align with its size, such as with unusually busy general aviation aerodromes and commercial only aerodromes in undeveloped areas. The usage=* tag is used to specify this use.

Private aerodromes can be indicated using the access=* tag. Many times, a private aerodrome is still accessible to the public, even if in limited ways. The many values of the tag give enough way to describe these situations.

In case airsports are practiced at an aerodrome, the leisure=sports_centre + sport=* tags are used. These can happen at a variety of aerodrome sizes and while other traffic is using the aerodrome.

Finally, whether an aerodrome can receive international traffic or not is described by the port_of_entry=* tag. This is normally a legal matter and should be available publicly. It can also be used by other objects like ports or border crossings.

Tagging

Definitions

Main Tag

The following descriptions are based on airport statistics compiled on my page and visual analysis of some of the airports. They are guidelines, not rules.

It should be noted that some airports are cargo transport hubs, sporting dedicated cargo terminals.

If we divide total cargo moved by the standard passenger weight (85kg) we get a very rough figure of extra passenger-equivalents transported. Normally, this doesn't affect an airport's statistics too much but for cargo hubs it can change it by an order of magnitude.

Extra Tag

Secondary Tags

It should be noted that no general aviation airport can be given the tag aerodrome=global. This is because by very nature of general aviation, flights are more focused on their own region or continent at maximum.

We can calculate a passenger equivalent using the average aircraft seats at the airport. The ten busiest general aviation airports in the US have an average aircraft seat number of around 12. If we multiply 12 by low hundreds of thousands, the common aircraft movement number for the top ten, we get a very rough passenger-equivalent in the low millions, making them aerodrome=continental at best.

Examples

Commercial

General

Seaplane

Impacts of Proposal

On Data Consumers

Impact is minimal as the aerodrome=* tag is not altered and aerodrome type values are largely being ignored. aeroway=airstrip is also being largely ignored.

Features/Pages affected

Created

aerodrome=global/continental/regional/local/basic

aeroway=seaplane_base

usage=commercial_aviation/general_aviation

port_of_entry=*

Deprecated

aerodrome:type=* and its values

Current values of aerodrome=*

aeroway=airstrip

Previous Discussions

Wiki

Talk:Aeroways#Airport_Classification

Proposals

Proposal:Airport

Proposal:Aerodrome

Proposal:Key:aerodrome

Proposal:Aerodrome 3

Forum

Doubts with aerodrome tagging

Gap in aerodrome type tagging

Mailing List

Aeroway=Aerodrome Modifier Tags?

Aerodrome types

Aerodrome classification

Draft proposal for Key:aerodrome

Comments

Comment on the discussion page, the forum RFC thread or the mailing list thread.