Announcing TerraSTREAM 0.5
We are happy to announce the release of the fourth beta of TerraSTREAM. TerraSTREAM performs flow modeling and terrain analysis tasks on very large digital elevation models and works equally well on TIN and grid DEMs. 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. TerraSTREAM 0.5 comes with direct MapInfo and ArcGIS 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 using scripting. For more information about this release and for contact information, visit http://madalgo.au.dk/Trac-TerraSTREAM/.
This TerraSTREAM release contains the following major features:
- Hydrologically Condition DEMs
- Prepare a DEM for flow analysis by removing "insignificant" sink(pits) by flooding them. A sink is insignificant if its height is smaller than some user specified threshold.
- Compute Flow Routings
- Compute flow directions for each data point in a DEM. This can be done using either SFD or MFD routing and with sophisticated flat routing techniques.
- Compute Flow Accumulations
- Accumulate amounts of, e.g., water on a DEM along flow paths.
- Construct a Watershed Hierarchy
- Construct a Pfafstetter labelling of the watersheds of a DEM.
We would like to thank all of our testers, we have received a great amount of valuable feedback. If you are interested in TerraSTREAM development and discussions we encurage you to subscribe to our (low volume) mailing list here: http://mailman.nfit.au.dk/mailman/listinfo/madalgo.au.dk-terrastream-devel. Future releases will be announced to that mailing list.
TerraSTREAM can be downloaded from http://madalgo.au.dk/Trac-TerraSTREAM/wiki/Download. We have prepared builds for Windows, Mac OS X, and some flavors of Linux.
Changes between 0.4 and 0.5
There have been a very large amount of changes to TerraSTREAM in the past 6 months since the release of version 0.4. Some of the highlights of this new release include:
- In version 0.5 the stability of TerraSTREAM has increased significantly, especially on Windows. Previous releases had problems when the memory limit was set too high, but this has hen fixed in TerraSTREAM 0.5 and the default memory limit has been raised to 1 gigabyte (ticket:43).
- All TerraSTREAM modules now support reading and and writing raster mosaics (ticket:87). Raster mosaics consist of many individual grid tiles which can be combined to form one large raster.
- TerraSTREAM now ships with a utility that can translate between TPIE files (TerraSTREAMs internal format) and regular raster formats. This tool can also be used to convert raster mosaics to a single raster or split existing rasters into multiple tiles.
- Flat routing now gives up if the flat area is too big to fit in memory. Thus, flow directions on a terrain with very large flat areas can be successfully computed, although big flat areas themselves are unfortunately ignored. In previous versions of TerraSTREAM the routing process would simply crash on large flat areas (ticket:23).
- TerraSTREAM now supports three different routing models on grids. SFD (D-8), MDF and Flux Decomposition (D-infinity) (ticket:97). Furthermore bugs in the existing SFD and MFD routing models were fixed (ticket:110), routings computing with old versions of TerraSTREAM are incorrect.
The full list of closed tickets are:
- Problems reading grid metadata in EPSG-format on Windows
- Memory allocation bug in Soille routing TS-0.2
- TPIE Crash at ~900megs of memory.
- GDAL driver and cell types
- Generate RPMs and DEBs
- grass tpie HAVE_UNISTD_H conflicts
- Set default value of grid-type parameter to GDAL on windows?
- "On windows tmppath variable contains 2 versions of the path ""."" and is printed as "" .\|.\."""
- Memory allocation error in Conditioning
- Output direction grid output missing from ArcGIS Toolbox
- slope gradient problem
- Flexibility with output formats
- Read Raster Mosaics
- Raster Driver in MapInfo? Extensions
- Intersecting Contours
- Sign annoyance in flow routing output
- Flooding is broken
- New routing method: Flux Decomposition
- nodata type sweep uses too much memory
- Memory leak in nodata area handling
- Mfd direction computer leaves out directions
- GDAL writer does not write nodata value to output raster
- Reading and Writing LAS Files
- Incorrect SFD routing
- Messed up progress bars
- merge ts-calc-persistence and ts-condition in modules/standalone?
- --skip-island parameters missing from guis
- Crash in calc-persistence
Changes before 0.4
See the release announcement for 0.4.
Known Bugs and Issues
- The frontends provided for TerraSTREAM 0.5 do not work on TINs. Even though the core components are available for TINs we have not yet developed user-friendly front ends for these since we have not determined what kind of TIN file formats should be supported. If you would like to use TerraSTREAM on your TINs please give use information on the type of file format you use by replying to ticket:8.
TerraSTREAM 0.5 is available from http://madalgo.au.dk/Trac-TerraSTREAM/. Note that TerraSTREAM is beta grade software. Bug reports and feature requests are very welcome and will hopefully result in more stable and capable future versions of the software. Please attach the output from the command to the bug report, if possible.
The TerraSTREAM Developers - January, 2009.