Environment Variables

PyGMT’s behavior can be controlled through various environment variables. These variables can be set either in your shell environment or within your Python script using the os.environ dictionary.

Here we list the environment variables used by PyGMT which are categorized into three groups:

  1. System environment variables

  2. GMT/PyGMT environment variables

  3. Module-specific environment variables

System Environment Variables

TZ

Specify the time zone for the current calendar time. It can be set to a string that defines the timezone, such as "UTC", "America/New_York", or "Europe/London". Refer to Specifying the Time Zone with TZ for the valid format. If not set, the system’s default timezone is used.

GMT/PyGMT Environment Variables

GMT_LIBRARY_PATH

Specify the directory where the GMT shared library is located. This is useful when GMT is installed in a non-standard location or when you want to use a specific version of GMT. If not set, PyGMT will attempt to find the GMT library in standard system locations.

PYGMT_USE_EXTERNAL_DISPLAY

Whether to use external viewers for displaying images. If set to "false", PyGMT will not attempt to open images in external viewers. This can be useful when running tests or building the documentation to avoid popping up windows.

Module-Specific Environment Variables

X2SYS_HOME

Specify the directory where x2sys databases and related settings will be stored. This environment variable is used by x2sys-related functions (e.g., pygmt.x2sys_init) to manage and access x2sys data. If not set, these functions will use a default directory or prompt for a location.