Help with Creating Oblique Mercator

[eemcmullan]

Hello! I have been trying to create an oblique mercator with no success. Using the example from the “GMT” docs, could anyone verify I am translating this correctly? Thanks in advance!

[maxrjones]

The screenshot of the code is difficult to read. Could you please cut and paste the PyGMT code to share? You can format it as code using three back-ticks before and after the block of code. For example:

```
code
```
produces

code

[eemcmullan]

Of course; sorry about that!

fig = pygmt.Figure()
fig.coast(projection="Oc280/25.5/22/69/12c",
    region= [270, 305, 20, 25],
    frame="afg",
    land="gray",
    water="lightblue",
    )
fig.show()

The goal was to get an oblique view of the Caribbean, but am having little success.

[weiji14]

Hi @eemcmullan, could you also report the output or error you are getting? I can run your example fine, this is the figure I am getting with your code above:

Maybe try posting the output of pygmt.show_versions(), in case there is something amiss with your installation, so that we can help debug.

[eemcmullan]

I apologize, I don’t think my question was very good! I did get that output for my code. However, I am more-so wondering how this map from the GMT docs can be achieved with PyGMT, as using that region and projection doesn’t seem to work for me. Sorry again!

[maxrjones]

Good question! Here is an example for that plot:

import pygmt

fig = pygmt.Figure()
fig.coast(projection="Oc280/25.5/22/69/12c",
    region="270/20/305/25+r",
    frame="afg",
    land="gray",
    water="lightblue",
    )
fig.show()

Specifically, you need to use a string for the region parameter so that you can append +r to denote that the coordinates are for the bottom-left and top-right corners.

We can improve the API docs about the region parameter; right now the best resource for an explanation about this is the ‘setting the region’ tutorial: https://www.pygmt.org/dev/tutorials/regions.html.

[Joaquim]

This is one of the cases where the wrappers could detect the situation and do the appropriate -R…+r call under the hood.
(took a mental note to implement this in Julia)

[eemcmullan]

I gotcha, thanks so much for the help!

[willschlitzer]

Currently working on a PR with gallery examples for the oblique Mercator projections; I’m only able to pass regions using a string with +r and have the figure turn out as expected, and haven’t had any luck using a Python list. Is using a list possible or should the guidance for oblique Mercator figures be to use a string?