QGIS

Installing

To install QGIS on Mac OS X:

First, I went to the download site on QGIS website:

http://www.qgis.org/en/site/forusers/download.html

I was pointed to the KygChaos wiki http://www.kyngchaos.com/software/python

At that wiki, I downloaded several provided dmg files:

• Numpy
• Matplotlib
• GDAL framework
• QGIS

I installed each, in that order. The python libraries that are being installed install to /Library/Python/2.x/site-packages - which is where libraries available to the SYSTEM version of Python are available. This will not interfere with existing versions of numpy or matplotlib libraries that you've installed using an Anaconda or Python.org or Homebrew (or other) version of python that you have installed.

Once all of those installers had been run, I opened QGIS in my Applications folder.

Basics

Opening Shapefiles

To open a shapefile, you can create a project. Then you can click the first icon in the left-hand menu, the dots connected by lines (Add a Vector Layer). Here, you can pick "ESRI Shapefile" from the drop-down menu, and you'll be able to open shapefiles.

Here's an imported shapefile of military installations in the United States (from the Harvard Library website):

Adding Tiles

The shapefile on its own probably isn't very interesting. You can add the OpenLayers plugin, which allows you to bring in map layers from Google Maps, OpenStreetMap, Bing Maps, etc.

If we now go to Web > OpenLayers plugin, we can pick from a list of different map layers provided by different services!

Now I see a much more interesting map of military installations: