How the network works

Getting data from the weather station in the field to the myWeather website has been a learning process. After experimenting with many “solutions” the method described below had proved to be the most reliable and cost efficient.

At the weather station site, a refurbished CSAG-supplied computer which runs linux is connected to each weather station console. Custom written software (in Python) pulls five minute averaged data from the console and sends this data to CSAG over the internet. Remote sites with permanent internet connection send data to CSAG directly over the internet (this is first prize but rarely the case) otherwise data is sent to CSAG via General Packet Radio Service (GPRS) offered by the cell phone networks.

In the absence of a permanent internet connection at the weather station site, a GPRS terminal is also connected to the linux-based PC. GPRS facilitates instant connection to the internet and information can be sent or received immediately as the need arises; no dial-up modem connection is necessary. (GPRS users are sometimes referred to be as being "always connected"). Data sent via GPRS from a weather station travels from the GPRS modem to the network provider, from here to the internet and from the internet to CSAG. This happens every five minutes for each respective station. The GPRS service thus facilitates the quick and efficient transfer of information across a cell phone network. As a line of data is very small (31 bytes), GPRS is far and away the most economical solution for us in transfering data to CSAG when there is no permanent on-site internet connection. For more on GPRS, click here and here.

Data coming into CSAG is received and placed into an open source database (MySQL) where, again, custom written software accesses it for display on the myWeather web site. Below is a schematic of the data flow where lines with arrows represent a wireless/internet/GPRS connection and lines with no arrows show hard-wired connections.