SciPy2013

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This repository contains materials for the tutorial Using Geospatial Data With Python_ to be held Jun 25, 2013, at the SciPy 2013 conference.

.. _Using Geospatial Data With Python: http://kjordahl.github.io/SciPy2013

Required packages

• pyproj_ python interface to PROJ.4 library
• Basemap_ plot on map projections using matplotlib
• gdal_ python bindings for Geospatial Data Abstraction Library (and OGR)
• shapely_ pythonic library for geometric tasks
• fiona_ pythonic interface to OGR data formats

Optional packages

• Cartopy_ Advanced mapping interface for python
• Descartes_ Create matplotlib Patch objects from Shapely geometries
• geoJSON_ reference implementation of the Python geo interface
• psycopg2_ for connection to PostgreSQL/PostGIS database
• SQLAlchemy_ Object Relational Model for SQL databases

.. _pyproj: http://code.google.com/p/pyproj .. _Basemap: https://github.com/matplotlib/basemap .. _Cartopy: http://scitools.org.uk/cartopy .. _Descartes: https://pypi.python.org/pypi/descartes .. _geoJSON: https://pypi.python.org/pypi/geojson .. _gdal: https://pypi.python.org/pypi/GDAL .. _shapely: http://toblerity.github.io/shapely .. _fiona: http://toblerity.github.io/fiona .. _psycopg2: https://pypi.python.org/pypi/psycopg2 .. _SQLAlchemy: http://www.sqlalchemy.org

Installation instructions

The standard scientific python stack_ is a prerequisite for this tutorial before installing the specific packages listed above. I recommend starting with a standard scientific python distribution such as Enthought Canopy_ or anaconda. All students for SciPy tutorials will have received a free license for Canopy for a limited period of time (also free for academic use, and anyone can use the free Canopy Express). Other package managers such as Linux distribution tools or homebrew for OS X will work for a starting point as well, though I have not tested these. On Windows you may be able to use Christoph Golke's binary packages_.

Install the above packages via your standard package manager when possible. For packages not available in this way (or if you wish to use a different version than available), you may install directly with pip or easy_install. For example, to install Shapely, you may use::

pip install shapely

Finally, if all else fails, or you wish to be on the bleeding edge, you may install packages from source. For example::

git clone https://github.com/Toblerity/Shapely
cd Shapely
python setup.py install

will install the current development version of Shapely.

Serge Ray has shared his setup notes_ for OS X 10.8.4 and anaconda.

.. _Enthought Canopy: https://www.enthought.com/products/canopy .. _anaconda: https://store.continuum.io/cshop/anaconda .. _scientific python stack: http://www.scipy.org/install.html .. _academic use: https://www.enthought.com/products/canopy/academic .. _Christoph Golke's binary packages: http://www.lfd.uci.edu/~gohlke/pythonlibs .. _his setup notes: osx-anaconda.md

Known installation issues

• Importing shapely in Canopy version 1.0.1 on OS X fails_ while loading the GEOS library, and throws an exception of the form "OSError: Could not find library c or load any of its variants". This can be fixed by upgrading to Canopy 1.0.3 (available soon) or worked around by setting the following environment variable::

  export DYLD_FALLBACK_LIBRARY_PATH=$(HOME)/lib:/usr/local/lib:/lib:/usr/lib

• The GDAL 1.9.0 package in Canopy fails to find the PROJ.4 library for some operations. It should work for other use cases.

• GDAL binary libraries may not be found even when they are installed, particularly when installing fiona. The fiona install process uses the command gdal-config --cflags to find header files. This should match your GDAL install location. You may need to install GDAL on your system. A number of binaries_ are available, or you could use a package manager such as fink or apt-get, or build it from source.

• Dependency errors installing psycopg2 in Canopy and EPD. This may be overcome by downloading the psycopg2 .egg file from the Enthought PyPI mirror_ and installing it manually with the egginst command, or with pip install psycopg2. Windows users can try this binary installer for psycopg2_ which has been reported to work.

.. _fails: http://stackoverflow.com/questions/17072797/enthought-canopy-cytpes-util-find-library-cant-find-libc .. _binaries: http://trac.osgeo.org/gdal/wiki/DownloadingGdalBinaries .. _Enthought PyPI mirror: https://www.enthought.com/repo/pypi/eggs .. _this binary installer for psycopg2: http://www.stickpeople.com/projects/python/win-psycopg/