Add gallery example for grdclip

[michaelgrund]

Description of proposed changes

Since noone worked on this issue during the scipy-sprint here's a gallery example adressing #1384.

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

[michaelgrund]

/format

[seisman]

The 1 arc minute global relief data is NOT cached in the CI. We should either cache the 01m data or use a lower resolution earth relief.

[michaelgrund]

I would prefer to use a high resolution as the 1 arc minute global relief, otherwise the map looks bad. Will add the 01m data to cache in a separate PR (#1398).

[weiji14]

Or can we use a different location? I like the Hawaii example, but caching the 1 arc minute data (258MB) isn't very feasible... How about another island like Iceland (or another medium-ish sized one).

[seisman]

Or can we use a different location? I like the Hawaii example, but caching the 1 arc minute data (258MB) isn't very feasible... How about another island like Iceland (or another medium-ish sized one).

Sounds a better solution.

[michaelgrund]

I changed it to the 3 arc minute grid (27 MB) for the area around Iceland. Is that fine or still to large for caching?

[weiji14]

The current cache size is 30.5MB (https://github.com/GenericMappingTools/pygmt/actions/runs/1064597430), so adding 27MB would make it 50.5MB. I'm still a bit hesitant to add it... How about adding just the tile that is downloaded. Running gmt grdcut @earth_relief_03m -R-28/-10/62/68 -Gtemp.nc gives me the tile name "N00W090.earth_relief_03m_p" in .gmt/server/earth/earth_relief/earth_relief_03m_p so maybe try just caching that?

[michaelgrund]

The current cache size is 30.5MB (https://github.com/GenericMappingTools/pygmt/actions/runs/1064597430), so adding 27MB would make it 50.5MB. I'm still a bit hesitant to add it... How about adding just the tile that is downloaded. Running gmt grdcut @earth_relief_03m -R-28/-10/62/68 -Gtemp.nc gives me the tile name "N00W090.earth_relief_03m_p" in .gmt/server/earth/earth_relief/earth_relief_03m_p so maybe try just caching that?

Does adding "N00W090.earth_relief_03m_p" allow to automatically use only this tile for plotting or is there anything else to consider @weiji14 ?

[core-man]

See another similar case:

pygmt/pygmt/helpers/testing.py

Line 163 in 6a4b871

"@N35E135.earth_relief_03s_g.nc",

So, I think we could only cache such a single tile. See some notes for this case in #985 (comment).

[michaelgrund]

See another similar case:

pygmt/pygmt/helpers/testing.py

Line 163 in 6a4b871

"@N35E135.earth_relief_03s_g.nc",

I think we could only cache such a single tile.

I already recognized this one 😉 . My question is: Is that tile automatically used by pygmt.datasets.load_earth_relief() when the corresponding region is defined?

[seisman]

Is that tile automatically used by pygmt.datasets.load_earth_relief() when the corresponding region is defined?

Yes.

[core-man]

Great~~~We have one more gallery~ 😄