d2h - documentation

d2h - a MIDlet for final-glide-estimations.

A MIDlet is a small Java™-application running on a mobile wireless device.
This example is used for
estimations of a the final-glide on gliders.
After it is MIDlet is started, the screen of the device will look like show right.

Introduction:

Distance and height may be changed via keys.
Several types of gliders are installed are may be selected via keys.
The needed gliding-ratio is calculated and shown, additionally some security items had been added.
system-requirements: J2ME™, CLDC-1.0, MIDP-1.0

Usage:

Change of distance:
- By left/right-button to de/increase the distance in steps of 1 km.
- The numerical keys 1, 2 and 3 make use of fixed distances 10, 20 and 30 km.
Change of height:
- With down/up-button the height is changed by 100 meters.
- The numerical keys 4 to 9 will select fixed heights from 800 up to 2000 meter.
- Note: When entering the remaining height, considering the elevation of the landing field!
Change of glider:
- The '*' and '#' key will select a glider from a predefined list.
  Some properties are shown:
  - Description, type of glider.
  - Optimum-ratio at which speed (opt-ratio@speed).
  - Gliders save-ratio:
    The value is 66 percent of the gliders optimum-ratio.
    This savety item covers some uncertainties like wind,
    dirty wings (flies) and others.
    See example above '~(27.0)' = 41 * 2 / 3.
- With '0' key the present selected glider will be stored as favourite.
  This will be used next time the application is started.

Hints:

A 'need-save-ratio' is calculated and shown right of the numerical ratio.
As a safety feature it is assumed, that a minimum-height of 200 meter
is required when reaching the target airfield.
See example above '~(25.0)' = 25km / (1200 - 200) m.
A colored bar is shown on the display.
It indicates three states, show as colours green, yellow and red.
Here 'green' means, that the 'need-save-ratio' is fulfilled by the
'gliders save-ratio'.
In accordance to MIDP-1.0-specification devices with very small
monochrome displays (96x54pixel) are supported since version 2.0.
Due to the CLDC-1.0-specification floating-point
support is not included in the JavaVirtualMachine.
So the package "net.jscience.math.MathFP" is used for
floating-point-calculations, see jScience.net.

Versions:

2.1
input of touch-screens is processed if available
2.0
the layout was adapted to several display sizes,
even very small displays are supported
1.10
the favourite glider is stored in a persitent database (RMS)
1.9
the bars turns into yellow if airfield 'maybe' can reached
1.8
first public release