Fix typos in cylindrical projection examples

[yvonnefroehlich]

Description of proposed changes

This PR aims to fix a few typos in the cylindrical projection examples.

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I am not totally sure about the second paragraph of the explanation of the UTM projection, see
https://www.pygmt.org/dev/projections/cyl/cyl_universal_transverse_mercator.html?highlight=10%20away

Maybe it is ... less than 10° away ... in the last line (the unit, probably [the] degree [sign], is missing)?

However, there is also no unit in the equivalent GMT documentation, see
https://docs.generic-mapping-tools.org/dev/cookbook/map-projections.html?highlight=10%20away#universal-transverse-mercator-utm-projection-ju-ju.

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Reminders

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• Add new public functions/methods/classes to doc/api/index.rst.
• Write detailed docstrings for all functions/methods.
• If wrapping a new module, open a 'Wrap new GMT module' issue and submit reasonably-sized PRs.
• If adding new functionality, add an example to docstrings or tutorials.

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[seisman]

Requesting a review from the original author @willschlitzer (in PR #727).

[willschlitzer]

Looks good to me!

[seisman]

Maybe it is ... less than 10° away ... in the last line (the unit, probably [the] degree [sign], is missing)?

However, there is also no unit in the equivalent GMT documentation, see docs.generic-mapping-tools.org/dev/cookbook/map-projections.html?highlight=10%20away#universal-transverse-mercator-utm-projection-ju-ju.

I think your understanding is correct. If you like, please also submit a fix to the upstream GMT repository.

[seisman]

@yvonnefroehlich I've sent you an invitation to join in the GenericMappingTools/pygmt-contributors. After joining in this team, you will have write permission to the pygmt repository, so you can create branches in the pygmt repository instead of in your own fork.

[seisman]

I'm looking at the upstream GMT documentation and this example. I think this example can be further improved in the following ways:

1. The GMT documentation shows this figure, which I believe is very important to know the zone number in the projection setting. So I think we should also include this figure in this example:
   

2. Two sentences in the GMT documentation are missing in this example:

   although a standard, you can change this with PROJ_SCALE_FACTOR
   For larger regions we use the conformal latitude in the general spherical formulae instead.

3. This makes the UTM projection a secant projection and not a tangent projection like the transverse Mercator above.

   "the transverse Mercator above" doesn't make sense in this example. It should be linked to this link https://www.pygmt.org/dev/projections/cyl/cyl_transverse_mercator.html instead.

[yvonnefroehlich]

@yvonnefroehlich I've sent you an invitation to join in the GenericMappingTools/pygmt-contributors.

Thanks for inviting me to the GenericMappingTools organization! 😊 Very happy to joint the pygmt-contributors team! 😊

After joining in this team, you will have write permission to the pygmt repository, so you can create branches in the pygmt repository instead of in your own fork.

This means I finish the already opened PRs via my fork, and for all new PRs I create a branch directly in the PyGMT repro and open a PR from there, correct?

[yvonnefroehlich]

I'm looking at the upstream GMT documentation and this example. I think this example can be further improved in the following ways:

1. The GMT documentation shows this figure, which I believe is very important to know the zone number in the projection setting. So I think we should also include this figure in this example:

2. Two sentences in the GMT documentation are missing in this example:

   although a standard, you can change this with PROJ_SCALE_FACTOR
   For larger regions we use the conformal latitude in the general spherical formulae instead.

3. This makes the UTM projection a secant projection and not a tangent projection like the transverse Mercator above.

   "the transverse Mercator above" doesn't make sense in this example. It should be linked to this link https://www.pygmt.org/dev/projections/cyl/cyl_transverse_mercator.html instead.

I agree with you on all three points. My impression is that the PyGMT documentation for the projections is partly a bit shorten compared to the upstream GMT documentation. Should I open a new PR to improve the PyGMT documentation for the UTM projection regading these three points, or do you prefer that this is also handled in this PR?

[willschlitzer]

I'm looking at the upstream GMT documentation and this example. I think this example can be further improved in the following ways:

1. The GMT documentation shows this figure, which I believe is very important to know the zone number in the projection setting. So I think we should also include this figure in this example:

2. Two sentences in the GMT documentation are missing in this example:

   although a standard, you can change this with PROJ_SCALE_FACTOR
   For larger regions we use the conformal latitude in the general spherical formulae instead.

3. This makes the UTM projection a secant projection and not a tangent projection like the transverse Mercator above.

   "the transverse Mercator above" doesn't make sense in this example. It should be linked to this link https://www.pygmt.org/dev/projections/cyl/cyl_transverse_mercator.html instead.

I agree with you on all three points. My impression is that the PyGMT documentation for the projections is partly a bit shorten compared to the upstream GMT documentation. Should I open a new PR to improve the PyGMT documentation for the UTM projection regading these three points, or do you prefer that this is also handled in this PR?

My vote it to leave this PR with the current changes and open up a separate one for the UTM documentation.

[seisman]

This means I finish the already opened PRs via my fork, and for all new PRs I create a branch directly in the PyGMT repro and open a PR from there, correct?

Yes.

I agree with you on all three points. My impression is that the PyGMT documentation for the projections is partly a bit shorten compared to the upstream GMT documentation. Should I open a new PR to improve the PyGMT documentation for the UTM projection regading these three points, or do you prefer that this is also handled in this PR?

My vote it to leave this PR with the current changes and open up a separate one for the UTM documentation.

I'm OK with a separate PR.