waterbody verification map
In this map you can see the points where the waterbody flattening of DEMs has lead to a more than 100m change (more in case of the lower zoom levels) in elevation based on Openstreetmap waterbody data. Points at the coastline are shown in green, inland waterbodies in blue. A click on the point opens further information and links concerning this data point.
The most frequent causes of these errors despite simple tolerances and inaccuracies in the waterbody data are the misinterpretation of shadows in aerial and satellite images as water. Apart from that artificial reservoirs with varying water levels and newly built ones are a possible cause. In very steep shoreline sections inaccuracies of the elevation model can also be the sole reason for an error displayed.
The error lists this map is based on and the program to generate them can also be downloaded.