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{{WIP}}
{{Nasal Navigation|nocat=1}}
{{Nasal Navigation}}
This page contains documentation for the '''<code>geo</code> namespace''' in [[Nasal]]. This namespace provides various geography/position-related [[#Functions|functions]], as well the [[#Coord|main class]]. Everything in the <code>geo</code> namespace is sourced from {{fgdata file|Nasal/geo.nas}}
This page contains documentation for the '''<code>geo</code> namespace''' in [[Nasal]]. This namespace provides various geography/position-related [[#Functions|functions]], as well the [[#Coord|main class]]. Everything in the <code>geo</code> namespace is sourced from {{fgdata file|Nasal/geo.nas}}
{{tip|Copy & paste the examples into your [[Nasal Console]] and execute them to see what they do.|width=70%}}


== Classes ==
== Classes ==
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{{Nasal doc
{{Nasal doc
|mode = class
|mode = class
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = The main class, used widely for storing and managing positional data. Coordinates may be stored in either {{wikipedia|ECEF|Earth-centered, Earth-fixed}} coordinates (x, y and z) or {{wikipedia|geodetic coordinates}} (latitude, longitude, and altitude). In addition, it will convert coordinates as necessary. However, note that for the conversion to work, set_latlon() and set_xyz() must be used.
|text = The main class, used widely for storing and managing positional data. Coordinates may be stored in either {{wikipedia|ECEF|Earth-centered, Earth-fixed}} coordinates (x, y and z) or {{wikipedia|geodetic coordinates}} (latitude, longitude, and altitude). In addition, it will convert coordinates as necessary. However, note that for the conversion to work, set_latlon() and set_xyz() must be used.
}}
}}
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.new([coord]);
|syntax = geo.Coord.new([coord]);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Constructor function. Returns a new <code>geo.Coord</code> instance.
|text = Constructor function. Returns a <code>geo.Coord</code> instance.
|param1 = coord
|param1 = coord
|param1text = An optional <code>geo.Coord</code> instance. If given, the returned instance will contain the values from this argument.
|param1text = An optional <code>geo.Coord</code> instance. If given, the returned instance will contain the values from this argument.
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set(coord);
|syntax = geo.Coord.set(coord);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the coordinates. Returns the <code>geo.Coord</code> instance.
|text = Sets the coordinates. Returns the <code>geo.Coord</code> instance.
|param1 = coord
|param1 = coord
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_lat(lat);
|syntax = geo.Coord.set_lat(lat);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the {{wikipedia|latitude}} coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the {{wikipedia|latitude}} coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = lat
|param1 = lat
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_lon(lon);
|syntax = geo.Coord.set_lon(lon);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the {{wikipedia|longitude}} coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the {{wikipedia|longitude}} coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = lon
|param1 = lon
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_alt(alt);
|syntax = geo.Coord.set_alt(alt);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the {{wikipedia|altitude}} coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the {{wikipedia|altitude}} coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = alt
|param1 = alt
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_latlon(lat, lon[, alt]);
|syntax = geo.Coord.set_latlon(lat, lon[, alt]);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the latitude and longitude coordinates, and optionally the altitude coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the latitude and longitude coordinates, and optionally the altitude coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = lat
|param1 = lat
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_x(x);
|syntax = geo.Coord.set_x(x);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the x-axis coordinate coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the x-axis coordinate coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = x
|param1 = x
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_y(y);
|syntax = geo.Coord.set_y(y);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the y-axis coordinate coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the y-axis coordinate coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = y
|param1 = y
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_z(z);
|syntax = geo.Coord.set_z(z);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets the z-axis coordinate coordinate. Returns the <code>geo.Coord</code> instance.
|text = Sets the y-axis coordinate coordinate. Returns the <code>geo.Coord</code> instance.
|param1 = z
|param1 = z
|param1text = The mandatory z-axis coordinate, in metres.
|param1text = The mandatory z-axis coordinate, in metres.
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coord.dump();
coord.dump();
}}
}}
==== set_xyz() ====
==== set_xyz() ====
{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.set_xyz(x, y, z);
|syntax = geo.Coord.set_xyz(x, y, z);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Sets all three Cartesian coordinates. Returns the <code>geo.Coord</code> instance. All arguments are mandatory.
|text = Sets all three Cartesian coordinates. Returns the <code>geo.Coord</code> instance. All arguments are mandatory.
|param1 = x
|param1 = x
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.lat();
|syntax = geo.Coord.lat();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the latitude coordinate.
|text = Returns the latitude coordinate.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.lon();
|syntax = geo.Coord.lon();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the longitude coordinate.
|text = Returns the longitude coordinate.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.alt();
|syntax = geo.Coord.alt();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the altitude coordinate.
|text = Returns the altitude coordinate.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.latlon();
