How to load a TIFF image like a graph in C++ BOOST

I want do load a tiff image (GEOTIFF with pixels with float values) like graph in boost C++ (i'm a newbie in C++). My goal is use the bidirectional Dijkstra from source A to target B to get more performance.

Boost:GIL load tiif images:
std::string filename( "raster_clip.tif" );
rgb8_image_t img;
read_image( filename, img, tiff_tag() ); 

But how convert to Boost graph? I am reading the documentation and looking for examples but I have not yet been able to implement it.

Similar questions and examples that i found:

Shortest path graph algorithm help Boost;

http://www.geeksforgeeks.org/shortest-path-for-directed-acyclic-graphs/

I am currently using the scikit-image library and use skimage.graph.route_through_array function to load graph with array in python. I use GDAL to get an array by load image as suggested by @ustroetz in this example Here:

    raster = gdal.Open("raster.tiff")
    band = raster.GetRasterBand(1)
    array = band.ReadAsArray()

Example of TIFF (was converted to PNG after upload) is: