Sun-Path Projection Applet: This models the relationship between spherical and orthographic sun-path projection methods in 2D and 3D. This is an interactive applet so you can adjust the sun position by clicking and dragging it with the left mouse button or use the middle and right buttons to pan or rotate the view.


The aim of this applet is simply to demonstrate how the different projections methods differ as they are mapped over sun-path diagrams. To do this, the diagram smoothly transitions between spherical and orthographic mapping as well as between spherical, linear and stereographic projections. Use the DIAGRAM button menu (F5) to switch between these settings.

Spherical projection involves simply mapping the altitude lines from the celestial sphere directly onto the ground for a sky-dome map or a surrounding cylinder for an orthographic map). Linear projection maps altitude lines linearly along the radius of a sky-dome map or the y-axis of an orthographic map. Stereographic projection is a little more complex, but you can read more details about it on Wikipedia.

Display Options

You can use the OPTIONS button menu (F4) to change the main display settings. This menu lets you toggle overlay panels that show solar information, the world map and simple instructions. You can also use it to change the size of the world map, overlay world time zones or select different views of the model.

Using the Display Options… menu item (Ctrl+F4), you can determine what components of the sun-path diagram are displayed and how they are shown. This allows you to tailor the image to suit your particular demonstration or application.

The only real way to understand the use of these applets is to experiment, so please feel free to simply play about with it.






Mauricio Vicente 4 July, 2015 - 20:43

Very impressive blog! Thanks for all the information. I used to visit frequently for updates few years ago. Now the plugins aren’t working any more. Java blocked them for security reasons :(

Aliyu A. Aziz 2 September, 2013 - 08:56

Very impressive presentations!

Kang 27 August, 2013 - 14:45

Now I can easily imagine sun and shadow movement. Thank you for your great works.

Erick Mendieta 12 August, 2013 - 02:49

Thanks for the blog.

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