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-
- Earth Screen Saver for Windows
-
- Version 2.0a Release Notes
- by John Walker -- kelvin@fourmilab.ch
- WWW home page: http://www.fourmilab.ch/
-
- INTRODUCTION
- ============
-
- The Earth screen saver displays an image of the Earth as currently
- illuminated by the Sun, from a variety of viewpoints. You can view
- the Earth from the Sun (day side), the night side, from the Moon, or
- from an arbitrary altitude above any point on the globe specified by
- latitude and longitude. Day and night regions of the globe are shown
- based on the current date and time. The image of the Earth shifts
- location on the screen every 10 minutes to avoid burning in the
- phosphor in one location.
-
- The Earth Screen Saver is in the public domain. You can do anything
- you like with it. The images are generated based on a global
- topographic map developed by the Marine Geology and Geophysics
- Division of the National Geophysical Data Center operated by the
- United States Department of Commerce, National Oceanic and Atmospheric
- Administration.
-
- INSTALLATION
- ============
-
- The Earth Screen Saver works only on 32-bit Windows systems such as
- Windows 95 and Windows NT; it cannot be used on Windows 3.x. To
- install the Earth Screen Saver, download the archive EARTHSCR.ZIP and
- extract the files from it with PKUNZIP. You will obtain:
-
- EARTH.SCR - Screen saver module
- README.TXT - This document
-
- Copy EARTH.SCR to your Windows directory (usually C:\WINDOWS), then
- from the Desktop option of the Control Panel, choose "Earth" as your
- screen saver and use "Settings.." to select the view you prefer.
-
- CONFIGURATION
- =============
-
- The "Settings..." button in the Control Panel/Display/Screen Saver
- panel displays a dialogue which allows you to select the view of the
- Earth and the size of the image. The image size defaults to "Auto",
- which fills 2/3 of your screen, but you can enter any size from 64
- pixels to the entire height of your monitor.
-
- You can view the Earth from the following vantage points:
-
- Sun (day side)
- This is the default. The illuminated hemisphere of the Earth
- is shown, rotating as the day progresses.
-
- Moon
- The Earth is shown as it currently appears from the Moon. The
- phase of the Earth is inverse to that of the Moon: at new Moon
- the Earth is full and vice versa.
-
- Night side
- The night hemisphere is shown. This can be handy for
- shortwave listeners interested in bands on which propagation
- is best at night.
-
- Above location
- The Earth is viewed from the given latitude, longitude, and
- altitude. The default altitude is that of geosynchronous
- Earth satellites. The finite resolution of the map image
- limits the detail you can see by entering low altitudes.
- Enter the latitude and longitude of the location you want to
- look down upon, in degrees, minutes, and seconds in the boxes,
- and don't forget to click the buttons to specify whether the
- latitude is North or South and the longitude East or West.
- Don't worry about getting the longitude and latitude
- absolutely precise--a couple of minutes of error don't make
- much difference in the appearance of the earth rendered at
- this scale. If you enter your own latitude and longitude,
- you'll see the Earth centred upon your location and be able
- to watch the progression of day and night.
-
-
- HOME PLANET
- ===========
-
- The Earth Screen Saver was developed based on Home Planet, a
- comprehensive Earth and sky simulator for Windows which displays the
- Earth, tracks satellites, asteroids, and comets, includes an
- extensible multimedia object catalogue, a simulated telescope for
- viewing the sky at any magnification or location, a database of more
- than a quarter million stars, and a complete hypertext help file and
- introduction to astronomy linked to the components of the program.
- Displays include the illuminated portion of the Earth, the Sky, the
- Telescope, the Earth as viewed from a satellite, the Moon, or the Sun,
- an orrery, panels displaying current information about the Moon and
- planets, and more. Real-time astronomical information can be exported
- to other applications via DDE. There's even a cuckoo clock (you can
- turn it off). Home Planet is in the public domain.
-
- For more information about Home Planet, visit the World-Wide Web page:
-
- http://www.fourmilab.ch/homeplanet/homeplanet.html
-
- UPDATE LOG
- ==========
-
- Version 2.0 (19 Apr 1996): Initial release. The first release is
- numbered 2.0 to keep it in sync with the related Sky screen saver.
-
- Version 2.0a (28 Apr 1996): Workaround for inane and undocumented
- misbehaviour in the Microsoft screen saver library. See the development
- log in the source release for the ugly details. This fixes the problem
- where the image would cease to be updated but the caption would continue
- to move around on the screen, cluttering it up.
-