Friday, February 26, 2010


I came across this concept recently--it is laid out pretty well in a Wikipedia article if you want some more details.  Basically, you use it to represent a latitude/longitude pair as a single set of characters.  There are two basic features to it that are pretty cool:

  • Each successive bit of information provides additional accuracy so that the location of the point is gradually refined.  This also allows the same formula to handle various levels of precision.
  • The bits that represent latitude and longitude are interpolated with one another.  That means that a single short piece of information represents the values in two dimensions.  This is especially useful for matching and storing unique point values in a database

This is a two-way hash...a point can be encoded and decoded.  There is a loss of precision...the final representation does not match the input value exactly, but is within a defined margin of error.

It looks much better than latitude and longitude values when passed in a URL, and it is easy enough to calculate that it is amost cost-free to use.

Monday, February 1, 2010

Drupal security

Big thumbs up to Drupal on security.  There were a few meager attempts to hack into this site.  The IP addresses track back to the ministry of education in Thailand...usually this kind of stuff hits my sites from China (though, given the world population distribution, that might just be the law of averages working).  In any case, the standard security of Drupal was enough to keep these casual hackers at bay.

And here I thought nobody was visiting this site...