Wednesday, April 01, 2020

Meandering Rivers

The Guardian has assembled a collection of beautiful mapped visualizations which use elevation data to reveal some of the normally hidden details in river systems around the world. The maps show elevation values using color intensity to highlight rivers, their tributaries and to reveal their historical paths.

Each of the rivers in the collection includes a slide control which allows you to switch between a satellite view of the river and a view which uses elevation data to reveal features which are normally hidden by vegetation in the satellite view. The maps in Show with the flow: elevation maps reveal world rivers were created by Esri. In each of the maps the darker colors show the areas with the lowest elevations.

Esri's maps remind me of Harold Fisk's meander river maps. In 1944 Harold Fisk published a series of beautiful looking maps of the Mississippi River. In his 'Geological Investigation of the Alluvial Valley of the Lower Mississippi River', commissioned by the Army Corp of Engineers, Fisk not only mapped the flow of the Mississippi but also tried to represent how the river's course has meandered and changed over time.

Fisk's maps use a number of different colors to show the different courses of the river over the centuries. You can view static images of all fifteen of Fisk's maps for the Army Corp of Engineers on this radicalcartography post.

Some of the Army Corp of Engineers' later meander maps of the Mississippi River can also be viewed on Meiotic's Meander Maps. Meiotic has geo-referenced a few of the Army Corp's maps and placed them on top of modern maps and aerial imagery of the river's course. These maps include a slider control which allow you to compare the Army Corp's original maps with a modern map of the river.

Somebits has also geo-referenced all 15 of Fisk's original maps. The 1944 Map Of Former Courses of the Mississippi stitches all 15 maps together. Unfortunately the modern aerial imagery seems to be broken on this interactive map. However you can still compare Fisk's map to a terrain map of the Mississippi and you can use the interactive map controls to zoom-in and study Fisk's beautiful maps in loving detail.

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