Under ideal conditions, a track footprints) across a nice grassy field with a sufficient delay in time to allow bacteria reaction on the soil causing a good odor is probably the best type of track to have.
Compare the canine's nose Inside) to the human nose--it is much longer. The olfactory lobe of the canine is many times larger. Therefore, his brain's ability to register different smells is many times greater than ours.
Specially trained dogs can detect melanoma in moles on people. Dogs can detect by scent changes in moles.
All the existing literature on tracking introduces tracking by beginning with straight line tracks with a reward and/or article at the end.