Welcome to the TerraSTREAM Project
During the last couple of years the limited TerraSTREAM test releases have been increasingly popular and are now used by more than 50 organizations from every continent (except Antarctica) to handle the large data sets available to modern GIS users. In order to take the technology to the next level and to provide users with continuing professional service and support, the development of the TerraSTREAM software has been taken over by SCALGO.
TerraSTREAM is a series of libraries and front-ends for these libraries that allow the user to perform a series of computational tasks on very large digital elevation models, represented either as a TIN or a GRID. The algorithms used in the libraries have provable efficient performance in the worst case, even on very large terrains that do not fit in the main memory of the computer. The project is partially supported by a NABIIT grant from the Danish Strategic Research Council, a grant from the US Army Research Office for the STREAM project, a Ole Roemer Scholarship from the Danish National Science Research Council and by the Danish National Research Foundation.
TerraSTREAM comes with direct MapINFO and ArcGIS 9.2 support as well as a simple standalone graphical user interface and powerful command line tools that can be used alone or integrated into most GIS environments by scripting.
Subscribe to our low-volume mailing list here: http://mailman.nfit.au.dk/mailman/listinfo/madalgo.au.dk-terrastream-devel.
- March 15: 2009
- This video show how TerraSTREAM can be used to compute flood maps on a national scale (note that flood map computation is currently not included in the test releases).
- March 12, 2009
- TerraSTREAM 0.5.1 has been released: Release Announcement for 0.5. This release fixes an issue in the mosaic reader.
- January 26, 2009
- TerraSTREAM developers are attending the International LIDAR Mapping Forum. We would love to say hi to our users, contact Thomas Mølhave if you want to meet up.
- January 22, 2009
- TerraSTREAM 0.5 has been released: Release Announcement.
- January 8, 2009
- We are currently busy preparing TerraSTREAM 0.5 for release in late January. A lot of work has been done since the 0.4 release in August and users can expect a more stable terrastream with a number of new features.
- August 8, 2008
- TerraSTREAM 0.4 has been released: Release Announcement.
- August 7, 2008
- New website design launched.
- March 30, 2008
- TerraSTREAM 0.3.1 has been released: Release Announcement for 0.3, Users Guide. This release fixes some performance issues in conditioning found in 0.3.
- March 29, 2008
- TerraSTREAM 0.3 has been released: Release Announcement, Users Guide.
- February 1, 2008
- TerraSTREAM 0.2 has been released: Release Announcement, Users Guide.
- March 7, 2007
- TerraSTREAM 0.1 has been released.
TerraSTREAM is developed as a series of libraries and a set of front-ends using those libraries. Most components work on both TIN and grid DEMs. Many of the core features of TerraSTREAM are described in the paper TerraStream: from elevation data to watershed hierarchies. There is also an Users Guide available.
The primary features of TerraSTREAM are:
- DEM Construction
- Computes a digital elevation model (DEM) from a point cloud typically gathered using LIDAR. TerraSTREAM can construct both TINs and grids.
- DEM Topological Conditioning
- The topological conditioning module simplifies digital elevation models by first identifying and then removing insignificant geographical features. Here, significance are the feature's height, area and volume or any combination of these and a feature is insignificant if its significance is smaller than some threshold specified by the user.
- Flow Routing
- Compute flow directions for each data point in a DEM. The routing models supported are
steepest-flow-descent Distributes flow to the steepest downslope neighbor
multiple-flow-directions Distibutes flow to all downslope neighbors
flux decomposition Distributes flor two to downslope neighbors according to the aspect direction
- Flow Accumulation
- Accumulate amounts of, e.g., water on a DEM along flow paths as computed by the flow routing module.
- Flood Simulation
- The flood simulation module can computer two different things, both related to flood risk assesment.
Flood Mask: Given a height value 'x', the flood simulation computes a mask of the cells that are flooded if the water lever were rased 'x' units.
General: Transforms a DEM to a new DEM where the height of each cell in the produced DEM is the miniumum height that the water level needs to be raised to in order for that particular cell to flood. In both cases, dikes and other features are taken into account such that in-land depressions sorrounded by dikes/hills are not flooded before the dykes themselves.
- Contour Map Computation
- Computes the contour map of a terrain. It uses the topological conditioning module internally to intelligently remove "insignificant" contour lines based on the area, volume and height of the geographical feature that it represents.
- Raster Quality Assessment
- This raster quality modules takes a raster and point cloud and computes how far the center of each raster cell is from the closest point in the point cloud. By colouring the output by intensity (length) it is easy to spot areas of the grid where there are no points close. If the point cloud used is the same used for generating the input raster this can be used for quality control of the point cloud, the classification algorithm used and the produced raster.
- Watershed Hierarchy Construction
- Construct a Pfafstetter labelling of the watersheds of a DEM.
- LS-Factor Computation
- Compute the LS-factor of a grid DEM. The LS-factor is an aggregate of the slope length factor(L) and the slope steepness factor(S). The length and slope factors estimate the effects of slope length and steepness on erosion.
- Format Flexibility
- TerraSTREAM support reading and writing mosaic grids in many common formats and supports the LAS file format for point data.
The components are designed such that the input to one component generally is the output of another component, so that a pipeline of components is provided.
The core of TerraSTREAM is independent on any particular front-end system and new front-ends can be added with ease. Currently, the following front-ends are supplied with specialized extensions
There's also a set of command line tools with an extensive set of parameters as well as a simple standalone gui that can be used for simpler tasks.
- Please go here to create a bug report or request a feature.
- Information about the [TerraChurners], which are the lab machines in Aarhus and Durham.
Comments or questions, contact Thomas Mølhave