Real-Time Data Monitoring
Chart description

 The data are displayed in two different sets of charts as summaries every 15 minutes for one day or as daily summaries for 90 days. As new data is collected, it is placed on the right edge of the charts and the oldest data scrolls off to the left. To the right of the charts are a column of numbers showing the most recent summary. Check the upper right hand corner of the page to see the time these were recorded. Generally the data should be no more than 17 minutes behind the actual time, but sometimes there will be a longer delay in transmitting the data.

How do we produce automatic charts?

Special sensors measure temperature, rainfall and wind speed and transmit the values obtained to a data logger . The logger automatically checks each sensor every 10 seconds, keeps track of a running total or mean and records it every 15 minutes in a special permanent storage area. The logger is connected through a radio to a device several hundred meters away in the laboratory which is connected to our local area network (LAN). The LAN at the field station is part of a wider LAN connects all of STRI's field stations so that a logger at one field station, say at Galeta, can be accessed from a computer at another location as if it were in the next room. In this case, a computer in an office on Naos Island manages the data collection from each logger. A program, Loggernet, running on that computer sends a message every 15 minutes over the LAN and the radio to the logger and asks it to download the latest set of data. The data are appended to a file on the Naos server. A special graphing program, Real Time Data Monitor, reads this data every 15 minutes, updates the charts, and produces the graphics file which you see on your browser. We use another program to automatically send the updated graphics file to the ESP website every 15 minutes. The loggers, and most of the communications equipment and software are manufactured by Campbell Scientific Inc.

Currently, only the logger at the Isla Galeta Marine Laboratory is set up for display over the internet. Eventually, data from Barro Colorado Island and Bocas del Toro will be available.

Permanent display of the charts

You may wish to display one or more of the pages permanently. The web page for each chart will  refresh itself automatically every 15 minutes. The figures on each page are 1010x680 pixels, so to take full advantage of the size of your monitor, its resolution should be set to 1152x864 or 1024x768 pixels. Then you should remove one or more of the tool bars at the top and bottom of your browser in order to make the entire figure visible.

Tip 1: If you manually refresh the page just once at either 2, 17, 32, or 47 minutes after the hour, the new chart will then continue appear shortly after it has been updated on the web site.

Tip 2: If you use Mozilla or Firefox as a browser, you can have several different pages loaded at the same time and then view them by clicking on tabs at the top of the screen. This will allow you to have the 24 hour and the 3 month chart available and automatically updated at the same time. Netscape does not currently support tabs. To open a Chart under a tab, use Ctrl-click .

Chart summaries

The summaries displayed on each chart are usually either a total or a mean with a maximum or minimum. For example, rainfall is shown as the total millimeters that fell for each 15 minute period. Solar radiation is shown as total megajoules, a measure of energy, falling on a square meter every 15 minutes. Air and water temperatures are shown as means. Means are based on values recorded at the source every 10 seconds. Wind speed is shown as a mean and the maximum wind gust recorded over the 15 minute interval. Water level is shown as the mean number of centimeters above and below the local mean water level. Humidity is recorded as a percent, so a simple mean of the values is not technically appropriate and only the maximum and minimum is shown. The midpoint of the humidity maximum and minimum is shown in the column displaying the most recent data. Summaries for each day for 90 days is shown on a different page, and each data point represents a mean or a total taken over all of the 15 minute intervals for that day.

Wind direction is shown on a dial to the right of the main set of charts. The most recent wind direction is shown with the needle and the 7 or 8 most recent wind direction values are shown as circles on the face of the dial. The smaller paler circles are the oldest values.