The initial background to this app is described in my blog. I wanted something that I could use to provide a mobile, real-time equivalent of tracking services such as dopplr or Plazes.

It is currently showing my location in a Google Map at dalelane.co.uk/whereami.

bLADE GPS is an application written in C# for Windows Mobile Pocket PC devices.

It was written using the .NET 2 Framework and Smart Device Framework.

It is not a polished or finished application, and was written mainly as a way to play with code for a number of different areas, such as:

It uses my PDA's integrated Wi-Fi to look for nearby access points, comparing them against a list of known networks. For these networks, I've included the location coordinates, which can be uploaded to the server.

This is enough for most of the places that I typically go (home, work, my charity, family, friends, etc.) but if no known networks can be found...

I've written some very simple code to use my PDA's integrated GPS unit. It basically reads data from the GPS unit's COM port, and performs some pattern-matching to grab the coordinates from it, which can be uploaded to the server.

If GPS is also unable to identify my location (if it cannot get a fix, such as when I am indoors)...

It accesses my Outlook PIM to get the current appointment from my diary. If the 'location' field for the current appointment includes a recognisable location, this is uploaded to the server.

If it can find something that looks like a postcode in the location field, I try and translate that into GPS coordinates using streetmap.co.uk, using a URL that spoofs the form on their website and searching for the coordinates in the page HTML that is returned.

If all else fails, it prompts the user - providing a list of pre-defined descriptions that I can flick through with the D-Pad (e.g. "shopping" or "in Eastleigh"), but allowing me to overwrite it if I'm feeling descriptive! In the absence of any reply, it just uses "Out and about" as a default.

The server-side scripts are written in PHP. One web-service-style script accepts location updates from the Windows Mobile client and stores them, and another script generates the Javascript needed to display the stored updates in a Google Maps map.