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track

Geographic track points from waypoints

    Description

    Track Points Along Unit Sphere

    [lattrk,lontrk] = track(waypts) finds the latitude and longitude coordinates of track points between the waypoints specified by waypts. This syntax references the coordinates to a unit sphere and calculates track points using rhumb lines.

    example

    [lattrk,lontrk] = track(lat,lon) finds the coordinates of track points between the waypoints with coordinates lat and lon. This syntax is equivalent to track(waypts), where waypts = [lat lon].

    [lattrk,lontrk] = track(___,units) specifies the angle units units for the inputs and outputs.

    Track Points Along Ellipsoid

    example

    [lattrk,lontrk] = track(lat,lon,ellipsoid) specifies a reference ellipsoid for the coordinates.

    [lattrk,lontrk] = track(lat,lon,ellipsoid,units,npts) specifies the number of points to calculate between each waypoint.

    Additional Options

    [lattrk,lontrk] = track(method,___), where method is "gc", finds track points along great circles (for a sphere) or geodesics (for an ellipsoid). The default for method is "rh", which finds track points using rhumb lines.

    mat = track(___) returns the latitude and longitude coordinates of the track points in the matrix mat.

    Examples

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    Specify the coordinates of several waypoints in the Mediterranean Sea. Then, find the coordinates of track points between the waypoints.

    lat = [36 36 38 38 35 33 31.5];
    lon = [-5 -2 5 11 13 30 32];
    [lattrk,lontrk] = track(lat,lon);

    Create a map of the area. Display the waypoints using red circle markers and the track points using a blue line.

    GT = readgeotable("landareas.shp");
    worldmap([28 47],[-10 37])
    geoshow(GT)
    geoshow(lat,lon,"DisplayType","point","Marker","o","MarkerFaceColor","r")
    geoshow(lattrk,lontrk,"DisplayType","line","Color","b")

    Import a shapefile containing worldwide land areas into the workspace as a geospatial table. Extract the reference ellipsoid for the land areas from the table.

    GT = readgeotable("landareas.shp");
    ellipsoid = GT.Shape.GeographicCRS.Spheroid;

    Specify the coordinates of several waypoints in an area surrounding the Mediterranean Sea. Then, reference the coordinates to the ellipsoid and find the coordinates of track points between the waypoints.

    lat = [36 36 38 38 35 33 31.5];
    lon = [-5 -2 5 11 13 30 32];
    [lattrk,lontrk] = track(lat,lon,ellipsoid);

    Create a map of the area. Display the waypoints using red circle markers and the track points using a blue line.

    worldmap([28 47],[-10 37])
    geoshow(GT)
    geoshow(lat,lon,"DisplayType","point","Marker","o","MarkerFaceColor","r")
    geoshow(lattrk,lontrk,"DisplayType","line","Color","b")

    Input Arguments

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    Latitude and longitude coordinates of the waypoints, specified as a two-column matrix. The first column of the matrix contains the latitude coordinates and the second column of the matrix contains the longitude coordinates.

    Data Types: single | double

    Latitude coordinates of the waypoints, specified as a vector.

    The size of lat must match the size of lon.

    Data Types: single | double

    Longitude coordinates of the waypoints, specified as a vector.

    The size of lat must match the size of lon.

    Data Types: single | double

    Angle unit, specified as one of these options:

    • "degrees" — Degrees

    • "radians" — Radians

    Data Types: char | string

    Reference ellipsoid, specified as a referenceSphere object, a referenceEllipsoid object, an oblateSpheroid object, or a two-element vector of the form [semimajor_axis eccentricity], where semimajor_axis is the length of the semimajor axis and eccentricity is the eccentricity. The values semimajor_axis and eccentricity must be of data type double.

    The default value of [1 0] represents the unit sphere.

    Number of track points to include between each waypoint, specified as a positive integer.

    Data Types: double

    Track method, specified as one of these options:

    • "rh" — Find track points along rhumb line paths.

    • "gc" — For spheres, find track points along great circle paths. For ellipsoids, find track points along geodesic paths.

    Data Types: char | string

    Output Arguments

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    Latitude coordinates of the track points, returned as a column vector.

    The track function separates the track points that connect each pair of waypoints by using NaN values. As a result, there is a NaN value every npts elements (excluding the last element).

    Longitude coordinates of the track points, returned as a column vector.

    The track function separates the track points that connect each pair of waypoints by using NaN values. As a result, there is a NaN value every npts elements (excluding the last element).

    Latitude and longitude coordinates of the track points, returned as a two-column matrix equivalent to [lattrk lontrk].

    Version History

    Introduced before R2006a

    See Also

    Functions