XPLMNavigation

To use:

import xp

The XPLMNavigation APIs give you some access to the navigation databases inside X-Plane. X-Plane stores all navigation information in RAM, so by using these APIs you can gain access to most information without having to go to disk or parse the files yourself.

You can also use this API to program the FMS. You must use the navigation APIs to find the navaids you want to program into the FMS, since the FMS is powered internally by X-Plane’s navigation database.

Navaid Functions

• Iterate through the navaid database:

  • getFirstNavAid(), getNextNavAid()

• Search database based on location, type, partials names:

  • findFirstNavAidOfType(), findLastNavAidOfType()

  • findNavAid()

• Get information about the navaid:

  • getNavAidInfo()

Warning

The values retrieved using these functions generally match the format described in the Navigation Database document (e.g., XP-NAV1150-Spec.pdf) For example, the heading value for Glideslopes is defined as:

Associated localizer bearing in true degrees prefixed by glideslope angle times 100,000. E.g., Glideslope of 3.00 degrees on heading of 122.53125 becomes 300122.53125.

To add to the confusion, whereas the document indicate heights are in feet, it appears the values returned via the API are in meters.

getFirstNavAid()

This returns integer index (navRef) of the very first navaid in the database. Use this to traverse the entire database. Returns NAV_NOT_FOUND if the navaid database is empty.

>>> navRef = xp.getFirstNavAid()
>>> navRef
0

Official SDK XPLMGetFirstNavAid

getNextNavAid(navRef)

Given a navRef, this routine returns the next (navRef). It returns NAV_NOT_FOUND if the navRef passed in was invalid or if was the last one in the database. Use this routine to iterate across all like-typed navaids or the entire database. (Start with getFirstNavAid().)

Note

This merely returns the next navaid in the database. This does not return the next of the same type, or same query (see findFirstNavAidOfType(), or findNavAid()). It is very fast, so one strategy is to enumerate through the full navaid database if you’re trying to do anything complicated (e.g., find all navaids with the same frequency). If you’re looking for all navaids of the same type, you can iterate between getFirstNavAidOfType() and getLastNavAidOfType(): navaids of the same type are guaranteed to be grouped together, though they are not guaranteed to be sequentially continuous.

>>> navRef = xp.getFirstNavAid()
>>> navRef = xp.getNextNavAid(navRef)
>>> navRef
1

Official SDK XPLMGetNextNavAid

findFirstNavAidOfType(navType)

Given a navType (See XPLMNavType below), return the navRef of the first navaid of the given type in the database or NAV_NOT_FOUND if there are no navaids of that type in the database. You must pass exactly one navaid type to this routine.

>>> xp.findFirstNavAidOfType(navType=xp.Nav_DME)
18826
>>> xp.findFirstNavAidOfType(navType=xp.Nav_DME | xp.Nav_VOR)
-1

Official SDK XPLMFindFirstNavAidOfType

findLastNavAidOfType(navType)

Give a navType (See XPLMNavType below), return the navRef of the last navaid of the given type database or NAV_NOT_FOUND if there are no navaids of that type in the database. You must pass exactly one navaid type to this routine.

You’ll note there is no findNextNavAidOfType() function. Because all navaids of the same type are grouped together, you can iterate between findFirstNavAidOfType() and findLastNavAidOfType(). A common work around is to load all navaid information into your plugin and then search within that data structure.

>>> xp.findLastNavAidOfType(navType=xp.Nav_DME)
26189

Official SDK XPLMFindLastNavAidOfType

findNavAid(name=None, navAidID=None, lat=None, lon=None, freq=None, navType=-1)

This routine provides a number of searching capabilities for the navaid database. findNavAid() will search through every navaid whose type is within navType (See XPLMNavType.) Multiple types may be OR’d together, with the default being “any” (matches imply at least one of the OR’d navTypes match not all). findNavAid() returns one navRef based on the following rules:

• If lat and lon are specified, the navaid nearest to that lat/lon will be returned, otherwise the last navaid found will be returned.

• If freq is provided , then any navaids considered must match this frequency. Note that this will screen out radio beacons that do not have frequency data published (like inner markers) but not fixes and airports. Note this is an integer, frequency input is real frequency times 100 to create a integer (e.g., specify 13775 to search for 137.75).

• If name is provided, only navaids that contain the fragment in their name will be returned. (Search is case-sensitive, so “Oakland” will find KOAK, but “OAKLAND” will not.

• If navAidID is provided, only navaids that contain the fragment in their IDs will be returned.

