cligj

cligj

.. image:: https://travis-ci.com/mapbox/cligj.svg :target: https://travis-ci.com/mapbox/cligj

.. image:: https://coveralls.io/repos/mapbox/cligj/badge.png?branch=master :target: https://coveralls.io/r/mapbox/cligj?branch=master

Common arguments and options for GeoJSON processing commands, using Click.

cligj is for Python developers who create command line interfaces for geospatial data. cligj allows you to quickly build consistent, well-tested and interoperable CLIs for handling GeoJSON.

Arguments

files_in_arg Multiple files

files_inout_arg Multiple files, last of which is an output file.

features_in_arg GeoJSON Features input which accepts multiple representations of GeoJSON features and returns the input data as an iterable of GeoJSON Feature-like dictionaries

Options

verbose_opt

quiet_opt

format_opt

JSON formatting options

``indent_opt``

``compact_opt``

Coordinate precision option

precision_opt

Geographic (default), projected, or Mercator switch

``projection_geographic_opt``

``projection_projected_opt``

``projection_mercator_opt``

Feature collection or feature sequence switch
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
``sequence_opt``

``use_rs_opt``

GeoJSON output mode option
~~~~~~~~~~~~~~~~~~~~~~~~~~
``geojson_type_collection_opt``

``geojson_type_feature_opt``

``def geojson_type_bbox_opt``

Example
-------

Here's an example of a command that writes out GeoJSON features as a collection
or, optionally, a sequence of individual features. Since most software that
reads and writes GeoJSON expects a text containing a single feature collection,
that's the default, and a LF-delimited sequence of texts containing one GeoJSON
feature each is a feature that is turned on using the ``--sequence`` option.
To write sequences of feature texts that conform to the `GeoJSON Text Sequences
standard <https://tools.ietf.org/html/rfc8142>`__ (and might contain
pretty-printed JSON) with the ASCII Record Separator (0x1e) as a delimiter, use
the ``--rs`` option

.. warning:: Future change warning
   GeoJSON sequences (`--sequence`), not collections (`--no-sequence`), will be
   the default in version 1.0.0.


.. code-block:: python

    import click
    import cligj
    import json

    def process_features(features):
        for feature in features:
            # TODO process feature here
            yield feature

    @click.command()
    @cligj.features_in_arg
    @cligj.sequence_opt
    @cligj.use_rs_opt
    def pass_features(features, sequence, use_rs):
        if sequence:
            for feature in process_features(features):
                if use_rs:
                    click.echo(u'\x1e', nl=False)
                click.echo(json.dumps(feature))
        else:
            click.echo(json.dumps(
                {'type': 'FeatureCollection',
                 'features': list(process_features(features))}))

On the command line, the generated help text explains the usage

.. code-block:: console

    Usage: pass_features [OPTIONS] FEATURES...

    Options:
    --sequence / --no-sequence  Write a LF-delimited sequence of texts
                                containing individual objects or write a single
                                JSON text containing a feature collection object
                                (the default).
    --rs / --no-rs              Use RS (0x1E) as a prefix for individual texts
                                in a sequence as per http://tools.ietf.org/html
                                /draft-ietf-json-text-sequence-13 (default is
                                False).
    --help                      Show this message and exit.

And can be used like this

.. code-block:: console

    $ cat data.geojson
    {'type': 'FeatureCollection', 'features': [{'type': 'Feature', 'id': '1'}, {'type': 'Feature', 'id': '2'}]}

    $ pass_features data.geojson
    {'type': 'FeatureCollection', 'features': [{'type': 'Feature', 'id': '1'}, {'type': 'Feature', 'id': '2'}]}

    $ cat data.geojson | pass_features
    {'type': 'FeatureCollection', 'features': [{'type': 'Feature', 'id': '1'}, {'type': 'Feature', 'id': '2'}]}

    $ cat data.geojson | pass_features --sequence
    {'type': 'Feature', 'id': '1'}
    {'type': 'Feature', 'id': '2'}

    $ cat data.geojson | pass_features --sequence --rs
    ^^{'type': 'Feature', 'id': '1'}
    ^^{'type': 'Feature', 'id': '2'}

In this example, ``^^`` represents 0x1e.