|syntax = geo.Coord.latlon();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns a vector containing the latitude, longitude, and altitude, in that order.
|text = Returns a vector containing the latitude, longitude, and altitude, in that order.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.x();
|syntax = geo.Coord.x();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the x-axis coordinate.
|text = Returns the x-axis coordinate.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.y();
|syntax = geo.Coord.y();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the y-axis coordinate.
|text = Returns the y-axis coordinate.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.z();
|syntax = geo.Coord.z();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the z-axis coordinate.
|text = Returns the z-axis coordinate.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.xyz();
|syntax = geo.Coord.xyz();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns a vector containing the x, y, and z coordinates, in that order.
|text = Returns a vector containing the x, y, and z coordinates, in that order.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.is_defined();
|syntax = geo.Coord.is_defined();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns 1 (true) if all three coordinates (either x/y/z or /lat/lon/alt) are defined. Note that set_latlon() or set_xyz() must be used for this function to work correctly.
|text = Returns 1 (true) if all three coordinates (either x/y/z or /lat/lon/alt) are defined. Note that set_latlon() or set_xyz() must be used for this function to work correctly.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.dump();
|syntax = geo.Coord.dump();
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Dumps all six coordinates into the console. It requires all three coordinates (either x/y/z or /lat/lon/alt) to be defined. Note that set_latlon() or set_xyz() must be used for this function to work correctly.
|text = Dumps all six coordinates into the console. It requires all three coordinates (either x/y/z or /lat/lon/alt) to be defined. Note that set_latlon() or set_xyz() must be used for this function to work correctly.
|example1 = var coord = geo.Coord.new();
|example1 = var coord = geo.Coord.new();
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.course_to(coord);
|syntax = geo.Coord.course_to(coord);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the initial bearing (see [http://www.movable-type.co.uk/scripts/latlong.html#bearing here]) to another <code>geo.Coord</code> instance. The bearing will be an {{wikipedia|absolute bearing}} (in the range 0–360).
|text = Returns the initial bearing (see [http://www.movable-type.co.uk/scripts/latlong.html#bearing here]) to another <code>geo.Coord</code> instance. The bearing will be in the range 0–360.
|param1 = coord
|param1 = coord
|param1text = Mandatory <code>geo.Coord</code> instance to calculate bearing to.
|param1text = Mandatory <code>geo.Coord</code> instance to calculate bearing to.
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printf("%.5f", c1.course_to(c2)); # prints "44.99564"
printf("%.5f", c1.course_to(c2)); # prints "44.99564"
}}
}}
==== distance_to() ====
==== distance_to() ====
{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.distance_to(coord);
|syntax = geo.Coord.distance_to(coord);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the great circle distance in metres to another <code>geo.Coord</code> instance. Note that this function ignores altitude.
|text = Returns the great circle distance in metres to another <code>geo.Coord</code> instance. Note that this function ignores altitude.
|param1 = coord
|param1 = coord
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.direct_distance_to(coord);
|syntax = geo.Coord.direct_distance_to(coord);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Returns the direct distance (cutting through the earth) in metres to another <code>geo.Coord</code> instance.  
|text = Returns the direct distance (cutting through the earth) in metres to another <code>geo.Coord</code> instance.  
|param1 = coord
|param1 = coord
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{{Nasal doc
{{Nasal doc
|syntax = geo.Coord.apply_course_distance(course, dist);
|syntax = geo.Coord.apply_course_distance(course, dist);
|source = {{fgdata file|Nasal/geo.nas|t=Source}}
|text = Calculates a new coordinate from a given course and distancce, and then updates the coordinates to the new set. Returns the <code>geo.Coord</code> instance.
|text = Calculates a new coordinate from a given course and distancce, and then updates the coordinates to the new set. Returns the <code>geo.Coord</code> instance.
|param1 = course
|param1 = course
|param1text = Mandatory course in degrees (in the range 0–360) to use in calculation.
|param1text = Mandatory absolute bearing (0–360) to use in calculation.
|param2 = dist
|param2 = dist
|param2text = Mandatory distance in metres to use in calculation.
|param2text = Mandatory distance in metres to use in calculation.
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=== PositionedSearch ===
=== PositionedSearch ===
{{Note|This is currently only used by the MapStructure code to run more efficient searches (i.e. the delta-search stuff for map-canvas.xml)}}
{{Nasal doc
|mode = class
|version = 3.0
|commit = {{fgdata commit|a9576e|t=commit}}
|text = This class can be used to show differences between FGPositioned (namespace: <code>positioned</code>) search queries. Although it is only used for [[MapStructure]] and the [[Nasal Browser]] as of 09/2016, it can also be used for other applications.
}}
==== new() ====
{{Nasal doc
|syntax = geo.PositionedSearch.new(searchCmd, onAdded, onRemoved[, obj]);
|text = Constructor function. Returns a new <code>geo.PositionedSearch</code> instance.
|param1 = searchCmd
|param1text = A mandatory function that will actually do the searching. It must return a vector containing the elements from the search.
|param2 = onAdded
|param2text = A mandatory function that will be called if a element has been added to the search results. The element added will be passed to this function.
|param3 = onRemoved
|param3text = A mandatory function that will be called if a element has been removed from the search results. The element removed will be passed to this function.
|param4 = obj
|param4text = Optional <code>'''me'''</code> reference. This will be used as the <code>'''me'''</code> reference in each of the above fucntions.
|example1 = var searchCmd = func(){
    return positioned.findAirportsWithinRange(10);
};
 
