It is better to show than tell:
On this image, the layer below the colorful shape is a trivial heat map in raster format.
The colorful shape is the product of the
In order to find the cell indexes for the start and end points, I am using the calculation shown in the second answer of this thread: How to extract value from a raster based on lat and lon? (I have used the first one also as a test, ending in the same results.).
As you can see from the arrows on the resulting image, the start/end points seem to be displaced in accordance to the starting points of the corridor.
The points' coordinates are in srid 4326.