track
Track segments to connect navigational waypoints
Syntax
[lattrk,lontrk] = track(waypts)
[lattrk,lontrk] = track(waypts,units)
[lattrk,lontrk] = track(lat,lon)
[lattrk,lontrk] = track(lat,lon,ellipsoid)
[lattrk,lontrk] = track(lat,lon,ellipsoid,units,npts)
[lattrk,lontrk] = track(method,lat,...)
trkpts = track(lat,lon...)
Description
[lattrk,lontrk] = track(waypts) returns
points in lattrk and lontrk along
a track between the waypoints provided in navigational track format
in the two-column matrix waypts. The outputs are
column vectors in which successive segments are delineated with NaNs.
[lattrk,lontrk] = track(waypts,units) specifies the
units of the inputs and outputs, where units is any valid
angle unit string. The default is 'degrees'.
[lattrk,lontrk] = track(lat,lon) allows
the user to input the waypoints in two vectors, lat and lon.
[lattrk,lontrk] = track(lat,lon,ellipsoid) specifies
the shape of the Earth using ellipsoid, which can be a referenceSphere, referenceEllipsoid, or oblateSpheroid object, or a vector of the form [semimajor_axis
eccentricity]. The default ellipsoid is a unit sphere
[lattrk,lontrk] = track(lat,lon,ellipsoid, establishes
how many intermediate points are to be calculated for every track
segment. By default, units,npts)npts is 30.
[lattrk,lontrk] = track(method,lat,...) establishes
the logic to be used to determine the intermediate points along the track between
waypoints. Because this is a navigationally motivated function, the default method is
'rh', which results in rhumb line logic. Great circle logic can
be specified with 'gc'.
trkpts = track(lat,lon...) compresses
the output into one two-column matrix, trkpts,
in which the first column represents latitudes and the second column,
longitudes.
Examples
Calculate Track and Display It on Map
The track function is useful for generating data in order to display tracks. Lieutenant Sextant is the navigator of the USS Neversail. He is charged with plotting a track to take Neversail from the Straits of Gibraltar to Port Said, Egypt, the northern end of the Suez Canal. He has picked appropriate waypoints and now would like to display the track for his captain's approval.
First, display a chart of the Mediterranean Sea.
load coastlines axesm('mercator','MapLatLimit',[28 47],'MapLonLimit',[-10 37],... 'Grid','on','Frame','on','MeridianLabel','on','ParallelLabel','on') geoshow(coastlat,coastlon,'DisplayType','line','color','b')
These are the waypoints Lt. Sextant has selected.
waypoints = [36,-5; 36,-2; 38,5; 38,11; 35,13; 33,30; 31.5,32];
Now display the track. With a display this clear, the captain gladly approves the plan.
[lttrk,lntrk] = track('rh',waypoints,'degrees'); geoshow(lttrk,lntrk,'DisplayType','line','color','r')
