The Legendary Island of Avalon (image credit)
The GeoTrellis team is very excited to announce the availability of GeoTrellis 0.9 (codename “Avalon”), a significant new release that is a big step forward towards our goal of a general purpose, high performance raster geoprocessing library and runtime designed to perform and scale for the web.
First of all, we’ve significantly revised the documentation site — http://geotrellis.io/. Props to Rob Emanuele for the new site and the Azavea design team for revised styling. The new site includes both case studies and some samples we’ve developed since the 0.8 release. There is a full set of release notes available, but here are some highlights:
- API Refactor: We’re moving away from requiring users to manually create operations and pass in rasters as arguments, and instead having objects called ‘DataSources’ that represent the source of data, with the operations to transform or combine that data as methods on those objects. These methods are not stateful, they return new DataSources per method call. Similar to the ‘Future’-like model of Operations, transformations on a DataSource are not actually run until the server is told to ‘run’ the source, either explicitly or through a method call on DataSource and an implicit server parameter. Special thanks to joshmarcus for his vision of this API change and all the work he put into making it happen. This API change also means that any code that currently runs on an 0.8 release will probably be very broken. The ability to create and run Op[T]’s is still there, but some of the functionality, especially dealing with parallelizing over tiles, was stripped from them. Let us know on the mailing list or in #geotrellis on freenode IRC if you’re upgrading and we’ll lend a hand with the transition
- File I/O: Reading ARGs from disk has been sped up, and in some cases, you’ll find improvements of an order of magnitude or more.
- Spray.io: Replaced Jetty with Spray.io, a fast HTTP server for Akka Actors
- Tile operation improvements: Running multiple operations over tiled data has been greatly improved. For example, if you were to multiply a raster by an integer, add the result to another tiled raster, and then run a zonal summary (such as taking the mean of values within a polygon) on that result, GeoTrellis 0.8 would unnecessarily reduce to a whole raster in memory between the different transformations (see issue #517). In 0.9, you’ll get the desired behavior, where the multiplication, addition, and zonal summary all all done in parallel per tile, before the final zonal summary result is created from the reduction of the tile zonal summary results.
- Clustering improvements: We took several steps to make it easier to distribute operations over a cluster using Akka clustering. There’s a .distribute call on DataSource which will distribute all of the operations of the DataSource’s elements across the cluster, based on the configuration.
- Macros: A new geotrellis-macros project was created to deal with issue #624, based on the discussion of #324. This includes macros for checking whether a value is or isn’t NoData, independent of what type that data is. And these checks are inlined through macro magic, so there’s no performance hit for the nicer syntax.
- Revised Operations: Added double support to Focal Standard Deviation, Focal Min, Focal Max, Focal Sum operations; added 8-neighbor connectivity to RegionGroup;
- New Operations: Ordinary Kriging Interpolation, Hydrology operations (Fill, Flow Accumulations, Flow Direction), IDW Interpolation
Version 0.10 Plans
We’re hard at work on a GeoTrellis 0.10. The major plans for this release include:
- Github: http://github.com/geotrellis/geotrellis
- Maven repository: https://oss.sonatype.org/content/repositories/releases/
- Issue tracker for 0.10: https://github.com/geotrellis/geotrellis/issues?milestone=6&page=1&state=open
- Mailing list: https://groups.google.com/group/geotrellis-user
- IRC: #geotrellis on freenode
GeoTrellis is released under the Apache2 license.