fiona 1.0.1

Fiona reads and writes spatial data files

=================================================================
Fiona: OGR's neat, nimble, no-nonsense API for Python programmers
=================================================================

**Fiona** provides uncomplicated Python interfaces to functions in OGR_,
the best open source C/C++ library for reading and writing geographic vector
data.

Fiona is designed to be simple and dependable. It focuses on reading and
writing data in standard Python IO style, and relies upon familiar Python types
and protocols such as files, dictionaries, mappings, and iterators instead of
classes specific to OGR. Fiona can read and write real-world data using
multi-layered GIS formats and zipped virtual file systems and integrates
readily with other Python GIS packages such as pyproj_, Rtree_, and Shapely_.

For more details, see:

* Fiona `home page <https://github.com/Toblerity/Fiona>`__
* Fiona `docs and manual <http://toblerity.github.com/fiona/>`__
* Fiona `examples <https://github.com/Toblerity/Fiona/tree/master/examples>`__

Dependencies
============

Fiona requires Python 2.6, 2.7, or 3.3 and GDAL/OGR 1.8+. To build from
a source distribution or repository copy you will need a C compiler and GDAL
and Python development headers and libraries (libgdal1-dev for Debian/Ubuntu,
gdal-dev for CentOS/Fedora).

The popular `Kyngchaos GDAL frameworks
<http://www.kyngchaos.com/software/frameworks#gdal_complete>`__ will satisfy
the dependency for OS X. Fiona's author uses Homebrew (``brew install gdal``)
on OS X.

While there are no official binary distributions or Windows support at this
time, you can find Windows installers at
http://www.lfd.uci.edu/%7Egohlke/pythonlibs/#fiona.


Installation
============

Requirements
------------

Fiona depends on the modules ``six`` and ``argparse``. The latter is standard
in Python 2.7+. Easy_install and pip will fetch these requirements for you, but
users installing Fiona from a Windows installer must get them separately.

Unix-like systems
-----------------

Assuming you're using a virtualenv (if not, skip to the 4th command) and
GDAL/OGR libraries, headers, and `gdal-config`_ program are installed to well
known locations on your system via your system's package manager (``brew
install gdal`` using Homebrew on OS X), installation is this simple::

$ mkdir fiona_env
$ virtualenv fiona_env
$ source fiona_env/bin/activate
(fiona_env)$ pip install Fiona

If gdal-config is not available or if GDAL/OGR headers and libs aren't
installed to a well known location, you must set include dirs, library dirs,
and libraries options via the setup.cfg file or setup command line as shown
below (using ``git``)::

(fiona_env)$ git clone git://github.com/Toblerity/Fiona.git
(fiona_env)$ cd Fiona
(fiona_env)$ python setup.py build_ext -I/path/to/gdal/include -L/path/to/gdal/lib -lgdal install

Windows
-------

Binary installers are available at
http://www.lfd.uci.edu/~gohlke/pythonlibs/#fiona and coming eventually to PyPI.

Usage
=====

Collections
-----------

Records are read from and written to ``file``-like `Collection` objects
returned from the ``fiona.open()`` function. Records are mappings modeled on
the GeoJSON format. They don't have any spatial methods of their own, so if you
want to do anything fancy with them you will probably need Shapely or something
like it. Here is an example of using Fiona to read some records from one data
file, change their geometry attributes, and write them to a new data file.

.. sourcecode:: python

import fiona

# Open a file for reading. We'll call this the "source."
with fiona.open('docs/data/test_uk.shp') as source:

# The file we'll write to, the "sink", must be initialized with a
# coordinate system, a format driver name, and a record schema.
# We can get initial values from the open collection's ``meta``
# property and then modify them as desired.
meta = source.meta
meta['schema']['geometry'] = 'Point'

# Open an output file, using the same format driver and coordinate
# reference system as the source. The ``meta`` mapping fills in
# the keyword parameters of fiona.open().
with fiona.open('test_write.shp', 'w', **meta) as sink:

# Process only the records intersecting a box.
for f in source.filter(bbox=(-5.0, 55.0, 0.0, 60.0)):

# Get a point on the boundary of the record's geometry.
f['geometry'] = {
'type': 'Point',
'coordinates': f['geometry']['coordinates'][0][0]}

# Write the record out.
sink.write(f)

# The sink's contents are flushed to disk and the file is closed
# when its ``with`` block ends. This effectively executes
# ``sink.flush(); sink.close()``.

Reading Multilayer data
-----------------------

Collections can also be made from single layers within multilayer files or
directories of data. The target layer is specified by name or by its integer
index within the file or directory. The ``fiona.listlayers()`` function
provides an index ordered list of layer names.

