Reading a file file gridded from Radx

[rrniii]

I have used radx to grid some cfradial files. I would now like to read them in with grid_io.

I had a go at adding a few things into translate between the variable names of the two file types and was successful at a gradx gridded file in but I am still unable to plot the data using display.plot_grid.

I believe the issues is in the setting up of the origin_* variables and projection dict as the code crases when I try display.get_basemap().

Attached #is the file I am trying to open and the ipython notebook I am using to explore this issue.
notebookandtestfile.zip

[nguy]

@rrniii I'm not super familiar with the Grid side, but from the error message and looking at the reference manual I think you need to create a basemap instance and add it to the GridMapDisplay after you create it. The following added to your example code creates a basemap, but I still don't get any output on the plot.

corners = [dset.variables['lon0'][:].min(), dset.variables['lon0'][:].max(), 
                 dset.variables['lat0'][:].min(), dset.variables['lat0'][:].max()]

lon0 = corners[0] + np.abs(corners[1]-corners[0])/2
lat0 = corners[2] + np.abs(corners[3]-corners[2])/2

fig, ax = plt.subplots(1, 1, figsize=(15, 8))
bm = display.plot_basemap(lat_lines=np.linspace(corners[0], corners[1], 5), 
                          lon_lines=np.linspace(corners[2], corners[3], 5), resolution='l',
                          auto_range=False, min_lon=corners[0], max_lon=corners[1], 
                          min_lat=corners[2], max_lat=corners[3], 
                          projection='tmerc', lat_0=lat0, lon_0=lon0, ax=ax)
p = display.plot_grid('dBZ', level=20, ax=ax)

[rrniii]

Thanks @nguy. Your suggestion bumped me into the correct direction. I now have a solution that works. It all came to making my own projParams dictionary from the info in the radx file and getting the correct units. To plot, I still have to set up a basemap (i.e., it does not plot in one step like a grid made with pyart's internal functions. I think this possibly is due to arrays versus lists versus tuples or and possibly some missing info in the proj Params).

I attach an example file from before, a python notebook where I work through all the issues and an altered version of grid_io that was the additional function defined that reads in this file and allows for expansion to further projections.

readingradxgriddeddatawithpyart_10Aug2016.zip

[nguy]

Glad it's working @rrniii !

@jjhelmus Is it feasible to provide either a conversion utility for RadX to Py-ART? Or does this exist, the documentation for the radx portion isn't very clear. A related thing I am encountering is to figure out a way to pipe Sigmet files through Radx to apply geolocation corrections for mobile platforms. I can do this in a separate step, and this may be the way to go, but wondered about making it more seamless.

[nguy]

@rrniii I just looked at the examples you provided. How general is the radx_grid routine you used? You might consider submitting this as a pull request so that it becomes part of the base code. Good candidate for the pyart.aux_io methods?

[jjhelmus]

@rrniii Really nice work! It looks like Py-ART should be capable of reading in grid files created with RadX. I tracked down an issue in Py-ART's coordinate transform code, #568, which I think was causing the issue with plotting these grids without providing explicit basemap parameters. With that fix and a few modification to the code you provided, plotting RadX grids using Py-ART can now be done with:

read_radx_grid('./RAINS_uncal_BNG_5km20160607_222951.nc')
display = pyart.graph.GridMapDisplay(grid)
display.plot_basemap()
display.plot_grid('CCOR', level=10)
plt.show()

I have modified your code a bit and would be happy to add this functionality to Py-ART if you are interested. If you would rather submit the change yourself I'd be happy to help you in this process also.

[jjhelmus]

Is it feasible to provide either a conversion utility for RadX to Py-ART? Or does this exist, the documentation for the radx portion isn't very clear. A related thing I am encountering is to figure out a way to pipe Sigmet files through Radx to apply geolocation corrections for mobile platforms. I can do this in a separate step, and this may be the way to go, but wondered about making it more seamless.

This is the first for supporting Radx grid files in Py-ART. Radar files written by Radx should be CfRadial compliant and can be read with pyart.io.read_cfradial. In addition, the pyart.aux_io.read_radx function can be used to pipe Sigmet/Dorade/etc files through Radx and read the result without needed to drop to the command line. The source of that function might help you create a function to apply the geolocations corrections using Radx without using a separate step.

[nguy]

I'll look at how the input command is structured and the possibility of extending the input if needed. Thanks @jjhelmus

[jjhelmus]

@rrniii Wanted to check on this issue. I wrote up a function which can read in NetCDF grid files from RadX based on your code. If you approve I will add it to Py-ART.

[scollis]

Where are we at on this? I know Brenda Dolan from CSU was interested in this.. @rrniii Did this work? @jjhelmus Did this go in a Pull request some where?

[nguy]

A ping on this topic, it was raised again at the AMS Open software short course.

[rrniii]

Sorry for being lame. Ill get on this. Glad there is interest.

…

On Aug 28, 2017, at 9:00 AM, Nick Guy ***@***.***> wrote: A ping on this topic, it was raised again at the AMS Open software short course. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#566 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/APbprjceYBJ0Rroxe8k6Bo013pbKgItFks5scsgAgaJpZM4JgPGL>.

[nguy]

Being lame is my gig.
Thanks for looking at this again.

[scollis]

@rrniii Is this working for you? If I don't hear back I will close this issue in a few days (clean out time)

[rrniii]

Hey Scott, I thought I had this working. I am away on a filed campaign and crunched for time but I think I can get it up there when back.

…

On 22 May 2018, at 14:33, Scott ***@***.***> wrote: @rrniii <https://github.com/rrniii> Is this working for you? If I don't hear back I will close this issue in a few days (clean out time) — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#566 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/APbprrTFegc-GOR07F-y3tKBlgonzhfJks5t1BOmgaJpZM4JgPGL>.

[zssherman]

Added in #1005 closing