Set or query roll angle of camera for geographic globe
Set Roll and Mode
camroll( sets the camera roll to
automatic mode, enabling the geographic globe to determine the roll angle based on plotted
data. The mode defaults to automatic when you create a geographic globe. If you interact
with the globe using your mouse, then the mode switches to automatic.
Change Roll Angle of Camera
Create a geographic globe. Position the camera near Mount Kilimanjaro by specifying a latitude, longitude, and ellipsoidal height. Set the pitch angle to 0 degrees, so that the camera points across the summit.
uif = uifigure; g = geoglobe(uif); campos(g,-3.1519,37.3561,5500) campitch(g,0)
By default, the roll angle is 0 degrees. Rotate the mountain in a counterclockwise direction by increasing the roll angle to 30 degrees.
Animate Changes to Roll Angle
Create a geographic globe. Position the camera near Mount Washington by specifying a latitude, longitude, and ellipsoidal height. Change the heading and pitch angles so that the camera faces the mountain.
uif = uifigure; g = geoglobe(uif); campos(g,44.2668,-71.3849,1757) camheading(g,90) campitch(g,0)
Animate the view by incrementally changing the roll angle. As the roll angle increases, the mountain rotates in a counterclockwise direction.
for roll = 0:5:180 camroll(g,roll) drawnow end
Get Information About Camera View
Get the position and the heading, pitch, and roll angles of the camera. Use this information to control the view of a different geographic globe or to automate navigation.
Create a geographic globe. Navigate to an area of interest using your mouse or gestures. For this example, navigate to an area around Hawaii.
uif = uifigure; g = geoglobe(uif);
Query the latitude, longitude, and ellipsoidal height of the camera, and assign each to a variable.
[camlat,camlon,camh] = campos(g)
camlat = 18.1781 camlon = -155.9297 camh = 6.6664e+04
Query the heading, pitch, and roll angles of the camera, and assign each to a variable.
heading = camheading(g) pitch = campitch(g) roll = camroll(g)
heading = 16.7613 pitch = -24.1507 roll = 359.9977
Use these values to control the view of a different geographic globe. For example, create a new geographic globe and programmatically set the view.
uif2 = uifigure; g2 = geoglobe(uif2); campos(g2,camlat,camlon,camh) camheading(g2,heading) campitch(g2,pitch) camroll(g2,roll)
Preserve Camera View
Preserve the position and the heading, pitch, and roll angles of the camera by setting the camera modes to manual. If you do not set the camera modes to manual, then the camera view resets when you plot new data.
Import a sample route along roads in Massachusetts using the
gpxread function. Create a geographic globe with a road map
and no terrain data. Preserve the basemap and terrain settings by using the
hold function. Then, navigate to an area near Eastern
Massachusetts using your mouse.
track = gpxread('sample_tracks.gpx','Index',2); lat = track.Latitude; lon = track.Longitude; height = track.Elevation; uif = uifigure; g = geoglobe(uif,'Basemap','streets','Terrain','none'); hold(g,'on')
Set the camera modes to manual and plot the data. Note that the camera position does not change.
campos(g,'manual') camheight(g,'manual') camheading(g,'manual') campitch(g,'manual') camroll(g,'manual') geoplot3(g,lat,lon,height,'LineWidth',3)
How Camera Orientation Affects Globe View
The values of the camera heading, pitch, and roll angles affect your view of a geographic globe. Mapping Toolbox™ references these values to the globe using a north-east-down (NED) coordinate system. As a result, when the heading, pitch, and roll angles of the camera are zero, the camera sits on a plane that is parallel to the tangent plane of the globe at the current latitude and longitude. For more information about NED coordinate systems, see Choose a 3-D Coordinate System.
Change your view of a geographic globe by changing the heading, pitch, and roll angles of the camera:
Heading — Rotate the camera about its z-axis, which shifts the view left or right. Move the view to the right by increasing the heading angle.
Pitch — Rotate the camera about its y-axis, which tilts the view up or down. Tilt the view up by increasing the pitch angle.
Roll — Rotate the camera about its x-axis, which spins the camera around its lens. Spin the view counterclockwise by increasing the roll angle.
When the pitch angle is near –90 (the default) or 90 degrees, the camera loses one rotational degree of freedom. As a result, when you change the roll angle, the heading angle may change instead. This phenomenon is called gimbal lock. To avoid the effects of gimbal lock, call the
camheadingfunction instead of the
1 Alignment of boundaries and region labels are a presentation of the feature provided by the data vendors and do not imply endorsement by MathWorks®.