Resources for Data Designers

Tools

World Editor (WED) is a free, open source tool for airport scenery creation.

The Aviation Formulary is a treasure trove of useful formulae used in aviation, usually explained in easy-to-understand terms.

A good text editor is often useful, to review and search the data files, such as Notepad++ for Windows. Amongst other features, it will convert files between Windows, Mac and Linux formats.

‘Real-world’ aviation data sources

X-Plane relies upon publicly-available, freely-available data sources. We cannot reverse-engineer proprietary databases and use that data. Of course, it is hard to find high-quality, global data that meet these criteria.

There are many sources of ‘real world’ aviation data, and each country often has its own process for maintaining and publishing its data. Some make their data freely available, but others regard this data as a valuable asset to which a high price is associated! Within the USA, data is available by subscription for a nominal fee from the FAA’s National Flight Database (NFD).

Common sources of data are AirNav.com and World Aero Data. The National Aeronautical Charting Office (NACO) gives free access to all US airport and instrument approach charts (other sources offering the same data include AOPA, if you are a member). Many countries offer some kind on on-line access to their aviation data and/or charts – for example, the UK NATS site has detailed colour charts of all UK aerodromes.

Google Earth, Google Maps, Live Search Maps and TerraServer all have a role to play in airport design. Depending upon the imagery available, these tools can provide detailed aerial views of many airports. Ortho-rectification of the images is usually good, but remember to switch off any features that try to show 3D terrain (this can distort the images).

Google Earth can be used to obtain latitude/longitude positions for many features (remember to set the format of the lat/lon to decimal degrees in the Tools/Options menu).
The ‘birds eye’ view on Live Search Maps offers extremely detailed imagery – good enough in many cases so that taxiway signs can be read. But coverage is limited.

‘Real-world’ concepts

The US FAA has published standards for the design of airports:
FAA Aeronautical Information Manual (a very important resource for any aviator).
FAA AC on airport design (a large PDF file).

Magnetic variation: All X-Plane data that contains directional/heading information is defined as a true headings. But published data for localizers almost is always expressed on charts as a magnetic heading, so these need to be converted to a true heading for our data files to ensure correct alignment in X-Plane. But … one ‘gotcha’ is that localizers (and other nav-aids) can be edited within X-Plane itself (on the map screen), and here the bearing is shown as magnetic (on the assumption that users may be trying to build an ILS based upon a real-world chart). The data will be automatically converted to a true heading when X-Plane saves the data.

Global data: X-Plane’s data coverage is global. Different countries often have different standards for the definition and use of their aviation data.

Many pilots who fly only within the USA believe that altimeters should always be switched from a local barometric setting to a standard setting (29.92 inches or 1013 hPa) when climbing through 18,000 feet (the Transition Altitude). But in many countries the TA is much lower, and may even vary within a country (it is usually printed on airport diagrams and approach charts). For example, the TA is at 3,000 feet over much of England, so it is normal for a VFR pilot to cruise at FL40.

The UK and some other countries uses different types of runway markings – these are available in X-Plane, but must be explicitly selected in WED.

Taxiway signs and painted markings are generally consistent around the world, but stylistic difference do exist.

Double check the units of measure: Many countries use a complex mix of metric and imperial units in aviation. The USA generally uses imperial units (but uses the Celsius scale for temperatures). Many other countries use metric units for all measurements, except for elevations (which are – usually – in feet). So, it’s easy to look at an airport diagram and to forget to convert a measurement to the appropriate units for X-Plane. For example, X-Plane now requires all distances (such as displaced thresholds, blastpads) to be defined in metres in its data files, though elevations are still defined in feet.

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