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[python #XNB-470459]: A question about wind barbs in the dateline of the Pacific (180 degrees) using Cartopy?
- Subject: [python #XNB-470459]: A question about wind barbs in the dateline of the Pacific (180 degrees) using Cartopy?
- Date: Thu, 20 Jul 2023 16:51:37 -0600
Greetings!
> First, I keep missing your python classes, our you have any online classes
> soon?
We haven't offered an online one in a bit, we've been working behind the scenes
on reworking how we offer that training. I'll keep a note of your interest as
we look towards our next workshop schedule.
> Second, I would like to show 100mb winds across the Pacific (see attachment).
> I can do this with contouring packages using the following code segments:
I was able to make a quiver work with some synthetic data as:
import cartopy.crs as ccrs
import cartopy.feature as cfeature
import matplotlib.pyplot as plt
import numpy as np
center_lon = 180
fig = plt.figure(figsize=[9, 9], facecolor='lightgrey')
ax = fig.add_subplot(1, 1, 1,
projection=ccrs.PlateCarree(central_longitude=center_lon))
ax.set_extent([100, 265, -25, 50], crs=ccrs.PlateCarree())
ax.add_feature(cfeature.STATES, edgecolor='white', linewidth=1.5)
ax.add_feature(cfeature.COASTLINE, edgecolor='white', linewidth=2.0)
ax.add_feature(cfeature.LAND)
lon = np.linspace(-120, 120, 10)
lat = np.linspace(-10, 40, 5)
lon2D_sub, lat2D_sub = np.meshgrid(lon, lat)
u_sub = np.full_like(lon2D_sub, 5)
v_sub = np.full_like(lon2D_sub, 5)
Q = plt.quiver(lon2D_sub, lat2D_sub, u_sub, v_sub, angles="xy",
color='black',
units='width',transform=ccrs.PlateCarree(central_longitude=center_lon))
This worked fine for me here with Cartopy 0.21.1.
I suspect that this is heavily dependent on:
1. Having the data in the right "kind" of longitude; I used the -180 -> 180
system
2. Having the data for the eastern hemisphere before the data for the western
Maybe the synthetic data I created above can shed some light on where yours
differs?
Hope this helps,
Ryan
Ticket Details
===================
Ticket ID: XNB-470459
Department: Support Python
Priority: Low
Status: Closed
===================
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