This routine provides a simple way to do a number of useful searches:

Find the nearest navaid on this frequency. Find the nearest airport. Find the VOR whose ID is “KBOS”. Find the nearest airport whose name contains “Chicago”.

>>> xp.findNavAid(name="Chicago", navType=xp.Nav_Airport | xp.Nav_DME)
16813190
>>> xp.findNavAid(name="OAK")
16800138
>>> xp.findNavAid(name="OAK", lat=35, lon=-122)
33705283

Official SDK XPLMFindNavAid

getNavAidInfo(navRef)

See warning about Navaid values above.

This routine returns information about a navaid indicated by its navRef. Fields are filled out with information if it is available. For example, Airports have neither frequency nor heading, so they will always be zero. Fixes (Nav_Fix) do not have height, frequency or heading. There is no way to distinguish between true values of zero and missing values.

Frequencies are in the nav.dat convention as described in the X-Plane nav database FAQ: NDB frequencies are exact, all others are multiplied by 100.

The reg field tells if the navaid is within the local “region” of loaded DSFs. (This information may not be particularly useful to plugins.) (Unlike C API, for python, this parameter is a single byte value 1 for true or 0 for false, not a string.)

Returned value is a NavAidInfo object the attributes

type	XPLMNavType
latitude	float
longitude	float
height	float (in meters)
frequency	int. For NDB, frequency is exact. Otherwise, divide by 100 to get actual.
heading	float
name	str
navAidID	str
reg	int 1= navaid is within the local “region” of loaded DSFs.

Conveniently, it also has a str() representation

>>> navRef = xp.findNavAid(name="OAK", lat=35, lon=-122, navType=xp.Nav_Airport)
>>> navRef
16793550
>>> navInfo = xp.getNavAidInfo(navRef)
>>> navInfo
<xppython3.NavAidInfo object at 0x7f84a16a3220>
>>> navInfo.name
'LIVE OAK CO'
>>> navInfo.navAidID
'8T6'
>>> navInfo.latitude
28.36280
>>> print(navInfo)
LIVE OAK CO (8T6) (28.363, -98.116) ---

Official SDK XPLMGetNavAidInfo

Flight Management Computer

Some aircraft have a Flight Management System which responds to these commands. Some do not. sigh. The Laminar G530 and G1000 work.

Note: the FMS works based on an array of entries. Indices into the array are zero-based. Each entry is a nav-aid plus an altitude. The FMS tracks the currently displayed entry and the entry that it is flying to.

The FMS must be programmed with contiguous entries, so clearing an entry at the end shortens the effective flight plan. There is a max of 100 waypoints in the flight plan.

• Manipulate entry status in FMS

  • countFMSEntries()

  • getDisplayedFMSEntry(), setDisplayedFMSEntry()

  • getDestinationFMSEntry(), setDestinationFMSEntry()

  • getGPSDestinationType(), getGPSDestination()

• Manipulate a particular FMS entry

  • getFMSEntryInfo(), setFMSEntryInfo(), setFMSEntryLatLon()

  • clearFMSEntry()

countFMSEntries()

Returns the number of entries in the FMS.

>>> xp.countFMSEntries()
6

Official SDK XPLMCountFMSEntries

getDisplayedFMSEntry()

Return the index of the entry the pilot is viewing. (For XP 11.55, this appears to always return 0. This has been acknowledged by Laminar Research as bug XPD-11386. The X-Plane 10 737 works correctly, but the 737 which comes with X-Plane 11 does not.

Practically speaking, assume this does not work.

>>> xp.getDisplayedFMSEntry()
0

Official SDK XPLMGetDisplayedFMSEntry

getDestinationFMSEntry()

Return the index of the entry the FMS is flying to. (The “destination” refers to the active leg.) This is an index into the FMS, not into the navaid database.

>>> xp.getDestinationFMSEntry()
0

Official SDK XPLMGetDestinationFMSEntry

setDisplayedFMSEntry(index)

Change which entry the FMS is showing to the integer index specified. (For X-Plane 11.55, this does not appear to do anything. This has been acknowledged by Laminar Research as bug XPD-11386. Like getDisplayedFMSEntry(), this appears to work in X-Plane 11 only for older X-Plane 10 version of the 737 aircraft.)

>>> xp.setDestinationFMSEntry(3)

Official SDK XPLMSetDisplayedFMSEntry

setDestinationFMSEntry(index)

Change which entry the FMS is flying the aircraft toward.

