Date: 2009-10-01 00:02:00
xearth interactive page

Just a bit of work on xearth this week. I've made an interactive page where you can experiment with different xearth options including the new "overlay" feature.

The above image shows the current position of the earth as viewed from the sun.

Neither of the Mac links on work -- should I try the unix versions? Do the support alternate overlays?

Also, does sunrel work on the web site? It's showing the same position right now (nearly 8am CDT / 13Z) yet it's light here in southcentral North America.

In 1994, I had tried out xearth on my freebsd 2 computer in the early 90s but couldn't run it full time until I upgraded to 24MB of ram ($750 for two 8 MB SIMMS!) and I liked it so much that I disabled xlock and would clear my desktop after using my computer so I could see xearth running.
The page is currently an exact mirror of Kirk Johnson's last original xearth web page (from ~8 years ago), so it's full of broken links. In time, I plan to update this to reflect the new features of xearth and the latest information about the project. Currently I'm working on the original code development line instead of my old xearth for windows port. I plan to incorporate both the Windows and (new) OS X code into xearth to make it truly cross-platform.

The sunrel option should work, though sometimes at the edges of the globe it's hard to tell how far the sun goes (especially without city labels yet). Try turning off shading or increase the "Term" value (to 30 or so). Also try the mercator projection and increase Term to see a sharp edge. I'll have to provide some help on each of those options on the live page, as it's not always obvious. Perhaps some preset option combinations would be nice there too.

I've always liked xearth because it shows something concrete about the physical world (one could say it's a "real-world" program, ha ha). The new overlay feature, along with earthquakes and clouds and storm tracks (watch this space) will be a great enhancement.
Greg Hewgill <>