[ncl-talk] NCL plot shows a shift in the coastline

[Dave Allured - NOAA Affiliate]

Please see the NCL shapefiles example web page.  There are several examples
of drawing shape files on top of an existing plot.

In particular, shapefile_3 is a simple example of adding polylines on top
of an existing plot.  It uses the function gsn_add_shapefile_polylines.
The base plot is drawn first, then polylines are added with
gsn_add_shapefile_polylines.  Then call "draw" and "frame" as shown, to
output the completed plot.

You may need to experiment with draw order resources to get both NCL coast
lines and shapefile outlines to plot on top of your data filled areas.


On Mon, Jan 27, 2020 at 2:48 PM Kunal Dayal <kday202 at aucklanduni.ac.nz>
wrote:

> Hi Dave,
>
> How can I do what you are recommending?
>
> Appreciate guidance.
>
> Regards
> Kunal
>
> On Fri, 24 Jan 2020 at 13:36, Dave Allured - NOAA Affiliate <
> dave.allured at noaa.gov> wrote:
>
>> It might also be helpful to get an accurate outline shape file of Fiji
>> islands, and add that on top of your current plot.  This would help
>> diagnose alignment problems in your data coordinates, NCL coast line
>> database, or both.
>>
>>
>> On Thu, Jan 23, 2020 at 3:50 PM Rick Brownrigg via ncl-talk <
>> ncl-talk at ucar.edu> wrote:
>>
>>> Hi,
>>>
>>> It's hard to say exactly without more information (like your script,
>>> data source, etc). However I don't think it's a download/dependency issue.
>>> NCL has its own set of map databases, and it appears that the lowest
>>> resolution one is being used in your plot. For a plot at such large scale,
>>> you might want to consider using the RANGS database:
>>>
>>>     http://ncl.ucar.edu/Applications/mapoutlines.shtml
>>>
>>> Look at item #3 "HighRes", for pointers and on where to get the RANGS
>>> database (its not distributed with NCL, but is readily available),
>>>
>>> Hope that helps...
>>> Rick
>>>
>>>
>>> On Thu, Jan 23, 2020 at 3:39 PM Kunal Dayal via ncl-talk <
>>> ncl-talk at ucar.edu> wrote:
>>>
>>>> Hi,
>>>>
>>>> I am using NCL-6.6.2 on an HPC cluster for mapping WRF output files.
>>>>
>>>> I am having a slight problem with the plots as the coastline is shifted
>>>> to the west from the original location.
>>>>
>>>> What can be the possible reasons? Is it because of some differences in
>>>> the dependencies used while installing NCL or something else? And how can I
>>>> fix this problem?
>>>>
>>>> I am attaching a map showing the shift in the coastline.
>>>>
>>>> Appreciate your assistance and advice.
>>>>
>>>> Regards
>>>> Kunal
>>>>
>>>
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