A raster representation of the number of minutes it takes the fire to reach that location on the landscape from the ignition source. Output values are minutes only.
For MTT runs the Output resolution is determined by the Resolution of Calculations setting on the Minimum Travel Time tab.
For Farsite simulations the Output resolution is determined by the landscape resolution.
MTT Arrival Contour outputs are a vector representation of the MTT Arrival Time grid. As a contour map it is similar to a fire growth perimeter map and reflects the number of minutes it has taken the fire to reach that point on the landscape. The vector version has no units associated with the theme and cannot be queried within FlamMap.
MTT Arrival Contours can be saved as a multi-line shapefile feature from FlamMap. A polygon file can also be created by contouring the Arrival Time Grid and selecting the Create Polygon check box in the "Contouring" dialog. This can be saved in FlamMap as a multi-polygon feature and allow you to calculate areas for contour intervals.
For Farsite simulations it is suggested to save the Farsite Perimeters instead of contouring the Farsite Arrival Time grid. The visible perimeters can be modified in FlamMap with the "Farsite Perimeters" dialog.