[ncl-talk] Plot precipitation data without lat/lon coordinates

[Mary Haley]

Hi Andrew,

Take a look at the first example on this page:

http://www.ncl.ucar.edu/Applications/native.shtml

As a first cut, I would download the native_1.ncl script, and add these
lines to read some data:

 f = addfile("nws_precip_ak_20160221.nc","r")
 lat_corners = f->lat
 lon_corners = f->lon
 true_lat    = f->true_lat
 true_lon    = f->true_lon

and then change the following resource values as follows:

; The following resources are Required to plot this projection correctly

 res at mpProjection                = "Stereographic"     ; projection

 res at mpLimitMode                 = "Corners"           ; method to zoom
 res at mpLeftCornerLatF            = lat(0)
 res at mpLeftCornerLonF            = lon(0)
 res at mpRightCornerLatF           = lat(2)
 res at mpRightCornerLonF           = lon(2)

 res at mpRelativeCenterLon         = True           ; set a center lon
 res at mpCenterLonF                = true_lon       ; center lon
 res at mpRelativeCenterLat         = True       ; set a center lat
 res at mpCenterLatF                = true_lat       ; center lat
 res at tfDoNDCOverlay              = True

The one thing I'm not sure about is whether the fact that your file says
"polar stereographic" is going to make a difference. You could also set
this to get a polar plot:

 res at mpEllipticalBoundary        = True

--Mary



On Fri, May 20, 2016 at 10:43 AM, Andrew Kren - NOAA Affiliate <
andrew.kren at noaa.gov> wrote:

> Dear ncl-talk,
>
> I am trying to plot precipitation data of radar and station data from the
> NWS. It is in netcdf form. When I read in the data, the array of
> precipitation is two dimensional as expected in (lat,lon). However, there
> are no lat/lon coordinate arrays in the netcdf file. It only gives me the 4
> corners of the lon / lat grid. I am sending the filedump of the netcdf file
> so you can see the format.
>
> Is there a way in ncl to plot the data on a map without the given
> coordinate arrays?
>
> Thanks,
>
> --
> Andrew Kren, PhD
> Research Scientist I, Global Observing Systems Analysis (GOSA) Group
> NOAA ESRL Global Systems Division (Rm 3C515)
> 325 Broadway, Boulder, CO 80305
> (303) 497-5418
>
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