2 different Pedometer apps different result?

[dimme]

Hi I have been trying out two different Pedometer apps on the same exact walk on two different days. Pedometer FREE GPS +By ARAWELLA CORPORATION gives me a distance 0f 2.7 miles, and MapMyHike GPS Hiking app gives me a distance of 3 miles. Whats up don't they use the same components of the iphone.
Which one can I trust?

 

[lucasfer899]

Maybe one is using cell towers and one is relying solely on GPS?
Or they're using different mapping engines?
I don't know much about this though.