What do the colors on map overlays represent?


Overlays work on any map layer and provide a wealth of additional information to help you plan your next adventure. To help you understand what the various colors represent, here is a handy key:


US Contours

We use a smooth gradient slope shading color scheme to visually represent slope angles. 

  • Anything up to 20 degrees in slope is green
  • 21-28 is yellow
  • 29-40 is red
  • 41-55 is blue
  • 56-60 is black


Fire History (Pro feature)

Yellow represents older fire areas and as the fire areas get more recent they turn from orange to red. Active fires are demarcated with a fire icon or an X. 


Weather (Pro feature)

This overlay is a combination of satellite and radar. To help differentiate the intensity of falling rain or snow, different colors are used for radar. 

  • Light green: light rain
  • Dark green: light to moderate rain
  • Yellow: moderate rain
  • Orange: heavy rain
  • Red: very heavy rain or rain and hail
  • blue: snow
  • purple: freezing rain or sleet


Air Quality (Pro feature)

Our real-time air quality index is represented via a color-coded heatmap, where green indicates the cleanest air and red indicates the most polluted. 


AllTrails Map Layer

While this is not an overlay, we do get a lot of questions about the black dashed lines vs the blue dashed lines. Black dotted lines indicate no bikes while blue indicate bike friendly.


To read more about overlays, please click here: https://support.alltrails.com/solution/articles/222510-what-are-overlays