Plotting/displaying legacy NEXRAD level II data

[kenpryor67]

Good evening-

I am attempting to plot a map of NEXRAD reflectivity data from Sterling, VA (KLWX) for September 24, 2001, using the following code: import matplotlib.pyplot as plt import pyart import numpy as np

open the file, create the displays and figure

filename = 'KLWX20010924_210141_file' radar = pyart.io.read_nexrad_archive(filename) display = pyart.graph.RadarDisplay(radar) fig = plt.figure(figsize=(6, 6))

plot super resolution reflectivity

ax = fig.add_subplot(111) display.plot('reflectivity', 0, title='NEXRAD Reflectivity 2101 UTC', vmin=20, vmax=60, colorbar_label='', ax=ax) display.plot_range_ring(radar.range['data'][-1]/1000., ax=ax) display.set_limits(xlim=(-100, 100), ylim=(-100, 100), ax=ax) plt.savefig("Z_2101.png",dpi=250,bbox_inches='tight') plt.show()

max_lat = 40.5 min_lat = 37.5 min_lon = -78.5 max_lon = -75.5

lal = np.arange(min_lat, max_lat, .5) lol = np.arange(min_lon, max_lon, .5)

display = pyart.graph.RadarMapDisplay(radar) fig = plt.figure(figsize = [10,8]) display.plot_ppi_map('reflectivity', resolution = 'h', vmin = -8, vmax = 64, mask_outside = False, cmap = pyart.graph.cm.NWSRef, projection='merc', min_lat = min_lat, min_lon = min_lon, max_lat = max_lat, max_lon = max_lon, lat_lines = lal, lon_lines = lol)

Indicate the radar location with a point

display.plot_point(-77.299990, 39.399529, symbol='bs') display.plot_point(-76.5280, 39.2190, symbol='bs') plt.savefig("Ze_lwx_2101.png",dpi=250,bbox_inches='tight')

plt.show()

The basic reflectivity plot appears as expected, however, the PPI map is generated, but no data is plotted. Could this be a dataset format issue? Any advice or guidance would be greatly appreciated!

Thanks, Ken

[scollis]

What happens when you set the tilt to 0 in the map display?

Also what happens when you do not specify any lat/lons to plot_ppi_map? Ie make the call as simple as possible? -sent from a mobile device-

On Feb 27, 2019, at 8:38 PM, kenpryor67 [email protected] wrote:

Good evening-

I am attempting to plot a map of NEXRAD reflectivity data from Sterling, VA (KLWX) for September 24, 2001, using the following code: import matplotlib.pyplot as plt import pyart import numpy as np

open the file, create the displays and figure

filename = 'KLWX20010924_210141_file' radar = pyart.io.read_nexrad_archive(filename) display = pyart.graph.RadarDisplay(radar) fig = plt.figure(figsize=(6, 6))

plot super resolution reflectivity

ax = fig.add_subplot(111) display.plot('reflectivity', 0, title='NEXRAD Reflectivity 2101 UTC', vmin=20, vmax=60, colorbar_label='', ax=ax) display.plot_range_ring(radar.range['data'][-1]/1000., ax=ax) display.set_limits(xlim=(-100, 100), ylim=(-100, 100), ax=ax) plt.savefig("Z_2101.png",dpi=250,bbox_inches='tight') plt.show()

max_lat = 40.5 min_lat = 37.5 min_lon = -78.5 max_lon = -75.5

lal = np.arange(min_lat, max_lat, .5) lol = np.arange(min_lon, max_lon, .5)

display = pyart.graph.RadarMapDisplay(radar) fig = plt.figure(figsize = [10,8]) display.plot_ppi_map('reflectivity', resolution = 'h', vmin = -8, vmax = 64, mask_outside = False, cmap = pyart.graph.cm.NWSRef, projection='merc', min_lat = min_lat, min_lon = min_lon, max_lat = max_lat, max_lon = max_lon, lat_lines = lal, lon_lines = lol)

Indicate the radar location with a point

display.plot_point(-77.299990, 39.399529, symbol='bs') display.plot_point(-76.5280, 39.2190, symbol='bs') plt.savefig("Ze_lwx_2101.png",dpi=250,bbox_inches='tight')

plt.show()

The basic reflectivity plot appears as expected, however, the PPI map is generated, but no data is plotted. Could this be a dataset format issue? Any advice or guidance would be greatly appreciated!

Thanks, Ken

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[kenpryor67]

Scott, Thanks for the quick response! I applied your suggestions, and used the following code to display the radar map. The data is now plotted, but no map boundaries appear. I'm now using a stereographic projection. What other projection would you recommend?

display = pyart.graph.RadarMapDisplay(radar) fig = plt.figure(figsize = [10,8]) display.plot_ppi_map('reflectivity', sweep=0, resolution = 'h', vmin = -8, vmax = 64, mask_outside = False, cmap = pyart.graph.cm.NWSRef, projection='stere', min_lat = None, min_lon = None, max_lat = None, max_lon = None,

Thanks again for all your help. I'm looking forward to corresponding further on this issue.

[kenpryor67]

Also- if I use a Lambert Conformal projection ('lcc'), a run time error appears: RuntimeError: conic lat_1 = -lat_2

[scollis]

Sorry we let this one lapse... @rcjackson is this a projection issue with Cartopy? if so I think gridlines in other projections is fixed now..

[rcjackson]

I believe so. I've never had an issue when using PlateCarree projection.

[mgrover1]

Closed by #1272