Hi,
I love maps, so I'm always interested to see mapping projects on Freelancer!
I develop apps for iPhone/iPod Touch/iPad and Mac, using Xcode and Swift.
You can see some examples of my work, and client reviews of my completed projects, on my Freelancer profile page.
Of course, the equation to determine velocity is distance / time. However, "Core Location" on iOS can also report the device's current speed, so you may want to use that?
I have written mapping apps using Apple Maps, Google Maps, Mapbox and OpenStreetMap. They all have different strengths, but I can advise on which may be most suitable for your app, if you haven't decided yet.
It looks like you may be new to Freelancer? Before starting the project, there should be a clear understanding of the details, the deadline, and the milestone payments.
If you'd like to reply to this message, we can discuss things further, before you make your decision on awarding the project.
Best Regards,
- Rob Dixon.
NOTE: This is an updated version of my bid on your original project (without the NDA)