PostGIS Installation
PostGIS is a spatial database extender for PostgreSQL object-relational database. It adds support for geographic objects allowing location queries to be run in SQL.
Installation Commands
Going off of http://trac.osgeo.org/postgis/wiki/UsersWikiPostGIS23UbuntuPGSQL96Apt
$ lsb_release --codename Codename: trusty $ sudo sh -c 'echo "deb http://apt.postgresql.org/pub/repos/apt trusty-pgdg main" >> /etc/apt/sources.list' $ wget --quiet -O - http://apt.postgresql.org/pub/repos/apt/ACCC4CF8.asc | sudo apt-key add - $ sudo apt-get update $ psql -V psql (PostgreSQL) 9.5.4 $ sudo apt install postgresql-9.5-postgis-2.3 $ sudo apt-get install --no-install-recommends postgis
Note the last line. Without the --no-install-recommends
line postgres assumes you're using the default configuration (in this case, postgis for postgresql 9.6). Since we're using a different flavor of postgis, we do not want this.
The postgis
apt package is not the extension to postgres. It is a collection of command line utilities for importing and exporting data to a postgis db.
Creating a Postgis DB
Initial Setup
$ createdb --username researcher tigertest $ psql --username researcher --dbname tigertest > create extension postgis; > select postgis_full_version(); -- sanity test and make sure installed and enabled > \q
Bulk Download TIGER Shapefiles
For example, say we want all of the state-level place data. The first step is to find a programmatic URL that we can use. You can inspect the HTML on the HTML interface to place data to get the correct mapping of states/territories to two digit integer. Note that they are not necessarily sequential and there is not strictly fifty.
$ for i in $(seq -f "%02g" 1 80); do wget "https://www2.census.gov/geo/tiger/TIGER2016/PLACE/tl_2016_${i}_place.zip"; sleep 3 # not necessary but a good guy scraper move done; $ for f in *.zip; do unzip "$f"; done $ for f in *.shp; do shp2pgsql -I "$f" | psql -U researcher -d tigertest; done $ psql --username researcher --dbname tigertest > select count(*) from tl_2016_01_place; -- 585
Also say we want to separate New York City, New York into a more granular by-borough set of polygons. Using City University of New York data, we will import this shapefile.
$ curl --insecure https://archive.nyu.edu/retrieve/74704/nyu_2451_34505.zip > /tmp/boroughs.zip $ cd /tmp $ unzip boroughs.zip $ shp2pgsql -I nyu_2451_34505/nyu_2451_34505.shp | psql -U researcher -d tigertest $ psql --username researcher --dbname tigertest > select count(*) from nyu_2451_34505; > \q
Translating Table names to corresponding States
tl_2016_01_place --> Alabama tl_2016_02_place --> Alaska (... 03 ... ) --> N/A tl_2016_04_place --> Arizona tl_2016_05_place --> Arkansas tl_2016_06_place --> California (... 07 ... ) --> N/A tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama tl_2016_01_place --> Alabama