pygeometa Tutorial
Overview
This tutorial provides a tour of pygeometa for both users and developers, and is aimed at getting you up and running quickly. Let's go!
For Users
Installation
You require Python 3 or greater to use pygeometa.
The easiest way to install pygeometa is using pip:
pip3 install pygeometa
This will install the latest stable release. If you are looking to work with pygeometa from source, see the For Developers section for more information.
Workflow
The basic pygeometa workflow is:
- Create a 'metadata control file' YAML file that contains metadata information
- Modify the sample.yml example
- pygeometa supports nesting MCFs together, allowing providing a single MCF for common metadata parameters (e.g. common contact information)
- Refer to the Metadata Control File Reference documentation
- Run pygeometa for the .yml file with a specified target metadata schema
Running
# show all subcommands
pygeometa
# show all supported schemas
pygeometa metadata schemas
# provide a basic sanity check/report on an MCF (Metadata Control File)
pygeometa metadata info path/to/file.yml
# generate an ISO 19139 document to stdout
pygeometa metadata generate path/to/file.yml --schema=iso19139
# generate an ISO 19139 document to disk
pygeometa metadata generate path/to/file.yml --schema=iso19139 --output=some_file.xml
# generate an ISO 19139 document to disk with debugging (ERROR, WARNING, INFO, DEBUG)
pygeometa metadata generate path/to/file.yml --schema=iso19139 --output=some_file.xml --verbosity=DEBUG # add verbose (ERROR, WARNING, INFO, DEBUG)
# use your own defined schema
pygeometa metadata generate path/to/file.yml --schema_local=/path/to/my-schema --output=some_file.xml # to file
# validate an MCF document
pygeometa validate path/to/file.yml
# import a metadata document to MCF
pygeometa metadata import path/to/file.xml --schema=iso19139
# transform from one metadata representation to another
pygeometa metadata transform path/to/file.xml --input-schema=iso19139 --output-schema=oarec-record
For Developers
Installation
pygeometa is best installed and used within a Python virtualenv.
Requirements
- Python 3 and above
- Python virtualenv package
Dependencies
Dependencies are listed in requirements.txt
. Dependencies
are automatically installed during pygeometa's installation.
Installing the Package from Source
python3 -m venv my-env
cd my-env
. bin/activate
git clone https://github.com/geopython/pygeometa.git
cd pygeometa
python3 setup.py build
python3 setup.py install
Using the API from Python
from pygeometa.core import read_mcf, render_j2_template
# read from disk
mcf_dict = read_mcf('/path/to/file.yml')
# read from string
mcf_dict = read_mcf(mcf_string)
# choose ISO 19139 output schema
from pygeometa.schemas.iso19139 import ISO19139OutputSchema
iso_os = ISO19139OutputSchema()
# default schema
xml_string = iso_os.write(mcf_dict)
# user-defined schema
xml_string = render_j2_template(mcf_dict, schema_local='/path/to/new-schema')
# write to disk
with open('output.xml', 'wb') as ff:
ff.write(xml_string)
Development
Setting up a Development Environment
Same as installing a package. Use a virtualenv. Also install developer requirements:
pip3 install -r requirements-dev.txt
Adding a Metadata Schema to the Core
Adding an output metadata schemas to pygeometa involves extending
pygeometa.schemas.base.BaseOutputSchema
and supporting the write
function to return a string of exported metadata content. If you are using
Jinja2 templates, see the next section. If you are using another means of
generating metadata (lxml, xml.etree, json, etc.), override the ABS write
class to emit a string using your tooling/workflow accordingly. See the
below sections for examples.
Once you have added your metadata schema, you need to register it with pygeometa's schema registry:
vi pygeometa/schemas/__init__.py
# edit the SCHEMAS dict with the metadata schema name and dotted path of class
Jinja2 templates
To add support for a new metadata schema using Jinja2 templates:
cp -r pygeometa/schemas/iso19139 pygeometa/schemas/new-schema
Then modify *.j2
files in the new pygeometa/schemas/new-schema
directory
to comply to new metadata schema.
Custom tooling
To add support for a new metadata schemas using other tooling/workflow:
mkdir pygeometa/schemas/foo
cp pygeometa/schemas/iso19139/__init__.py pygeometa/schemas/foo
vi pygeometa/schemas/foo/__init__.py
# update class name and super().__init__() function accordingly
Running Tests
# via distutils
python3 setup.py test
# manually
cd tests
python3 run_tests.py
Releasing
python3 setup.py sdist bdist_wheel --universal
twine upload dist/*
Code Conventions
Bugs and Issues
All bugs, enhancements and issues are managed on GitHub.
History
Started in 2009, pygeometa originated within an internal project called pygdm, which provided generic geospatial data management functions. pygdm (now end of life) was used for generating MSC/CMC geospatial metadata. pygeometa was pulled out of pygdm to focus on the core requirement of generating geospatial metadata within a real-time environment and automated workflows.
In 2015 pygeometa was made publically available in support of the Treasury Board Policy on Acceptable Network and Device Use.