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There are several ways how to download and view data from an ALA probe. Probably the most user-friendly way is to use the interactive graph that you can see in the rigth part of the html page. This graph (implemented as a java applet) displays at the given moment data from one probe channel in the selected time interval.
The displayed channel can be selected using the panel on the left. The way the data is displayed depends on the channel type. A channel of a "level" type (such as temperature) is displayed as a red line, possibly with additional vertical blue lines indicating data range in the given interval (this happens if the number of data is too large to be drawn separately). Also, the graph may indicate various pre-set levels (usually corresponding to some important level values) by horizontal red lines. A channel of a cumulative type (such as precipitation) is displayed as a series of blue columns with colmun height indicating sum of the data within the given interval. Display style can be modified by the "graph style" button. The graph displays all channels using the same time interval. The default interval can be modified using the buttons on the left ("day", "week", "month"), using the text fields at the top, or (only to make the interval narrower) by dragging the mouse along the desired interval. Every interval change forces the browser to retrieve data from the server. For large intervals this can be a time-consuming operation. If the chosen time interval contains the latest data or current time (this is true, for example, at the beginning or after pressing one of the "day", "week" or "month" buttons), the graph will be automatically updated so as to stay uptodate. The interval will move forward in time while maintaining its length. There are two modes of graph update - either based on the local time, or whenever server receives new data from the probe. You can switch between these two modes using the "update" button. Indication of the update (and its type) in in the upper left corner of the graph. The resolution of the y-axis (data axis) is automatically adjusted so as to display all available data. This interval too can be adjusted - either using the text fields or dragging a mouse with right button pressed. You can adjust both intervals simultaneously by dragging a mouse and pressing the Ctrl button. This method can also be used to adjust the y-axis in case you have a one-button mouse. Cursor coordinates are displayed either next to it, or in the bottom left corner. You can switch between these by clicking a mouse button. You can navigate the history of displayed screens using the "back" and "forward" buttons. Probe data (within the selected time interval) can also be displayed in a table using the "data table" button. This data can then be saved in two formats - format ALA and format noel2000. The last button in the left panel changes page encoding. The "ALA" button displays the homepage of system ALA. The "help" button displays this help. |
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send your enquiries to the system administrator on milan@sekanina.cz
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