.. sourcecode:: python

for layername in fiona.listlayers('docs/data'):
with fiona.open('docs/data', layer=layername) as c:
print(layername, len(c))

# Output:
# test_uk 48

Layer can also be specified by index. In this case, ``layer=0`` and
``layer='test_uk'`` specify the same layer in the data file or directory.

.. sourcecode:: python

for i, layername in enumerate(fiona.listlayers('docs/data')):
with fiona.open('docs/data', layer=i) as c:
print(i, layername, len(c))

# Output:
# 0 test_uk 48

Writing Multilayer data
-----------------------

Multilayer data can be written as well. Layers must be specified by name when
writing.

.. sourcecode:: python

with open('docs/data/test_uk.shp') as c:
meta = c.meta
f = next(c)

with fiona.open('/tmp/foo', 'w', layer='bar', **meta) as c:
c.write(f)

print(fiona.listlayers('/tmp/foo'))
# Output: ['bar']

with fiona.open('/tmp/foo', layer='bar') as c:
print(len(c))
f = next(c)
print(f['geometry']['type'])
print(f['properties'])

# Output:
# 1
# Polygon
# {'FIPS_CNTRY': 'UK', 'POP_CNTRY': 60270708.0, 'CAT': 232.0,
# 'AREA': 244820.0, 'CNTRY_NAME': 'United Kingdom'}

A view of the /tmp/foo directory will confirm the creation of the new files.

.. sourcecode:: console

$ ls /tmp/foo
bar.cpg bar.dbf bar.prj bar.shp bar.shx

Collections from archives and virtual file systems
--------------------------------------------------

Zip and Tar archives can be treated as virtual filesystems and Collections can
be made from paths and layers within them. In other words, Fiona lets you read
and write zipped Shapefiles.

.. sourcecode:: python

for i, layername in enumerate(
fiona.listlayers(
'/',
vfs='zip://docs/data/test_uk.zip')):
with fiona.open(
'/',
vfs='zip://docs/data/test_uk.zip',
layer=i) as c:
print(i, layername, len(c))

# Output:
# 0 test_uk 48

Dumpgj
======

Fiona installs a script named "dumpgj". It converts files to GeoJSON with
JSON-LD context as an option.

::

$ dumpgj --help
usage: dumpgj [-h] [-d] [-n N] [--compact] [--encoding ENC]
[--record-buffered] [--ignore-errors] [--use-ld-context]
[--add-ld-context-item TERM=URI]
infile [outfile]

Serialize a file's records or description to GeoJSON

positional arguments:
infile input file name
outfile output file name, defaults to stdout if omitted

optional arguments:
-h, --help show this help message and exit
-d, --description serialize file's data description (schema) only
-n N, --indent N indentation level in N number of chars
--compact use compact separators (',', ':')
--encoding ENC Specify encoding of the input file
--record-buffered Economical buffering of writes at record, not
collection (default), level
--ignore-errors log errors but do not stop serialization
--use-ld-context add a JSON-LD context to JSON output
--add-ld-context-item TERM=URI
map a term to a URI and add it to the output's JSON LD
context

Development and testing
=======================

Building from the source requires Cython. Tests require Nose. If the GDAL/OGR
libraries, headers, and `gdal-config`_ program are installed to well known
locations on your system (via your system's package manager), you can do this::

(fiona_env)$ git clone git://github.com/Toblerity/Fiona.git
(fiona_env)$ cd Fiona
(fiona_env)$ python setup.py develop
(fiona_env)$ nosetests

If you have a non-standard environment, you'll need to specify the include and
lib dirs and GDAL library on the command line::

(fiona_env)$ python setup.py build_ext -I/path/to/gdal/include -L/path/to/gdal/lib -lgdal develop
(fiona_env)$ nosetests

.. _OGR: http://www.gdal.org/ogr
.. _pyproj: http://pypi.python.org/pypi/pyproj/
.. _Rtree: http://pypi.python.org/pypi/Rtree/
.. _Shapely: http://pypi.python.org/pypi/Shapely/
.. _gdal-config: http://www.gdal.org/gdal-config.html


Changes
=======

1.0.1 (2013-08-16)
------------------
- Allow ordering of written fields and preservation of field order when
reading (#57).

1.0 (2013-07-30)
-----------------
- Add prop_type() function.
- Allow UTF-8 encoded paths for Python 2 (#51). For Python 3, paths must
always be str, never bytes.
- Remove encoding from collection.meta, it's a file creation option only.
- Support for linking GDAL frameworks (#54).

