[ncl-talk] help plot

[Rick Brownrigg]

Looking at your data, they both have these 7 lines of header information:

ncols 129
nrows 156
xllcorner -70.8944
yllcorner -35.3167
xdim 0.0110168
ydim 0.00898743
NODATA_value -9999

The xdim/ydim are confusing named -- I might surmise they are distance
between successive grid points?  If so, the data span an area of only about
1.4 degrees -- is that your understanding?

The attached script *may* do what you want. It parses the header, and
construct 2D coordinate arrays from the header values. It then uses
gsn_coordinates to plot the non-missing value locations. I don't know with
any certainty whether the data are ordered sout->north or north->south; the
script assumes the former.

In general, you'll want to be familiar with the pages below. Hope that helps

Rick

https://www.ncl.ucar.edu/Applications/read_ascii.shtml
https://www.ncl.ucar.edu/Document/Graphics/overlays_on_map.shtml

<https://www.ncl.ucar.edu/Document/Graphics/overlays_on_map.shtml>

<https://www.ncl.ucar.edu/Document/Graphics/overlays_on_map.shtml>

<https://www.ncl.ucar.edu/Document/Graphics/overlays_on_map.shtml>
<https://www.ncl.ucar.edu/Document/Graphics/overlays_on_map.shtml>

On Fri, Jan 5, 2018 at 6:41 AM, Vanúcia Schumacher via ncl-talk <
ncl-talk at ucar.edu> wrote:

> I have outputs data from a model (attached) with information per pixel, so
> where is -9999 are pixels that don't have  information.
>
> The outputs are for a specific region, however the data are like a mask
> and has no lat and lon information.
>
> How can I plot this data on a map, to spatially visualize the pixels that
> contain information?
>
> I tried the gsn_add_polymarker function, but it requires lat and lon
> information.
> Some help?
>
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