In Steven Gould's Jumper series, the main character has the ability to teleport, and he eventually realizes he automatically does frame matching when doing so - no matter where on earth his origin and destination are, when he arrives, he is perpendicular to, and at rest in relation to, the ground.
I'm writing a story with a teleporter without frame matching. This is obviously going to limit how far he can safely teleport without stumbling / breaking a leg / becoming a grease stain; but what are the actual limits? The bulk of the story will be set in and about Seattle, WA, USA; how can I calculate safe distances and directions, or know how fast he'll be sent flying in which direction?
Edit: He can only teleport to locations he has already been or can see; so location isn't going to be an issue, only velocity and orientation.
It might be that I'll get better answers on the Math site, so I'll be posting there in the morning if nothing comes up here; but I thought I'd give Worldbuilding the first stab at it, since I'm more active here. I'll gladly delete here if this is deemed improper here.
Edit: It has been suggested that this is a duplicate of this question, which only asks what potential downsides of retaining momentum might be; but this is not the same question, as I am asking how to determine how to calculate a magnitude and direction for a specific known issue.