# This function will be called whenever an item is added
var added = func(apt){
    print("Airport ", apt.id, " added");
}
 
# This function will be called whenever an item is removed
var removed = func(apt){
    print("Airport ", apt.id, " removed");
}
 
# Create a new object, passing to it the search function to be used and the callbacks
var searcher = geo.PositionedSearch.new(searchCmd, added, removed);
 
# Actually update the searcher object
searcher.update();
}}
==== test() ====
{{Nasal doc
|syntax = geo.PositionedSearch.test([from[, to]]);
|text = Performs a test of the class. It benchmark's the amount of time it switch between searches for fixes at certain ranges.
|param1 = from
|param1text = Optional distance parameter in nautical miles for the first search for fixes. Defaults to 640.
|param2 = to
|param2text = Optional distance parameter in nautical miles for the second search for fixes. Defaults to 320.
|example1 = geo.PositionedSearch.test(); # prints the test results and changed elements
|example2 = geo.PositionedSearch.test(10, 50); # prints the test results and changed elements
}}
==== update() ====
{{Nasal doc
|syntax = geo.PositionedSearch.update([searchCmd]);
|text = Performs an search. It executes the search function and analyses the results.
|param1 = searchCmd
|param1text = Optional search function to use instead of the one given in <code>[[#new()_2|PositionedSearch.new()]]</code>.
|example1 = var searchCmd = func(){
    return positioned.findAirportsWithinRange(10);
};
var added = func(apt){
    print("Airport ", apt.id, " added");
}
var removed = func(apt){
    print("Airport ", apt.id, " removed");
}
 
var searcher = geo.PositionedSearch.new(searchCmd, added, removed);
searcher.update();
}}
==== _equals ====
{{Nasal doc
|syntax = geo.PositionedSearch._equals;
|text = Function that checks if two objects are equal. You must redefine this function to use <code>geo.PositionedSearch</code> for other uses.
|example1 = var searchCmd = func(){
    var vec = [];
    var max = rand() * 10;
    for(var i = 1; i <= max; i += 1){
        append(vec, i);
    }
    return vec;
};
var added = func(num){
    print(num, " added");
}
var removed = func(num){
    print(num, " removed");
}
 
var searcher = geo.PositionedSearch.new(searchCmd, added, removed);
searcher._equals = func(a, b){ return a == b; }
searcher.update();
print("====");
searcher.update(); # run again to see differences between both queries
}}


== Functions ==
== Functions ==
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{{Nasal doc
{{Nasal doc
|syntax = geo.elevation(lat, lon[, max_alt]);
|syntax = geo.elevation(lat, lon[, max_alt]);
|text = Returns the elevation in metres of a certain point on the scenery. See also {{func link|geodinfo}} (which is used internally).
|text = Returns the elevation in metres of a certain point on the scenery. See also {{func link|geodinfo()}} (which is used internally).
 
