Interesting pace planning tool for the London Marathon www.thepacingproject.com. More so in the biking world there are tools to plan your race strategy over the undulations you encounter.
It looks like TrainingPeak efforts with the pacing project seem to have the equivalent goal in mind for the major marathons.
It won’t help me though as there is no marathon in store for my aching legs this year. I’m halfing it at Hackney #runhackney. And also doing the North London Half. the latter is more hilly and more in need of the aforesaid pacing tool