# QGIS distance from point to line along a specific bearing

I've got a vector layer with points (representing customer locations) and another vector layer with a line (representing the coast line). I want to calculate a "smart" distance to coast. Specifically, I want to determine the shortest distance to the coastline within a specific range along a specific bearing.

For example, suppose a customer is located on a peninsula. At 0 degrees the distance is 1 mile to coast and at 180 degrees the distance to coast is 3 miles. In this case, I'm more interested in the distance at a bearing of 180 degrees. I run into many similar situations where the coastline weaves around so significantly that using a simple distance measurement yields unusable results for my purposes.

For each customer, I would store the bearing (in degrees) that I am wanting to use in this measurement.

Ideally, I'd like a function that allows me to find the shortest distance by specifying a bearing and a +/- range (in degrees), i.e., mypoint.min_distance_to_line_along_bearing(myline, 180, 15) ... which, in a perfect world, would return the shortest distance to the line in a bearing that is between 165 and 195 degrees.

I am using QGIS 2.8 on a Windows 7 PC. I hope this makes sense.