What's new – Hydrological corrections and new data in Sweden

Apr 1, 2020

We have updated SCALGO Live in Sweden with new elevation data and buildings from Lantmäteriet. While updating the elevation data we have introduced more than 1 million hydrological corrections that improve the description of flow paths through culverts or under bridges across the country. We also added a range of new data sets that have been requested by users. This is our biggest update for Sweden yet. We hope you enjoy it. Read more below or in the manual.

Hydrological corrections

Bridges, culverts and other structures, where water is transported below the surface of the terrain, are not represented in a traditional digital elevation model. When analysing elevation models, bridges therefore act as dams creating spurious depressions and missing culverts fail to transport water creating erroneous flow paths. Hydrological corrections supplement the elevation model by representing the subsurface flow paths of culverts and bridges. This update of SCALGO Live includes a new nationwide hydrological correction data set that SCALGO has created using advanced algorithms and Machine Learning techniques together with Lantmäteriet's nationwide elevation model and data about rivers and streams.

The river Viskan goes through Borås and some buildings intersect it. Left: Before hydrological correction this caused major flooding in the flash flood map in the downtown area. Right: Two hydrological corrections (green) allow Viskan to flow freely, removing the depression caused by the obstructing buildings.

Conservative corrections

The conservative corrections have been generated at locations where streams and rivers intersect railroads, roads, dams, weirs, or buildings, as well as invisible river sections where the river e.g. runs through a longer covered/piped area. The river network used for generating the corrections comes from Lantmäteriet's Hydrografi Nedladdning and the new corrections are therefore reliable up to the standard of Hydrografi Nedladdning. These corrections are automatically included in new workspaces and are also used in the national analysis available in SCALGO Live.

Comprehensive corrections

We have also developed a new Machine Learning technique that predicts where hydrological corrections exist with high probability. The result is a nationwide set of suggested corrections with an unprecedented coverage. They are not automatically included in the national analysis or workspaces, they are suggestions that can be imported into a workspace on request and checked by the user. We believe this has the potential to save a lot of time when setting up a new workspace by avoiding the time consuming task of manually creating all hydrological corrections.

Examples of hydrological corrections shown with backgrounds of orthophoto and elevation model. Top row: Conservative correction showing a culvert under a bigger road. Bottom row: Comprehensive correction suggested for a culvert under a tractor path between fields.

New data sets

Fastighetsindelning Visning

The cadastral map from Lantmäteriet has been added. The data set is provided as WMS, meaning that changes to cadastral borders are incorporated on a daily basis.

Ortofoto Visning

The latest orthophoto products from Lantmäteriet have been added. The available orthophoto resolutions are now 16 cm, 25 cm, 40 cm and 50 cm. Orthophotos will be served as WMS, meaning that changes and updates of orthophotos are incorporated on a daily basis.

Hydrografi Nedladdning

The most highly detailed data set of the Swedish river network ever produced. The data set contains a national coverage of all streams, standing water bodies, wetlands, dams and more in a scale of 1:25 000. It is available for use in SCALGO Live and for download.

GE.Jordarter 1:25 000-1:100 000

SGU's Jordarter 1:25 000 - 1:100 000 has also been made available as an INSPIRE data set. We have collected and organized the data into one unified national data set available for use in SCALGO Live and for download.

Example of Fastighetsindelning Visning shown in SCALGO Live together with the Flash Flood map.