The map seen here is of the ‘Willamette River’ historical channels in Oregon, US state in Pacific Northwest. The map is done by cartographer Dan Coe, shows the history of a river.
Map consists of a flow of a river generated by method of aerial radar technology called Lidar, Lidar data is collected by low-, slow flying aircraft with equipment that shoots millian of the laser points to the ground. When the data is studied, an amazingly accurate model of the ground can be mapped.
In the Willamette river map, the shades of white and blue shows elevation. A lidar digital elevation model of the Willamette river displays a 50 foot elevation range, from low elevation displayed in to white to higher displayed in dark blue. The pure white colour is the baseline(the zero point), and the dark blue is 50 foot than the baseline.