Unset GMT_DATA_SERVER and use the default value

[seisman]

Description of proposed changes

As mentioned in #1556 (comment), the GMT server issue has been fixed. Now it's OK to use the default GMT server URL.

Partially reverts #1553.

Reminders

• Run make format and make check to make sure the code follows the style guide.
• Add tests for new features or tests that would have caught the bug that you're fixing.
• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If adding new functionality, add an example to docstrings or tutorials.

Slash Commands

You can write slash commands (/command) in the first line of a comment to perform
specific operations. Supported slash commands are:

• /format: automatically format and lint the code
• /test-gmt-dev: run full tests on the latest GMT development version

[weiji14]

Do we need to uncache the @N30W120.earth_relief_15s_p.nc tile? I see that GenericMappingTools/gmt#5829 has been closed in GenericMappingTools/gmt#5834. Otherwise we might forget to uncache that tile when PyGMT bumps to GMT>=6.3.

[seisman]

Uncaching the @N30W120.earth_relief_15s_p.nc tile means that building the documentation will take more time for downloading the tile and may fail on Windows and macOS due to GitHub Action internet connection issues.

I'm OK with delaying this PR after we bump to GMT 6.3.0.

[weiji14]

Uncaching the @N30W120.earth_relief_15s_p.nc tile means that building the documentation will take more time for downloading the tile and may fail on Windows and macOS due to GitHub Action internet connection issues.

I'm OK with delaying this PR after we bump to GMT 6.3.0.

Well, I quite like using https (kinda surprised the default is http to be honest). Let's keep the GMT_DATA_SERVER setting on for a little longer 🙂

[weiji14]

Do you think we could use this branch (or open another PR) to see how many tests break in PyGMT with the new SRTM v2.3 earth_relief grids? Specifically, by setting GMT_DATA_SERVER=https://test.generic-mapping-tools.org (xref GenericMappingTools/gmtserver-admin#118) on the macOS workflow for ci_tests_dev.yaml.

[maxrjones]

Do you think we could use this branch (or open another PR) to see how many tests break in PyGMT with the new SRTM v2.3 earth_relief grids? Specifically, by setting GMT_DATA_SERVER=https://test.generic-mapping-tools.org (xref GenericMappingTools/gmtserver-admin#118) on the macOS workflow for ci_tests_dev.yaml.

The ssl certificate isn't set up, so I don't think https would work yet. I've asked about getting it updated.

[seisman]

I think it's time to unset the GMT_DATA_SERVER value, so that we know the default server setting works.