Elevation Profiles

Elevation Profiles

Ride in central Connecticut with elevation data in the center

    Cyclists often ask how hilly was that ride.  The answer may be how hilly do you want it to be.  I looked at several sources of elevation profiles and for a specific ride got answers ranging from 778 feet to 2247 feet.  
    Most mapping programs use many short straight lines to approximate a curve.  On a hillside you could be thirty feet to the right or left and maybe ten feet uphill or downhill.  Take a ride of a hundred curves and there's lots of room for the errors to add up.  When your track was off the road by ten to 30 feet, if the mapping program actually moved you back on the road and then took your elevation then the elevation profile would be more accurate.  The table on the map has eight choices, but there is at most one right answer.
    GPS units with barometric altimeters often claim accuracies to within 30 feet of where you are horizontally.  I haven't seen one that gives the accuracy spec for altitude - say within ten feet above sea level.  
    When a friend wants to go on a hilly ride and you have a specific route in mind use VeloRoutes for route preparation.  If the friend wants gentle hills use Road Bike Rides to prepare the route.