What's New – National hydrological corrections and updated local data for Finland

Jul 4, 2021

We have released a significant upgrade to the Finnish model in SCALGO Live. We have included new elevation data for Helsinki and Lahti, and we have produced hydrological corrections for the entire country which we have used in the analysis.

Hydrological corrections

Hydrological corrections make it possible to model water that flows through supposed obstacles in the elevation model that actually allow water to flow in reality. For instance, when a stream crosses a road under a bridge, the elevation model could make it look like there is a blockade since the space under the bridge is not represented.

Hydrological corrections shown in green for an area around a freeway east of Nupuri, Finland.

We treat hydrological corrections as logical structures that allow water to flow from one end to the other, they typically do not alter the elevation model itself. Thus, waterways can cross in SCALGO Live — a very powerful feature. For instance, water can flow on top of a bridge in the direction of the road, and at the same time a river can cross the road under the bridge in a different direction. Hydrological corrections have infinite transport capacity, we do not model flooding from e.g. under-dimensioned culverts and bridge openings.

When you create a workspace, the hydrological corrections are included automatically, unless you create a model from a custom DEM or through the "Existing model" feature — in that case you can choose to import corrections directly from the workspace itself.

Updated elevation data for Helsinki and Lahti

For the areas around Helsinki and Lahti, we now use elevation models with a horizontal resolution of 1 meter made available for SCALGO Live users by the respective municipalities. This provides a substantial lift in data quality for users in those areas. In order to incorporate these models, we now represent the whole country in a 1 m model instead of a 2 m model. This also holds for workspaces created from this point onwards.

The elevation model for Finland in the previous 2 m version and the new 1 m model around the Ursa Observatory in Helsinki.

You can see the coverage of the new models in the sources layer in SCALGO Live:

The various sources of elevation data in Finland. The purple and pink areas in the south indicate the coverage area of the new Lahti and Helsinki models. For more information on the sources of the elevation data in Finland, please consult the documentation.