>>> xp.getDestinationFMSEntry()
0
>>> xp.setDestinationFMSEntry(3)
>>> xp.getDestinationFMSEntry()
3

Official SDK XPLMSetDestinationFMSEntry

getFMSEntryInfo(index)

Returns information about the zero-based index entry in the FMS. Value returned is an object (see below).

A reference to a navaid can be returned allowing you to find additional information (such as a frequency, ILS heading, name, etc.). Some information is available immediately. For a lat/lon entry, the lat/lon is returned by this routine but the navaid cannot be looked up (and the reference will be XPLM_NAV_NOT_FOUND.

Note

X-Plane C SDK function takes many parameters, where the data is returned. The XPPython3 function takes a single parameter (Index) and returns all the values in an FMSEntryInfo object.

Object returned by getFMSEntryInfo() containing information about an entry. It has the following attributes:

type	XPLMNavType or XPLM_NAV_NOT_FOUND if this is a lat/lon entry
navAidID	str or None if this is a lat/lon entry
ref	XPLMNavRef or None
altitude	int (in feet)
lat	float latitude
lon	float longitude

Conveniently, it also has a str() representation

>>> info = xp.getFMSEntryInfo(0)
>>> info
<xppython3.FMSEntryInfo object at 0x7ff38c0a5040>
>>> info.navAidID
'LUCOS'
>>> info.ref
337064980
>>> print(info)
Fix: [337064980] LUCOS, (41.638, -70.768) @0'
>>> print(xp.getNavAidInfo(info.ref))
LUCOS (LUCOS) Fix (41.638, -70.768) ---

Official SDK XPLMGetFMSEntryInfo

setFMSEntryInfo(index, navRef, altitude=0)

This routine changes an entry at index in the FMS to have the destination navaid specified by navRef (as returned by findNavAid()) at altitude (in feet) specified. Use this only for airports, fixes, and radio-beacon navaids. Currently for radio beacons, the FMS can only support VORs and NDBs.

Use the setFMSEntryLatLon() fly to a lat/lon.

>>> navRef = xp.findNavAid(navType=xp.Nav_VOR)
>>> xp.setFMSEntryInfo(3, navRef, 1000)
>>> print(xp.getFMSEntryInfo(3))
VOR: [9469] ZDA, (44.095, 15.364) @1000'

Official SDK XPLMSetFMSEntryInfo

setFMSEntryLatLon(index, lat, lon, altitude=0)

This routine changes an entry at index in the FMS to have the destination specified by lat, lon at altitude (in feet) specified.

>>> xp.setFMSEntryLatLon(3, 34, -122.5, 1000)
>>> print(xp.getFMSEntryInfo(3))
LatLon: (34.000, -122.5) @1000'

Official SDK XPLMSetFMSEntryLatLon

clearFMSEntry(index)

Clears the given entry, potentially shortening the flight plan.

Official SDK clearFMSEntry

getGPSDestinationType()

Return the XPLMNavType of the current GPS destination.

>>> xp.getGPSDestinationType()
512

Official SDK XPLMGetGPSDestinationType

getGPSDestination()

Return the XPLMNavRef of current GPS destination.

>>> xp.getGPSDestination()
33706498
>>> print(xp.getNavAidInfo(xp.getGPSDestination()))
LUCOS (LUCOS) Fix (41.638, -70.768) ---

Official SDK XPLMGetGPSDestination

Constants

XPLMNavType

These enumerations define the different types of navaids. They are each defined with a separate bit so that they may be bit-wise added together to form sets of nav-aid types.

Nav_Unknown	=0
Nav_Airport	=1
Nav_NDB	=2
Nav_VOR	=4
Nav_ILS	=8
Nav_Localizer	=16
Nav_GlideSlope	=32
Nav_OuterMarker	=64
Nav_MiddleMarker	=128
Nav_InnerMarker	=256
Nav_Fix	=512
Nav_DME	=1024
Nav_LatLon	=2048

Note

Nav_LatLon is a specific lat-lon coordinate entered into the FMS. It will not exist in the database, and cannot be programmed into the FMS. Querying the FMS for navaids will return it. Use setFMSEntryLatLon() to set a lat/lon waypoint.

Official SDK XPLMNavType

XPLMNavRef

XPLMNavRef is an iterator into the navigation database. The navigation database is essentially an array, but it is not necessarily densely populated. The only assumption you can safely make is that like-typed nav-aids are grouped together.

Use XPLMNavRef to refer to a nav-aid.

XPLM_NAV_NOT_FOUND = -1

XPLM_NAV_NOT_FOUND is returned by functions that return an XPLMNavRef when the iterator must be invalid.

Official SDK XPLMNavRef