[Tfug] Wallpaper criteria

[John Gruenenfelder]

On Wed, Jan 9, 2013 at 3:12 AM, Bexley Hall <bexley401 at yahoo.com> wrote:
> Hi John,
>
>> Ever since I learned about it, I've been using Xplanet to generate my
>> background.  Over time, I've attempted to collect the best imagery I
>> could find for this purpose.  Primarily, this means very high
>> resolution maps of day and night Earth, as well as the best images I
>> could find of the other planetary bodies.
>
> I run xearth on my software development workstations.  It seems
> to fit the criteria I outlined previously (dark, no hot spots,
> etc.) *and* has the added benefit of acting like a "clock" for
> me (showing me a Sun's view of Earth so I can just watch to see
> where it is currently "noon" to get an idea of what the local
> time is).
>
> This works well for single monitor use or "X-in-a-window" but
> not well for multiple monitor use (too much "outer space")

The simplest explanation is that Xplanet is like xearth on steroids.
As its name implies, it can display any object in the solar system for
which you have a map image.  Various options let you control where the
viewer is and what they are viewing.  So, you could view the Earth as
seen from the Sun, or view Saturn as seen by an observer on the Moon,
etc.

> Agreed.  Especially in the case of xearth where there is very
> little detail besides outlines of continents and city names.

Since Xplanet lets you control precisely which map images are used and
also allows "arc" files, you could feed Xplanet a very simple map of
the Earth and apply the provided borders arc file so you can see the
political boundaries.

>> To make this ordeal easier to manage, I created a set of regular
>> Bourne shell scripts (i.e. no bash extras) to handle all of the
>> downloading, processing, and handling of program options.  They are
>> limited in some ways as they really only address use cases that I have
>> dealt with personally.  For example, the scripts support one or two
>> screens, and can display a different object on each screen, or,
>> optionally, one object can be replaced by a 'triple' which displays
>> three objects instead of one.
>
> For example?  (i.e., why?)

Uh, why what?  Why are the available modes the only ones available?
As I said, with little to no feedback these scripts solve and/or
simplify the ways in which I personally have been using Xplanet.

>> They make some assumptions, however,
>> like assuming that the user will always want the Earth to be one of
>> the objects and therefore the scripts always attempt to download the
>> most recent (every 12 hours) cloud map.  I've also never dealt with a
>> situation where I wanted a different image on each desktop/pane so the
>> scripts don't handle that.
>
> Ah, OK.  That's far more detailed than what xearth presents.  (it also
> requires the machines to have access to the outside world -- something
> that I don't allow development machines to do!  :< )
>
> Great!  I'll take a look at it.  I can always download *one* set
> of imagery and live with it "forever", right?

Well, to be more precise, it is my scripts which require Net access to
fetch the cloud map, the current satellite TLE files, and some
time-dependent data files downloaded by the TotalMarker helper tool,
in particular the locations and tracks of any storms of tropical
depression size or larger.  Xplanet then makes use of these various
data files to add features to the image.

As they stand now, the scripts allow you to turn off all of the
features requiring Net access with the exception of the cloud map.
There is no good reason for that; it's just something I've never
gotten around to.

>> Oh, and if you'd like to see what my wallpaper looks like right about
>> now, you can see it at:
>>    http://bach.as.arizona.edu/~johng/files/xplanet-wallpaper.jpg
>
> So, it shows the earth from a vantage point above a fixed location
> (e.g., beantown) instead of from a fixed point in space.

Yes, with my particular settings (all changeable), the viewer is
placed directly above latitude 25 deg. and longitude -72 deg. at a
height of 10 Earth radii from the Earth.  I don't know offhand, but
given how many options Xplanet has, I wouldn't be surprised if there
is some method for specifying an arbitrary point in space.

>> The brightness on the left is the Sun just about
>> to appear and it will take just over an hour and a half to move across
>> the screen entirely.
>
> ?? Why?  Doesn't it show the current terminator?

Just a matter of timing.  If you can see the Sun pass directly behind
the Earth then the terminator is necessarily perpendicular to the
observer.  If I were looking at my desktop at, say, 2PM, then I would
definitely see the terminator slowly moving from East to West,  And,
of course, my view settings are on a fixed point on Earth.  If I
alternatively chose to view from a fixed point like the Sun, then I
would see the rotation of the Earth and little, if any,  movement of
the terminator.

> My original request was for something largely *static*.  So that I
> can get the Windows machines to resemble the UN*X desktops better
> I.e., I can "86" xearth in favor of a static image on the UN*X
> desktops and apply that same sort of imagery to the Windows desktops.
> I'm trying to get some sort of uniformity to my workspaces that
> is easier to maintain and, more importantly, that I can relate to.

There is a port of Xplanet for Windows, though obviously you couldn't
use the scripts I wrote nor most of the tools they rely on.

> With lots of physical screens and virtual desktops, this quickly gets
> daunting!  (e.g., imagine opening an X server on a Windows machine to
> a Solaris client. etc.  "Now which CD-ROM drive do I need to put this
> disk in??"  :-/ )
>
> Different *planets* might be a good theme -- though I'm not sure I
> could differentiate the surface of Mars from that of Venus!  :-/

Indeed, it does start to get confusing quickly if your images are not
sufficiently different from one another.  Fortunately, in the case you
mention, telling the difference should be easy.  Mars is red.  Very
red.  Venus, on the other hand, is entirely opaque and the surface
cannot be seen at all.  It has a beige-greenish color.  In general,
all of the planets are sufficiently different that they you shouldn't
have trouble telling them apart.  A number of the Jovian and Saturnian
moons are also quite unique looking.


Well...  what the hell.  That's all the encouragement (or lack
thereof) that I need.  :)

I'll be back in a few days with version 3.0 of the scripts which will
make all Net using features optional, make no assumptions about what
object the user wants to view, and will no longer assume that the
final outcome is a wallpaper that should be displayed immediately.
Instead, you will be able have the scripts stop as soon as the
wallpaper image file is generated.

If you, or anybody else, has additional ideas, now is the time to speak up.


--John Gruenenfelder    Systems Manager, MKS Imaging Technology, LLC.
Try Weasel Reader for Palm OS  --  http://weaselreader.org
"This is the most fun I've had without being drenched in the blood
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        --Sam of Sam & Max