Kaz's Coding Examples

This example illustrates the use of the Google™ Map API as an Interface into an International Hotel/Resort Directory using basic GIS techniques. The NWS(National Weather Service) provides real time weather data to create the weather image.

  Just Click the map.

International Hotel/Resort Directory
  • AJAX is used to communicate and query data from the server.
  • MySQL Database of Hotels.com™/Travelnow.com™ International Hotel Directory
  • National Weather Services Live RSS/GIS data.

The list of hotels is retrieved in response to clicking on the Google™ Map.  The Google™ Map passes the Latitude/Longitude to a call back function which combines this information with the Search Radius value, and passes it to an AJAX routine that queries a MySQL database for properties within the search radius from the point clicked on the map.  The data is returned to an AJAX call back function as a executable piece of javascript that actually does the writing of the property list.

The Weather icon is a dynamic image created with PHP and a call to the National Weather Service's Live RSS feed.  The javascript that is returned from the previous step will set the src attribute of the image to a php script that actually creates and returns the image data.  FYI - some issues with the NWS feeds.

While I cannot take credit for the following (really cool) SQL query that does the radius search, I thought I would share it in case anyone else was hunting for one.  I cut and pasted it from some news group - if you'd like to take credit for it, drop me a line.  Basically, it's a trigonometry formula to find the distance between two point(as the crow flies).

SELECT id, Latitude, Longitude, (((acos(sin(($latitude*pi()/180)) * sin((latitude*pi()/180)) + cos(($latitude*pi()/180)) * cos((latitude*pi()/180)) * cos((($longitude - longitude)*pi()/180))))*180/pi())*60*1.1515) as distance
FROM Properties HAVING distance <= $distance

Still working on...

  1. Better error handling for weather image.  The problem is that the NWS has this feed down a times, therefore I need to have something more graceful besides the missing image icon().  Also, the NWS does not have data available outside the continental United States.
  2. City listbox lookup.  The "State Cities:" listbox is properly populated with cities in the state, but there is no mechanism to query those cities.
  3. More...