User:Sourcerer/KML tool

Double check output - not thoroughly tested yet!

This calculator creates a KML file.

If Google Earth or another application that understands this file format is installed, it should launch and display the hashpoints for your specified date and graticule.

Bugs and requests

Please put bugs and requests on the discussion tab.

Usage

http://nbest.co.uk/kmlGeohash/index.php?date=2008-05-21&lat=52&lon=0&skins=2

• date - formatted yyyy-mm-dd - the default is today's date - alternatively try for example, 1 for tomorrow or -2 for the day before yesterday.
• lat - your graticule latitude - the default is 51 (Grenwich London).
• lon - your graticule longitude - the default is 0 (Grenwich London).
• skins - like an onion, the number of layers of points surrounding the home point - the default is 1 giving 9 hashpoints - the limits are 0 to 6.

Tests

These tests passed on a weekend. On weekdays when the 30W Time Zone Rule rule applies, things are a bit more chaotic.

• Test equator - Looks OK.
• Test round the back - The coordinates are shifted to prevent wrapping at +/- 179.999^o
• Australia - Australia looks OK.
• Atlanta - Atlanta looks OK.
• North pole - The coordinates are shifted to prevent wrapping at +/- 89.999^o
• South pole - The coordinates are shifted to prevent wrapping at +/- 89.999^o
• -50, -30 - South Georgia and Zavodovski islands look OK either side of 30W.

Source Code and Documentation

Source Code - Algorithm - 30W Time Zone Rule

Experiments

• {{#dow:2008|05|21}} -> 12824.94

• {{#md5:2008-05-21-{{#dow:2008|05|21}}|1|1}} -> 0.94961437806606
• {{#md5:2008-05-21-{{#dow:2008|05|21}}|2|1}} -> 0.36908385622475