Who made Sättningskartan? The data processing, web services and visualisations was performed by SkyGeo Netherlands and the theoretical background and methodology was developed by Delft Technical University. WSP has provided knowledge and data from the local conditions in Sweden and has contributed to shape the content of Sättningskartan. The initiative to Sättningskartan comes from both SkyGeo and WSP, to spread the knowledge of ground movements, InSAR and its capabilities to the public. It should be quick and easy to find settlement movements over the entire country.
What is the purpose of Sättningskartan? The purpose of Sättningskartan is to provide geodetical information of ground movements to the public.
What does the map show? The map and its data shows vertical displacement of measuring points on the ground, indicated by color from the average displacement rate for each point. By clicking a point, the detailed progress of that point over tie can be seen.
What techniques have been used to compute the deformations? Several techniques have been used to compute the deformations. Gravity measurments, GNSS- and InSAR-technology, as well as corrections for systematic effects such as land uplift.
What can I use the map for? Sättningskartan gives the user an overview of ground movements on the earth surface, on buildings and infrastructure etc. The color and placement of the measuring points are approximate. This means that they have been computed from raw data and models where several simplifications and generalisations have been performed. Due to this, they are displayed with an uncertainty, which can vary from point to point and between different measuring epochs. The map shows displacements with a large level of detail but requires a lot of knowledge and care to analyse and interpret. To be able to make a correct interpretation or analysis of the data, special knowledge and expertise within geodesy and the specific algorithms used to compute the data in the map is required, see also the disclaimer. It is important to realise that several different processing algorithms could be applied to the sama data set. In many cases, a change in processing methodology also gives a different result: more or less measuring points, higher or lower precisions, higher or lower confidence level and even a difference in displacement rates. Specific adaptions for various projects require a unique set of data and processing parameters.
How exact are the measurements? The measurements themselves have a relative precision in the millimeter range. The absolute height of each point is, with this method, obtained with a precision on meter-level and the horizontal position has a precision of 10-15 m. The InSAR technology is optimized for measuring relative displacements over time.
Depending on location, noise or other error effects could be found. Water surfaces provide the worst result (too much noise) and hard infrastructure provides the best result (low noise). At the data processing, the unstable or high noise measures are automatically removed, but this is a statistical process and is therefore never perfect. See also the disclaimer.
For who is Sättningskartan intended? Sättningskartan is intenden for as broad audience as possible, both professionals and other interested individuals or organisations with the need to know more about ground movements. The needs could be connected to themes such as mining, drought, life quality, aging infrastructure, energy, transport and safety etc.
Is the map free? Yes, the map is a free online web service fully accessible. The information is provided under CC BY-SA 4.0
Can I use the visualisations in Sättningskartan for my own purposes? Yes, with a clear and visible reference, see CC BY-SA 4.0. The aim of Sättningskartan is to be a reference for politicians, companies, students or private persons. Always enter “Source: Sättningskartan.se”, the year and other copyright information from the map, in your material.
Why is it important to know about ground movements? Settlements (or uplift) can lead to damage of infrastructure, buildings and land, which could be avoided and minimized through applying the right actions on the righ place in the right time. To analyse why a damage has occured can also be performed through historical analysis of the data on site.
Can I ask questions as a private person? The team behind Sättningskartan unfortunately does not have the capacity to answer private errands. Analysis of individual buildings or very small project areas require a specialized processing of data, using local conditions on site. WSP as experience within these type of projects. You are welcome with your question as a private person, but we cannot guarantee that we can help you.
How good is the precision in absolute position for the points? The placement of the measuring points are also estimates with varying precision. In general the measuring points are located within 10-15m from their true positions. Also consider the background material, such as aerial images, which also contains some uncertainty. In addition, tall construction tend to have a tilt in aerial images. A reprocessing of satellite data with fewer simplifications can improve the location precision to less than 1 meter.
Can I find out something about the reason for the displacements? Sättningskartan show estimated displacements of measuring points. The reason for the displacements can depend on many different processes. It is important when interpreting the data, to never draw conclusions strictly from this map. For that type of interpretations or analysis, it is required to use (I) experienced expertise within geodesy and the numerical algorithms used to produce the map, to eliminate the impacts of noise or errors. (II) If the reliability of the data has been determined, further interpretation and analysis can be performed by expertise within civil engineering, geology, mining etc.
Why are points shown only in the built environment and not in vegetated or agricultural areas? The radar satellite receives measuring points every square meter, but most areas on the ground are not suitable for estimating ground movements. To do this, the reflection characteristics of the surface must be comparable over time. This is not the case for most agricultural or vegetated areas, where crops or vegetation is growing, harvested and moving in the wind. Therefore, the quality of these points are not adequate and they have been removed.