The use of linear referencing is widespread, ranging from storing bus routes to oil and gas pipelines. Our ability to locate any position along a line based on a distance value from the start of the line is done using the interpolation methodology. We want to interpolate a point location at any position along a line. To determine the position, we'll use simple mathematics to calculate the position along a line based on the distance from the starting coordinate.

For our calculation, we'll measure the length of the line and find a coordinate located at a specified length from the start of the line. However, the question of where the start of the line is will soon arise. The starting point of the line is the first coordinate in the LineString's array of vertexes that make up the LineString because a LineString is nothing more than a collection of points chained together.

This will lead nicely to our next recipe, which is a little...