2.5. Installation in Mac OS

2.5.1. QGIS download and installation

  • Visit the website KyngChaos and download the latest QGIS disk image (including Python and GDAL). QGIS 3.16 is recommended at the moment.

    WARNING: it is recommended to install only one versions of QGIS; for a clean QGIS installation, uninstall any previous version of QGIS and remove all the related directories.

  • Follow the Readme instructions and clean up any previous path settings. Python must be installed prior to GDAL and QGIS.

Now, QGIS is installed.

_images/QGIS.jpg

2.5.2. Semi-Automatic Classification Plugin installation

  • Run QGIS;
  • From the main menu, select Plugins > Manage and Install Plugins;
_images/install.jpg _images/plugins.jpg
  • The SCP should be automatically activated; however, be sure that the Semi-Automatic Classification Plugin is checked in the menu Installed (the restart of QGIS could be necessary to complete the SCP installation);
_images/plugins_installed.jpg

2.5.3. Configuration of the plugin

Now, the Semi-Automatic Classification Plugin is installed and a dock and a toolbar should be added to QGIS. Also, a SCP menu is available in the Menu Bar of QGIS. It is possible to move the toolbar and the dock according to your needs, as in the following image.

_images/SemiAutomaticClassificationPlugin.jpg

The configuration of available RAM is recommended in order to reduce the processing time. From the SCP menu select settings_tool Settings > Processing .

_images/settings_processing.jpg

In the Settings, set the Available RAM (MB) to a value that should be half of the system RAM. For instance, if your system has 2GB of RAM, set the value to 1024MB.

_images/settings_processing_tab.png

2.5.4. Installation issues

In case of missing dependencies, you could get error messages such as the following example with matplotlib:

_images/error_message_mac.jpg

A solution is to follow these steps as described in this GIS Stackexchange post :

  • Download and install Python from https://www.python.org/downloads/mac-osx/ selecting the macOS 64-bit installer;

  • Download and install the complete GDAL installer from https://www.kyngchaos.com/software/frameworks/ ;

    TIP: In case of warnings about malicious software go to the Apple menu > System Preferences > Security & Privacy > General Tab > Allow Anyway ; Python should be in Library > Frameworks > Python.framework ; GDAL should be in Library > Application Support > GDAL

  • Open QGIS, go to Settings > Options > System > Environment and enable Use Custom Variables ;

  • Select Prepend, under variable enter PATH, under value enter the path to GDAL /Library/Frameworks/GDAL.framework/Programs:/Library/Frameworks/Python.framework/Versions/3.8/bin: ;

    TIP: In case of GDAL was installed through Macports, the path to GDAL should be /opt/local/bin/:

  • Restart QGIS.