WGS84 Earth Circles

BE ASTONISHED !

* If we are in New York and facing North, India is on our right ... but if we are in California, India is on our left.

* The route maps in Airline flight information show planes taking a long and big curvy paths and over far-flung territories when it fact the planes are taking the simplest and shortest path straight to your destination.

These are just some of the many astonishing realization when we try to relate places on a globe and on a flat paper map the we are more used to.

Discover and explore the interesting characteristic of living on a spherical object.
You we see a flat map being wrapped into a cylinder (Mercator projection) and then transform into a globe.
You will see a globe exploding into a flat map.
See your location on the globe and flat map and see it moves as the ground is being transformed.

No internet required.

LANGUAGES

English, Malay, Indonesian, Chinese, Japanese.

WHAT IS APPLICATION ABOUT

In this application, you graphically place markers of 2 geographical locations and the compelling animation will morph the Earth between globe and flat map showing you how the path between 2 locations are distorted and projected.

TECHNICALITIES

- The Earth is rendered using WGS84 specification, ie. it is an ellipsoid.
- Earths tilt is 23 degree.
- The shortest path between 2 locations is along a big circle. A big circle is a circle with the same radius and origin as the Earth.
- The path length is calculated by the application and not by the iPhones LocationManagers distance function.
- The coordinates used are in degrees, latitude first. ie. Latitude range is [-90,90] and Longitude range is [-180,180].
- When comparing the direction of the path with your actual location, please note that paths are with reference to True North. A magnetic compass checks the Magnetic North, so you may use it with will errors. iPhone has no magnetic compass.
- This application if for educational purpose only.

HOW TO USE

Tap the screen once to bring up the command buttons and tap again to hide them.

1) Press the i button to set your usage preference.
- Select the language from the list: English, Malay, Indonesian, Japanese, Chinese.
This language selection has no relation to the iPhones International Setting, so you do not have to change any iPhone setting.
- Select the unit of measurement: Kilometers (km) or Miles (mi).

2) Press the GREEN DOT button to specify your current location.
The map is zoomed into the current location showing a blink green dot and the shortest path towards the destination.
You may enter your coordinates in 3 ways:
- Type in using the iPhones keyboard.
- Press the Copy GPS arrow to copy the realtime GPS coordinates as your current location.
- Press the Select City arrow to pick from a name-list of places. The places are the coordinates of the respective countrys capital city.

3) Press the RED DOT button to specify your destination.
The map is zoomed into the destination location showing a blink red dot and the shortest path from your current location.
You may enter your coordinates in 2 ways:
- Type in using the iPhones keyboard.
- Press the Select City arrow to pick from a name-list of places.

4) Press the Flat Map button to animate from globe to flat map.

5) Press the Globe button to animate from flat map to globe.
Move you finger on the screen to rotate the globe in any direction to better view of the locations and the path between them.