If the terrain altitude has not yet been loaded in the area identified by the coordinates, the function returns the ''nil'' value.
|param1 = lat
|param1 = lat
|param1text = Mandatory latitude coordinate.
|param1text = Mandatory latitude coordinate.
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=== format() ===
=== format() ===
{{Nasal doc
|syntax = geo.format(lat, lon);
|text = Returns the coordinate formatted as a string. The format will be the same as used for scenery tiles, e.g., <code>w010n50</code> (10 degrees West, 50 degrees North).
|param1 = lat
|param1text = Mandatory latitude coordinate.
|param2 = lon
|param2text = Mandatory longitude coordinate.
|example1 = var ac_pos = geo.aircraft_position();
print(geo.format(ac_pos.lat(), ac_pos.lon()));
}}
=== normdeg() ===
=== normdeg() ===
{{Nasal doc
|syntax = geo.normdeg(angle);
|text = Normalizes an angle to be in the range 0–360.
|param1 = angle
|param1text = Mandatory angle to normalize.
|example1 = print(geo.normdeg(45)); # print "45"
|example2 = print(geo.normdeg(-90)); # print "270"
|example3 = print(geo.normdeg(1060)); # print "340"
|example4 = print(geo.normdeg(-653)); # print "67"
}}
=== normdeg180() ===
=== normdeg180() ===
{{Nasal doc
|syntax = geo.normdeg180(angle);
|version = 2.12
|commit = {{fgdata commit|8c23d0|t=commit}}
|text = Normalizes an angle to be in the range -180–180.
|param1 = angle
|param1text = Mandatory angle to normalize.
|example1 = print(geo.normdeg180(96)); # print "96"
|example2 = print(geo.normdeg180(-96)); # print "-96"
|example3 = print(geo.normdeg180(256)); # print "-104"
|example4 = print(geo.normdeg180(-209)); # print "151"
}}
=== put_model() ===
=== put_model() ===
{{Nasal doc
|syntax = geo.put_model(path, lat, lon[, elev[, hdg[, pitch[, roll]]]]);
geo.put_model(path, coord[, hdg[, pitch[, roll]]]]);
|text = Places a model in the simulation at a given location and orientation. If successful, returns the model's root property as a <code>props.Node</code> object.
|param1 = path
|param1text = Path to the model as a string.
|param2 = lat
|param2text = Latitude coordinate.
|param3 = lon
|param3text = Longitude coordinate.
|param4 = elev
|param4text = Optional altitude. Defaults to <code>'''nil'''</code>, in which case the model will be placed on the terrain. Note that an error will be thrown if the terrain's elevation cannot be found, e.g., if there is no scenery tile loaded at the location.
|param5 = coord
|param5text = A <code>geo.Coord</code> instance, which, if given, replaces '''lat''', '''lon''' and '''elev'''.
|param6 = hdg
|param6text = Optional model heading. Defaults to 0.
|param7 = pitch
|param7text = Optional model pitch. Defaults to 0.
|param8 = roll
|param8text = Optional model roll. Defaults to 0.
|example1 = var path = 'Models/Geometry/glider.ac';
var coord = geo.aircraft_position();
var course = getprop("/orientation/heading-deg");
coord.apply_course_distance(course, 100); # Model to be added 100 m ahead
var model = geo.put_model(path, coord, course); # Place the default glider
|example2 = var path = 'Models/Geometry/glider.ac';
var coord = geo.aircraft_position();
coord.apply_course_distance(getprop("/orientation/heading-deg"), 100); # model to be added 100 m ahead
var model = geo.put_model(path, coord.lat(), coord.lon(), coord.alt(), 0, 45, 50); # Place the default glider
}}
=== tile_index() ===
=== tile_index() ===
{{Nasal doc
|syntax = geo.tile_index(lat, lon);
|text = Returns the current tile's index. Effectively a wrapper for {{func link|tileIndex()}}.
|param1 = lat
|param1text = Mandatory latitude coordinate.
|param2 = lon
|param2text = Mandatory longitude coordinate.
|example1 = var ac_pos = geo.aircraft_position();
print(geo.tile_index(ac_pos.lat(), ac_pos.lon())); # prints the index of the current tile
}}
=== tile_path() ===
=== tile_path() ===
{{Nasal doc
|syntax = geo.tile_path(lat, lon);
|text = Returns the current tile's path under <tt>''[[$FG_SCENERY]]/Terrain''</tt>.
|param1 = lat
|param1text = Mandatory latitude coordinate.
|param2 = lon
|param2text = Mandatory longitude coordinate.
|example1 = var ac_pos = geo.aircraft_position();
printfinddata(geo.tile_path(ac_pos.lat(), ac_pos.lon())); # prints the path of the current
}}
=== viewer_position() ===
=== viewer_position() ===
{{Nasal doc
|syntax = geo.viewer_position();
|text = Returns the current viewer position in the form of a <code>geo.Coord</code> object. Note that the altitude will be in metres.
|example1 = var v_pos = geo.viewer_position();
v_pos.dump();
}}


== Variable ==
== Variable ==
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|text = Radius of Earth in metres. This is almost equivalent to Earth's equatorial radius (6,378,137 m). Value: 6,378,138.12
|text = Radius of Earth in metres. This is almost equivalent to Earth's equatorial radius (6,378,137 m). Value: 6,378,138.12
}}
}}
{{Nasal namespaces}}
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