Visualisation and analysis of multi-resolution raster geodatasets in the cloud

Abstract. Raster geodatasets are an important data source for map-related web applications. However, existing differences in how those datasets are georeferenced, formatted and made available complicate their integration for analysis and visualisation purposes. Furthermore, the inconsistent cell resolutions make it difficult to perform efficient and reliable display of the datasets over a range of scales. In particular, it is challenging to achieve satisfactory user experience in visual exploration of interactive analysis operations carried out on these datasets.

Dataset harmonisation carried out as a pre-processing procedure seems to be necessary for resolving the raster geodata inconsistency challenge. After the pre-processing step, the harmonized datasets have to be stored into an easily accessible data storage, preferably in close connection with the computing platform where the analysis operations are to be performed.

Multidimensional datacube has emerged as a conceptual framework for organising a repository of harmonised raster geodatasets. Satellite images have so far been the most popular geospatial application area for datacubes. The set of dimensions of such geodatacube typically consist of two or three coordinate axes, time, and the content theme. While being ingested into the datacube, the involved datasets are brought into a common georeferencing frame, series of cell resolutions, and storage format. The selected harmonised resolution levels can actually be seen as a set of individual geodatacubes.

An initiative has launched in Finland to build a harmonised multi-resolution geodatacube, called GeoCubes Finland, containing some of the most important national geodatasets. The datasets currently incorporated into the geodatacube include digital elevation models together with land cover, superficial deposit, forest inventory and administrative unit datasets. GeoCubes Finland is being built as part of the Finnish Open Geospatial Information Infrastructure for Research (oGIIR) programme, aimed at developing the geospatial research infrastructure of the country. The data storage and the related computing facilities have been implemented on a cloud service platform provided by CSC - IT Center for Science that serves Finnish universities and research institutes.