0.16.1 (2013-07-02)
-------------------
- Add listlayers, open, prop_width to __init__py:__all__.
- Reset reading of OGR layer whenever we ask for a collection iterator (#49).

0.16 (2013-06-24)
-----------------
- Add support for writing layers to multi-layer files.
- Add tests to reach 100% Python code coverage.

0.15 (2013-06-06)
-----------------
- Get and set numeric field widths (#42).
- Add support for multi-layer data sources (#17).
- Add support for zip and tar virtual filesystems (#45).
- Add listlayers() function.
- Add GeoJSON to list of supported formats (#47).
- Allow selection of layers by index or name.

0.14 (2013-05-04)
-----------------
- Add option to add JSON-LD in the dumpgj program.
- Compare values to six.string_types in Collection constructor.
- Add encoding to Collection.meta.
- Document dumpgj in README.

0.13 (2013-04-30)
-----------------
- Python 2/3 compatibility in a single package. Pythons 2.6, 2.7, 3.3 now supported.

0.12.1 (2013-04-16)
-------------------
- Fix messed up linking of README in sdist (#39).

0.12 (2013-04-15)
-----------------
- Fix broken installation of extension modules (#35).
- Log CPL errors at their matching Python log levels.
- Use upper case for encoding names within OGR, lower case in Python.

0.11 (2013-04-14)
-----------------
- Cythonize .pyx files (#34).
- Work with or around OGR's internal recoding of record data (#35).
- Fix bug in serialization of int/float PROJ.4 params.

0.10 (2013-03-23)
-----------------
- Add function to get the width of str type properties.
- Handle validation and schema representation of 3D geometry types (#29).
- Return {'geometry': None} in the case of a NULL geometry (#31).

0.9.1 (2013-03-07)
------------------
- Silence the logger in ogrext.so (can be overridden).
- Allow user specification of record field encoding (like 'Windows-1252' for
Natural Earth shapefiles) to help when OGR can't detect it.

0.9 (2013-03-06)
----------------
- Accessing file metadata (crs, schema, bounds) on never inspected closed files
returns None without exceptions.
- Add a dict of supported_drivers and their supported modes.
- Raise ValueError for unsupported drivers and modes.
- Remove asserts from ogrext.pyx.
- Add validate_record method to collections.
- Add helpful coordinate system functions to fiona.crs.
- Promote use of fiona.open over fiona.collection.
- Handle Shapefile's mix of LineString/Polygon and multis (#18).
- Allow users to specify width of shapefile text fields (#20).

0.8 (2012-02-21)
----------------
- Replaced .opened attribute with .closed (product of collection() is always
opened). Also a __del__() which will close a Collection, but still not to be
depended upon.
- Added writerecords method.
- Added a record buffer and better counting of records in a collection.
- Manage one iterator per collection/session.
- Added a read-only bounds property.

0.7 (2012-01-29)
----------------
- Initial timezone-naive support for date, time, and datetime fields. Don't use
these field types if you can avoid them. RFC 3339 datetimes in a string field
are much better.

0.6.2 (2012-01-10)
------------------
- Diagnose and set the driver property of collection in read mode.
- Fail if collection paths are not to files. Multi-collection workspaces are
a (maybe) TODO.

0.6.1 (2012-01-06)
------------------
- Handle the case of undefined crs for disk collections.

0.6 (2012-01-05)
----------------
- Support for collection coordinate reference systems based on Proj4.
- Redirect OGR warnings and errors to the Fiona log.
- Assert that pointers returned from the ograpi functions are not NULL before
using.

0.5 (2011-12-19)
----------------
- Support for reading and writing collections of any geometry type.
- Feature and Geometry classes replaced by mappings (dicts).
- Removal of Workspace class.

0.2 (2011-09-16)
----------------
- Rename WorldMill to Fiona.

0.1.1 (2008-12-04)
------------------
- Support for features with no geometry.


Credits
=======

Fiona is written by:

* Sean Gillies (https://github.com/sgillies)

With contributions by:

* Stefano Costa (https://github.com/steko)
* Ludovic Delauné (https://github.com/ldgeo)
* Frédéric Junod (https://github.com/fredj)
* lordi (https://github.com/lordi)
* Ariel Núñez (https://github.com/ingenieroariel)
* Oliver Tonnhofer (https://github.com/olt)
* Michael Weisman (https://github.com/mweisman)
* Andy Wilson (https://github.com/wilsaj)

Fiona would not be possible without the great work of Frank Warmerdam and other
GDAL/OGR developers.

Some portions of this work were supported by a grant (for Pleiades_) from the
U.S. National Endowment for the Humanities (http://www.neh.gov).

.. _Pleiades: http://pleiades.stoa.org