hey out there GISers, i am looking for a gps tracking service i can hook gps devices into and request their infos via a ruby on rails webapp. does anybody know some?
any help is appreciated!
thanks,
martin
a site which does similar things is eg.: www.cabulous.com
Most GPS devices do not transmit data. Put simply, GPS works by a constellation of satellites transmitting location data, which is triangulated by the GPS receiver. Thus, there is no need for GPS' to transmit data, only receive data.
If you want to design an automatic vehicle locator similar to cabulous you need a way to get the GPS coordinates from the GPS receive to some server.
Typically in the past this was done with specialised hardware, either using the mobile phone network or even proprietary radio networks. With the advent of internet-connected, GPS enabled smart-phones such as the iPhone or Nokia 5230, the hardware side is already done. All that is required is custom software to sit on the smart-phone, and a server somewhere to receive location data.
I don't know of any freely available services that might help you, but hopefully this will give you some idea of where to start.
As fmark pointed out, you cannot query any GPS - unless it has an uplink. The car/property trackers are useful if you need a long battery life with GSM uplink (up to about a month), but these usually do not expose their API.
If you have the choice of device, and could consider smartphones with GPS, you could settle for android devices with Google Latitude and query their position with the latitude API
http://code.google.com/intl/no/apis/latitude/
The option to roll your own client-side application remains. That is pretty much what cabulous does: Smartphones and a client-side app for the common phone operatings systems.
