Converting Between English & Metric Units

To avoid confusion and unexpected results best practice would be to plan ahead and use all metric or English input and output units for a run. Even though output products can be converted it is recommended to Change output defaults to desired units before running.

Changing between metric and English units is handled differently for inputs and outputs;

• Input unit options only identify the units users enter, switching units does not convert the entered values.
• On the other hand, output unit options available in the "Preferences" and "Create/Modify Legend" dialogs will convert values of those outputs to the new selected units.

NOTE: Auxiliary Grid Theme units are aways Class and cannot be changed.

Input Options

When using the Weather Stream Editor changing the Units: list box does not convert the values in the loaded Weather Stream (.WXS) File, only the column headers. Users are responsible for adjusting  the wind speed, precipitation, or temperature values when switching between metric and English units. The "Edit Wxs Values" dialog is a handy tool for converting units in the Weather Stream (.WXS) File.

Similarly when inputting winds for a FlamMap run (Inputs tab) changing the Wind Speed Units: list box does not convert the Wind Speed: values.

North American METAR/ASOS/AWOS (airport) observations and NDFD/RTMA/UTMA forecast products are in kts/hour@10 meters. For fire behavior purposes this is equivalent to mph@20 feet.

Output Options

The "Create/Modify Legend" dialog for many outputs provide options to convert between metric and English units. To avoid unexpected results that can occur when changing units take the following precautions,

• when using a Predefined Legend do not change the units,
• make sure to have at least one or two Decimal Places: set when converting.