Part I – QGIS installation
System Requirements – 220.8MB of disk space for application | 1GB of RAM
Step 1: Go to http://www.qgis.org/wiki/ Download and click on the Standalone Installer for Mac OS X
Step 2: Click on KyngChaos Qgis download page
Step 3: Download and install the GDAL Complete framework package
Step 4: Download and install the GSL framework
Step 5: Click on the link for YOUR operating system. If you do not know what OS your Mac is running click on the apple icon on the top left of your screen and go to ‘About this Mac’. Version 10.6.x is Snow Leopard, and 10.5.x is Leopard.
Step 6: Once the download has completed click on the download to open the file.
Step 7: When this window has opened drag the QGIS icon into your application folder.
Step 8: Now you can open QGIS from your application folder, click ‘open’ when asked if you are sure
you want to open the file because it was downloaded from the Internet.