Press this button to launch GlobeView:
Just press the button above to try the GlobeView Program!
NOTE: GlobeView must download a 250 kilobyte image before it comes up, so you may have to be patient.
Sometimes the applet will fail to load on the first try. Try clicking SHIFT-Reload to try again. (SHIFT-Reload is required to reload applets.)
Please send bug reports, suggestions, and kudos to me at cmbruns@rotatingpenguin.com. Please include messages on the Java Console, if any, with bug reports.
Using the mouse
- CLICK with the mouse on a point to center the map on that location. When the center point is not on the equator, the resulting projection is an OBLIQUE projection, meaning that the underlying generating globe is rotated before the projection is computed.
- MOVE the mouse over a geographic position to read the geographical coordinates in the status bar at the bottom of the window.
- DRAG with the mouse to zoom or pan (Rotate XY). Use the MOUSE menu to switch between these behaviors. When Rotate XY is selected, the center of the map can be changed.
The projections
When browsing different projections in GlobeView, the scale, orientation, and shape of the central point on the map will remain the same. For sufficiently small areas (high zoom level), all the projections will look the same. Viewing large regions of the earth's surface, on the other hand, reveals dramatic differences between the projections.
Azimuthal Equal Area: | Relative areas of land masses are correct. | |
Azimuthal Equidistant: | Relative distances from the center point of the map are correct. | |
Equirectangular: | The simplest projection. Also known as Plate Carée or Cylindrical Equidistant. Longitude is plotted on the X-axis; latitude is plotted on the Y-axis. | |
Gnomonic: | All great circles (e.g. the equator, lines of longitude, the day/night terminator) are straight lines. Imagine a light source at the center of the earth projecting an image of the earth onto a plane. Distortions are extreme at the edges of the map. No more than one hemisphere can be seen at one time. | |
Mercator: | Many world maps use this projection. Compass directions (loxodromes or rhumb lines) between locations are correct. Size distortions are extreme at the top and bottom of the map. | |
Orthographic: | The earth as it would appear if viewed from an infinite distance. No more than one hemisphere can be viewed at one time. | |
Perspective: | The earth as it would appear if viewed from a finite distance. No more than one hemisphere can be viewed at one time. | |
Sinusoidal: | Relative areas of land masses are correct. | |
Stereographic: | An azimuthal projection that is conformal (see below) Size distortions become large at the edges. |
Attributes of projections
- Conformal Projections: The correct shapes of small features are preserved. In other words, shapes are not distorted. It is impossible for a projection to be both conformal and equal area. Examples: Mercator, Stereographic
- Equal Area Projections: Relative areas of landmasses and other features are preserved. In other words, sizes are not distorted. It is impossible for a projection to be both conformal and equal area. Examples: Sinusoidal, Azimuthal Equal Area
- Azimuthal Projections: Directions from the center point of the map are preserved. Examples: Azimuthal Equidistant, Azimuthal Equal Area, Perspective, Orthographic, Stereographic
Links
- History of GlobeView
- Blue Marble images of the earth's surface
- Serge Stroobandt's radio propagation page: How to use globeview to optimize your ham radio performance.
- Paul Carlisle's Earth Viewer
- John Walker's Earth and Moon Viewer
- Dirk Djuga's WinGlobe Earth Viewer
- 1 km AVHRR global satellite image data
- GTOPO30 elevation data
- Rotating Penguin home page