longitude inline labels don't work under geostationary projection

[IAP-FuYaNan]

Longitude inline labels don't work under the geostationary projection. If I set both latinline and loninline to True, then loninline does not work. If I set latinline to False, then loninline works fine. The script is shown below.

import numpy as np
import ultraplot as uplt
projgeo = uplt.Proj(
    'geos',
    central_longitude = 105,
    satellite_height = 35785831,
    )
fig, ax = uplt.subplots(
    proj = projgeo,
    refwidth = 5,
    figurefacecolor = 'w',
    )
ax.format(
    lonlines = np.arange(15, 200, 30),
    latlines = np.arange(-60, 61, 20),
    latlabels = True,
    latinline = True,
    lonlabels = True,
    loninline = True,
    coast = True,
    reso = 'lo',
    )
fig.save(r'/data1/fuyanan/MCS/test.png', dpi=200)

[IAP-FuYaNan]

I also want to take this opportunity to thank Casper for his goodwill and contribution to UltraPlot. He is truly a lifesaver, especially considering that development on ProPlot has been halted for more than two years.

[cvanelteren]

Hi there, thanks for the kind words 😄. Happy to help where I can.

I have the suspicion that the code is hiding your ticks for longitude since they are spaced far apart in this projection.

For example when I run this:

import ultraplot as uplt, numpy as np, pandas as pd

projgeo = uplt.Proj(
    "geos",
    central_longitude=105,
    satellite_height=35785831,
)
fig, ax = uplt.subplots(
    proj=projgeo,
    refwidth=5,
    figurefacecolor="w",
)
ax.format(
    labels=True,
    lonlines=2,
    coast=True,
    reso="lo",
)

I get :

Same for when lonline is set to True:

Which shows that they are working every 2 degrees but will not show all.
In the code I think it checks if it can place the label and will hide them if there are too many or it "doesn't look nice" -- Luke designed this over years and some of the choices are not obvious from the code alone.

So in short, I think it is not showing as the labels are hidden when it doesn't fit nicely. You can force the behavior by playing with the tick spacing.