happysundar/pyspatialite_install_instructions.md

## pyspatialite_install_instructions.md

      
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    Install prerequisite package dependencies

From http://elgis.argeo.org/repos/6/, find the latest repo rpm, and install it as root:
`sudo rpm -Uvh http://elgis.argeo.org/repos/6/elgis-release-6-6_0.noarch.rpm`

Install Dependency Packages:


yum install python-devel (needed by Shapely to compile C extensions)
yum install bzip2 bzip2-devel (needed by Scrapy : remove this when this is no longer a dependency)
yum install gdal gdal-devel
yum install geos geos-devel
yum install proj proj-devel
yum install libxml2 libxml2-devel (needed to make xpath searching efficient)
yum install libxslt libxslt-devel
yum install sqlite sqlite-devel
yum install expat expat-devel (this is needed by spatialite-tools)

Installing pythonz and virtualenv-burrito

TODO: Add instructions for doing this
Installing libspatialite, spatialite-tools and pysqlite

Why do this


The default version of sqlite3 that is installed is not the current version (3.8.1 as of writing this), but an older version - 3.6.20 in my system. However, the current version of spatialite-tools will not compile with the older version. Hence, we have to compile/install this version. I did this from source (since my repos didn’t have the latest version).
The default ‘make install’ installs all libraries/binaries on /usr/local/lib. This is usually not where the rpm packages install the libraries (in my system, this is /usr/lib64). When building, we have to make sure that the build system looks at this directory - something we will acheive using the export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig trick.

Installing Latest Version Of Sqlite (3.8.1)

First, let’s get the latest version of sqlite3 compiled and installed (to /usr/local/lib — so this shouldn’t mess with the yum installed version). For this, head over to http://www.sqlite.org/download.html and download the latest sqlite3-autoconf tarball. For me, that was http://www.sqlite.org/2013/sqlite-autoconf-3080100.tar.gz as of this time of writing.

Download to a directory using  wget http://www.sqlite.org/2013/sqlite-autoconf-3080100.tar.gz or something similar.
Extract and cd to that directory
Do ./configure
Do sudo make install if you are not running as root (ignore ‘sudo’ if you are running as root).

Installing libspatialite


Download the latest version from  http://www.gaia-gis.it/gaia-sins/ using ‘wget http://www.gaia-gis.it/gaia-sins/libspatialite-4.1.1.zip’
Extract and cd to that directory
Do : export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
Do : ./configure  —enable-freexl=no
Do : sudo make install

Installing ReadOSM


Download the latest version from https://www.gaia-gis.it/fossil/readosm/index; For me, this was http://www.gaia-gis.it/gaia-sins/readosm-1.0.0b.tar.gz
Extract and cd to that directory
Do : export PKG_CONFIG_PATH=/usr/local/lib/pkgconfig
Do : ./configure
Do : sudo make install

Installing spatialite-tools


Download the latest version from https://www.gaia-gis.it/fossil/spatialite-tools/index. For me, this was http://www.gaia-gis.it/gaia-sins/spatialite-tools-4.1.1.tar.gz
Extract and cd to that directory
Do : ./configure  —enable-freexl=no
Do : sudo make install

Installing Pysqlite with enable_load_extension method available

Why do this

The default sqlite3 module or the external pysqlite modules don't come with the enable_load_extension method enabled (since some platforms have SQLite libraries which are compiled without this feature).
So, we have to compile the pysqlite3 extension with this feature enabled (since its easier to do this than to compile python)
Installing pysqlite

	
This is the simple part. Do:
`pip install pysqlite --no-install`

Change into the package source directory:
`cd <virtual_env_dir>/build/pysqlite`

Assuming that you have done the previous dependency install steps, you should have the sqlite 3.8.1 version installed in /usr/local/lib. Prepend that to $LD_LIBRARY_PATH:
`export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/lib`		

Edit setup.cfg and comment out the line containing this define:
`#define SQLITE_OMIT_LOAD_EXTENSION`

Now, do:
`pip install --no-download -I pysqlite`

This will compile sqlite3, and install the pysqlite package containing the latest version of sqlite3 (3.8.1 as of this writing)
Verify that this is indeed the case by doing this from the python prompt:
	from pysqlite2 import dbapi2 as sqlite3	
	sqlite3.sqlite_version_info

This should show:
`(3, 8, 1)`

Not only this, now you can load the spatialite library by doing this:
	from pysqlite2 import dbapi2 as sqlite3

	con = sqlite3.connect(":memory:") #obviously, use your actual database filename here

	con.enable_load_extension(True)				
	 
	con.execute('SELECT load_extension("/usr/local/lib/libspatialite.so")')