interpolation on shell script bash : I have a data file containing values of longitudes and latitudes (displayed on two columns) measured by a GPS along a profile at regular intervals. at a certain point on my profile, the GPS stopped working, hence in my data i have zeros instead of values of longitudes and latitudes. I want to interpolate between this fields to get values of longitudes and latitudes instead of zeros.

to be more clear here is a simple example of how my file looks like.
12  7
14  8
0   0
0   0
20  11
22  12

i want to interpolate where i got zeros. i am working on bash and i have no idea on how to do it