Re: [ferret_users] land_detail missing Nunavut

[mick spillane <mick.spillane@xxxxxxxx>]

Hi Derek,

   In the Ferret package I use continent, country and state border data 
come from a file geo_borders.cdf which does not appear to have borders 
for Canada/Nunavut.  There would then appear to be a couple of options:

1) the quick & dirty approach -- in the graphic you included in your 
query the Nunavut border is pretty simple (10-20 lat,lon pairs would 
seem to do it) so if you had those coords in a simple ascii file (say 
NunavutBorder.dat) with missing value codes -999 to raise the pen at the 
water crossings you could use

file/form=free/var=nunlon,nunlat NunavutBorder.dat ; set var/bad=-999 nunlon
plot/o/vs/nolab/line=2 nunlon,nunlat

to add the border to a plot you had already prepared.

2) The "do it right" approach: Clearly what is needed is a variant of 
"geo_borders.cdf" that includes the extra boundaries.  Perhaps someone 
will already have such a file to share, but if not there is a wealth of 
free GIS datasets from which it is possible to extract the lat,lon pairs 
to extend geo_borders or make a separate "canada_borders" file.  Doing a 
Google led me to 
               
http://www.weather.gov/geodata/catalog/national/html/province.htm
which looks like it would be detailed enough.  This, or another GIS 
dataset, would include a "shapefile" which could be converted to ASCII 
with a tool like "shpdump".  This you would edit to remove all but the 
lon,lat pairs (and perhaps add an index variable to denote 
subregion/province) with missing values for "pen-up" as before.  This 
ASCII file you could read into Ferret and use directly, or perhaps 
output as a netCDF file to distribute to fellow Ferret users with 
appropriate recognition to the original data source. Or with 
ncdump/edit/ncgen you could insert it in the datafile "land_detail" employs.

Hope this helps ... perhaps others with related problems if the datafile 
you need is forthcoming from another user.

Good luck,
   Mick
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Derek Tsui wrote:
> Dear Ferret Users,
>
> I am using land_detail to draw boundaries and noticed that the Nunavut 
> boundary is missing. Is there anyway to add this? Do I need to modify 
> land_detail? Any suggestions would help.
>  
> Thanks,
> Derek
>
> ------------------------------------------------------------------------