Joerd, can be used to download, merge and generate tiles from digital elevation data. These tiles can then be used in a variety of ways; for map display in Walkabout, in Valhalla's Skadi for elevation influenced routing. In keeping with the Norse mythological theme used by Valhalla, the jotunn/goddess Jörð was chosen as she is the personification of the Earth.

How do I pronounce it?

Jörð is pronounced:

• j = y as in english 'yellow'
• ö = ö as in german 'Göttin'
• r = r as in spanish 'pero'
• ð = th as in english 'they'

Which is close to "y-earthe". Many thanks to @baldur for lending us his voice.

Building

Build status:

Joerd is a Python command line tool using setuptools. To install on a Debian or Ubuntu system, you need to install its dependencies:

sudo apt-get install python-gdal python-bs4 python-numpy gdal-bin python-setuptools python-shapely

(NOTE: not sure if this works: I installed GDAL-2.0.1 manually here, but I don't think it really needs it.)

You can then install it (recommended in a virtualenv) by running:

python setup.py install

Using

Joerd installs as a command line library, and there are currently three commands:

• server starts up Joerd as a server listening for jobs on a queue. It is intended for use as part of a cluster to parallelise very large job runs.
• enqueue-downloads reads a config file and outputs a job to the queue for each source file needed by an output file in any configured region listed in the regions of the configuration file. This is intended for filling the queue for server to get work out of, but can also be used for local testing along with the fake queue type.
• enqueue-renders reads a config file and outputs a job to the queue for each output file in each region listed in the regions of the configuration file. This is intended for filling the queue for server to get work out of, but can also be used for local testing with the fake queue type.

There is also a script/generate.py program to generate a configuration with lots of little jobs all split up.

To run a command, type something like this:

joerd <command> --config config.example.yaml

Where <command> is one of the commands above (currently only process). The config has five sections:

• regions is a map of named sections, each with a bbox section having top, left, bottom and right coordinates. These describe the bounding box of the region. Data from the sources will be downloaded to cover that region, and outputs within it will be generated.
• outputs is a list of output plugins. Currently available:
  • skadi creates output in SRTMHGT format suitable for use in Skadi.
  • terrarium creates tiled output in GeoTIFF format.
• sources is a list of source plugins. Currently available:
  • etopo1 downloads data from ETOPO1, a 1 arc-minute global bathymetry and topology dataset.
  • gmted downloads data from GMTED, a global topology dataset at 30 or 15 arc-seconds.
  • srtm downloads data from SRTM, an almost-global 3 arc-second topology dataset.
• logging has a single section, config, which gives the location of a Python logging config file.
• cluster contains the queue configuration.
  • queue is used for all job communication, and can be either sqs or fake:
  • type should be either sqs to use SQS for communicating jobs, or fake to run jobs immediately (i.e: not queue them at all).
  • queue_name (sqs only) the name of the SQS queue to use.
• store is the store used to put output tiles after they have been rendered. The store should indicate a type and some extra configuration as sub-keys:
  • type should be either s3 to store files in Amazon S3, or file to store them on the local file system.
  • base_dir (file only) the filesystem path to use as a prefix for stored files.
  • bucket_name (s3 only) the name of the bucket to store into.
  • upload_config (s3 only) a dictionary of additional parameters to pass to the upload function.
• source_store is the store to download source files to when processing a download job, and retrieve them from when processing a render job. Note that all the source files needed by the render jobs must be present in the source store before the render jobs are run. Configuration is the same as for store.

Caveats

When using SRTM source HGT files, it's possible to run into this bug. The work-around given in the issue (export GDAL_SKIP=JPEG) appears to work.

License

Joerd uses the MIT License.

Contributing

We welcome contributions to Joerd. If you would like to report an issue, or even better fix an existing one, please use the Joerd issue tracker on GitHub.

Tests

We highly encourage running and updating the tests to make sure no regressions have been made. This can be done by running:

python setup.py test