Installing TerraTime
- How do I get TerraTime for my phone?
- What about iPhone, BlackBerry, Palm, ..?
- How much does TerraTime cost?
- Do I need to be online for TerraTime to work?
- How much phone memory does TerraTime need?
- What about battery usage?
- What are all these permissions that TerraTime is asking for?
Using TerraTime
- How do I install one of the home-screen widgets?
- How do I install the live wallpaper?
- My wallpaper isn't updating.
- My clock widget isn't updating.
- Why is it so slow?
- Why doesn't day + night = 24 hours?
- What do dawn and dusk mean?
- Why does TerraTime show a different sunrise and sunset time than ____________?
How do I get TerraTime for my phone?
Click to download for Android smartphones. If you use a non-Android phone, please see the next question…
What about iPhone, BlackBerry, Palm, ..?
TerraTime is only available for Android devices. No other platform on the market supports the full range of functionality required, including 3-axis orientation sensors, wallpaper, and home screen widgets.
How much does TerraTime cost?
The full version (including all features) costs US $2.99 on the Android Market, which includes future updates.
Do I need to be online for TerraTime to work?
Not usually. TerraTime's map and globe are created on the fly from high-resolution NASA images, downloaded as needed. So, a high-speed data connection is required to fetch these images the first time, and is required for live updates to clouds every few hours. Otherwise, the imagery is stored on your device after download, and no connection is needed.
The TerraTime clock doesn't require an internet connection at all.
How much phone memory does TerraTime need?
The application itself takes about 1MB. Because TerraTime includes live wallpapers and homescreen widgets, it's not compatible with installation directly to SD card.
The images used to make TerraTime work are stored on your device after downloading; this speeds up the various displays, and allows the map and globe to be updated even when you're offline. If you have a memory (SD) card installed, the images will be stored there, rather than using scarce internal memory. You can decrease this storage requirement somewhat by turning off Clouds, Polar Sea Ice, and City Lights, if you wish.
What about battery usage?
Unavoidably, the TerraTime widgets and live wallpapers use somewhat more battery power than lesser-featured clock widgets and static wallpapers. If battery life is a problem for you, the impact can be reduced by increasing the Update interval, accessed in Settings from the main application menu.
What are all these permissions that TerraTime is asking for?
Here's why each is needed:
- full Internet access
- to download the satellite imagery used to make the map and globe
- read phone state, view network state
- to ensure that you have a high-speed data connection before downloads take place
- location
- sunrise and sunset times depend on where you are
- start at boot, set wallpaper
- both essential to making the live wallpaper work
How do I install one of the home-screen widgets?
To install one of the widgets, long-press on an empty area of the home screen, select Widgets, then TerraTime Clock or Globe in the desired size:
- the small widget takes up the space of one icon
- the medium size uses the space of four icons (2 x 2)
- the large widget replaces nine icons (3 x 3)
- extra-large consumes the space of 4 x 4 icons, or one standard home screen panel on most devices
How do I install the live wallpaper?
In Android 2.1: press Menu from your home screen, select Wallpaper, then Live Wallpaper, and either TerraTime Globe or Map. Change settings if you wish, then touch Set Wallpaper.
In older versions of Android (1.x and 2.0): open Settings from the main TerraTime application menu, then select either Globe or Map, and check the box for Live wallpaper.
My wallpaper isn't updating.
On legacy versions of Android (pre-2.1), TerraTime makes the live wallpaper happen with a background process, and occasionally this can get stuck. To restart it, select Refresh from the main application menu.
Also, please note the following known issues with legacy live wallpaper:
- Wallpaper updates won't appear on your device's lock screen, but are still going on behind it.
- Live wallpaper isn't compatible with some alternative home screens and non-standard Android installations.
- Task killer apps can stop it dead; see the next FAQ for more details on this.
My clock widget isn't updating.
Like the wallpaper, the background process that updates the home screen widget will very occasionally die. If this happens, the Refresh menu item should update it manually and restart the process.
Note that if you have a "task killer" app running on your phone, this will stop TerraTime's clock by killing its process. Please exclude TerraTime from any auto-kill lists.
If the TerraTime clock widget or live wallpaper gets stopped for any reason, such as a killed process, it should automatically restart within 5 minutes (on Android 1.5) or 1 hour (on Android 1.6+). This 1-hour delay is a limitation of the Android platform.
Why is it so slow?
Downloading the various map images takes some time, even on a fast connection: these are big satellite photos. And creating an accurate day/night line involves a lot of calculations, especially given it's running on a phone.
In particular, it can take a minute to refresh the wallpaper when your phone is first turned on, due to all the other things that are happening during boot-up. Patience, Grasshopper!
Why doesn't day + night = 24 hours?
Length of day is sunrise to sunset. Night is dusk to dawn. And between day and night is twilight, the period between dawn and sunrise, or sunset and dusk. So, day + night + twilight = 24 hours (with a bit of margin for roundoff errors and the change from one day and the next).
What do dawn and dusk mean?
These two times are the beginning and end, respectively, of full darkness. Although there are a number of ways to define "darkness", the one I use is nautical twilight, the time when the sun is 12 degrees below horizontal.
Why does TerraTime show a different sunrise and sunset time than ____________?
You may see slight differences between the sunrise/set times shown here and in other places, including what you might observe yourself. There are several reasons why this happens:
- There are many different definitions of sunrise and sunset, mostly to do with just what part of the sun's disc is (or is not) visible above the horizon.
- You'll find even more definitions of dawn and dusk; obviously, twilight is a subjective measurement, depending on many factors. In this app, I use nautical twilight to determine dawn and dusk times (see previous question).
- A difference in location of only a few miles can change the time by a minute or two. By default, TerraTime uses your approximate location, within about 5 miles, which is usually good enough.
- The relative times are computed based on your phone's clock, and while this is generally pretty accurate, it's not perfect.
Finally, it's simply not possible to compute rise and set times with a high degree of accuracy, due to unpredictable variations in local conditions like horizon irregularities and atmospheric refraction. See the US Naval Observatory's page on the subject for a good discussion of the issues.