need help calculating point between two coordinates.

[PeteDK]

Hi there

I'am working on a route comparison tool for carpools.

The route comparison is based on 'steps' retrieved from google maps
GDirection. These steps vary in length and i use the coordinates at
the beginning of each "step". However, sometimes the distance of these
steps is too long(ex. driving 30-40 km. on the freeway). Therefore i
would like to calculate/find the coordinate located in between two
given coordinates.
Lets say one step starts at:
56.043185,9.922714
and ends at:
56.234287,9.864521

I would then like to calculate the point right in the middle of these
coordinates.

I use the haversine form to calculate the distance between
coordinates, but im not sure whether or not this can be used for the
same purpose.
http://www.mpi.nl/world/persons/private ... versine.py

I apologize if this thread has been posted the wrong place

any help is greatly appreciated!

kind regards.

Pete

 

[Steven D'Aprano]

Hi there

I'am working on a route comparison tool for carpools.

The route comparison is based on 'steps' retrieved from google maps
GDirection. These steps vary in length and i use the coordinates at the
beginning of each "step". However, sometimes the distance of these steps
is too long(ex. driving 30-40 km. on the freeway). Therefore i would
like to calculate/find the coordinate located in between two given
coordinates.
Lets say one step starts at:
56.043185,9.922714
and ends at:
56.234287,9.864521

I would then like to calculate the point right in the middle of these
coordinates.

Can you assume that the coordinate system is virtually flat between those
points? That is, are the distances small enough that the curvature of the
earth isn't relevant?

If so, the following should be close enough:

def midpoint(a, b):
"""Return the two-dimensional point midway between points a and b."""
x = (a[0] + b[0])/2.0
y = (a[1] + b[1])/2.0
return (x, y)

Otherwise, you can probably start here:

http://www.geomidpoint.com/methods.html

http://mathforum.org/library/drmath...rical&textsearch_bool_type=and&topics=physics