A study area covering parts of Northern Jutland was analysed using relevant Sentinel 1 and 2 satellite imagery from 2017.

The temporal resolution of Sentinel-1 is high, and it therefore has the advantage of providing large amounts of data throughout the year. However, it is limited in its spatial resolution which makes the classification of relatively small objects difficult e.g. small lakes, since they do not show on the images.

Sentinel-2, on the other hand, has the advantage of having a significantly better spatial resolution, which enables the classification of small lakes. Here, the limitation is that clouds and shadows limit the temporal resolution.

Combining data from the two satellites, would therefore give a better data coverage.

We found that a relatively large portion of the mapped lakes in the GeoDenmark dataset, from a Sentinel-based point of view, either cannot be described as lakes or may be deviating from the existing categories.

The results of this study indicates that there are good prospects in using the Sentinel-based data sources and methods for a nationwide automated classification and quality assurance of topographical maps, such as the mapped lakes in the GeoDenmark data set.

In this study, we focused on previously mapped lakes in the GeoDenmark data set, but it is expected that the same method could be used to map lakes that do not already exist in the dataset.

Based on a limited further investigation of the methods used, it is estimated that a nationwide screening of all lakes in Denmark, approx. 180.000 in total, could be automatically categorized and figure in the GeoDenmark dataset for lakes.