Yes, for weight bearing exercise like walking in place, a heavier person will burn more. In coming up with a calorie estimate, Spark takes your weight into account.
A GPS tracker is based on distance travelled, which is great for things like walking, running or cycling outside. But it is not going to produce accurate results for walking IN PLACE.
There is an online (and free) calorie calculator built into Spark - go to the My Fitness tab at the top of the page, then follow the My Fitness tracker.
WATP (at least the basic ones) counts as fairly moderate walking, so perhaps track this as X minutes of walking at 24 min/mile (2.5 mph).
The reasonable man adapts himself to the world; the unreasonable one persists in trying to adapt the world to himself. Therefore all progress depends on the unreasonable man.
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