When you think of weather, what comes to mind? Probably one of the first things is the temperature. Another is the humidity. There's also wind speed and direction, among many other variables. These measurable characteristics of our weather are classified as properties by WeatherSnoop 3.
All properties have several things in common:
The Agent works hand in hand with its weather source to provide information for those properties that are supported. This means that each weather source has its own specific set of properties. For instance, the Davis weather stations can, with the correct sensors, provide ultraviolet and solar radiation information. Other stations may not have these sensors and therefore cannot provide those values.
In essence, a weather source's capabilities will determine how many properties it provides to WeatherSnoop 3.
While most properties are measured, some are derived, or calculated. For instance, temperature and humidity are measured, while dew point can be calculated from the previous two.
When possible, WeatherSnoop 3 will obtain the values of properties from the weather source itself. In cases where a weather source does not provide certain values, those will be calculated.
Properties are available for viewing in the Properties window. To see this window, select the Properties menu item from the View menu. You can also use the Command-Shift-W shortcut to view the window.
The window contains a table listing all of the properties for the weather source. Depending on the width of the window, you may need to use your mouse or track pad to scroll the contents of the table to the right to see all of the available columns.
The window above contains properties for the Davis Agent; the list of properties will vary according to your Agent.
Each property has the following attributes: name, value, updated, unit, color, calibration offset, minimum value today and maximum value today.
The property is a name which reflects what the property represents on the weather source. You can rename the property to something more specific by double clicking the name and typing in a new name.
This attribute shows the date and time that the current value was acquired. Depending upon how often the value is updated at your weather source, and how often WeatherSnoop 3 asks for the data, the date and time will change. This attribute is not editable.
The most recently obtained value is shown in the Value column, and is reflected in the units specified by the Unit column. You can click on the unit name and use the drop-down menu to change to a different unit. This action is global in that it affects all views for that property in other windows.
In some instances, a property will have only one unit, or no units at all. In the latter case, the Unit column simply contains “Default Unit.”
The color property is used when plotting the archived values of the property on a graph. You can click on the color name and select a different color for a specific property. Any graphs showing that property will have their color automatically updated.
Sometimes it is necessary to adjust values that may be off or need calibration. The calibration offset is a number that is added to the property's value, and can be either positive or negative. Note that the calibration offset is unit agnostic. If you change the unit, you will need to change the calibration offset accordingly.
In addition to the calibration offset, the calibration factor is used to manipulate the value of a property. Unlike the calibration offset, which adds the offset to the value, the calibration offset is multiplied by the value AFTER the calibration offset is applied. The calibration factor, like the calibration offset, is also unit agnostic.
Each property maintains both a minimum and a maximum value for the current day. This at-a-glance information is helpful to understand weather extremes during the course of the day. At midnight local time, both of these values revert to the current value, effectively being “reset” for the new day.
These values are also updated when archived data is obtained from the station, and are reflected in the minimum/maximum triangle indicators on most gauges.
You should now be familiar with the concept of the property, as well as the Properties window. Our next topic will be Viewing Data With Instruments.