Re: Plotting Antarctica

Hi Rosemarie,

Adding a bit to Mary's response, there is an example of plotting Antarctica with the Earth..4 map outlines at http://www.ncl.ucar.edu/Applications/maponly.shtml. See maponly_19.ncl. You are definitely correct that the Earth..4 outlines are much more accurate than previous versions of the Map boundaries. And Earth..4 is the only dataset that distinguishes between the ice shelves and the actual land outlines. It is quite configurable and the mpOutlineSpecifiers, mpMaskOutlineSpecifiers and mpOutlineBoundarySets resources allow for a number of ways of achieving your objective.
 -dave

On Feb 23, 2011, at 10:10 AM, Mary Haley wrote:

> Hi Rosemarie,
>
> I'm sorry, I didn't realize the Earth..3 was giving ice shelves, because it doesn't appear to be documented this way in the Earth..3 table.
>
> However, I think you can get the outlines for Antarctic only in Earth..4. I'm extremely busy right now, so I don't have time to write out a full script to try this, but what happens if set these resources? The last one is the important one:
>
> res@gsnPolar = "SH" ; Southern hemisphere
>
> res@mpDataSetName = "Earth..4" ; Database that contains the
> res@mpDataBaseVersion = "MediumRes" ; ice shelves
> res@mpMaxLatF = -60 ; Zoom in on Antarctica
> res@mpOutlineOn = True ; Turn on map outlines
> res@mpFillOn = False ; Turn off map fill
> res@mpGridAndLimbOn = False ; Turn off grid and limb lines
> res@mpPerimOn = False ; Turn off map perimeter
> res@mpGeophysicalLineColor = "red"
>
> res@mpOutlineSpecifiers = "Land . Antarctica"
>
>
> --Mary
>
> On Feb 23, 2011, at 9:41 AM, Rosemarie Drummond wrote:
>
>> Hi Mary,
>> I am afraid that my experience does not agree with you. I am attaching 2 plots of the Antarctic peninsula.
>> The contoured field is a rather coarsely-defined plot of current topography.
>> The outline given by Earth..3 has a lot of blue within the boundary because the outline goes along the edge of the ice-shelf. (in particular the blue area at the bottom of the plot is the Ronne iceshelf)
>> The outline given by Earth..4 is much more complex and is showing the edge of the Ronne icesheet and the edge of the land beneath the iceshelf.
>>
>> The documentation you referred me to says that the ice shelves "can be made to appear or not as desired". I assume that this might perhaps be done with mpOutlineSpecifiers, so I will look into that.
>> Rosemarie
>> PS In case anyone else plots Antarctica: Using LowRes gives inconsistent results showing the outer edge of the Ronne iceshelf and the land edge under the Ross iceshelf
>>
>> On 23/02/2011 10:44 AM, Mary Haley wrote:
>>> Rosemarie,
>>>
>>> I believe the Earth..3 database should be giving you the edge of the land, and not the ice shelves.
>>>
>>> If you go to the page that lists all the areas for Earth..3, you won't see any mention of ice shelves:
>>>
>>> http://www.ncl.ucar.edu/Document/HLUs/Classes/MapPlotData4_1_earth_3.shtml
>>>
>>> On the Earth..4 page, however, you do:
>>>
>>> http://www.ncl.ucar.edu/Document/HLUs/Classes/MapPlotData4_1_earth_4.shtml
>>>
>>> --Mary
>>>
>>>
>>> On Feb 22, 2011, at 12:44 PM, Rosemarie Drummond wrote:
>>>
>>>> If I plot a map of Antarctica and specify mpDataBaseVersion = "Ncarg4_1"
>>>> then if I set mpDataSetName = "Earth..3", it will plot the edge of the
>>>> ice-shelves
>>>> but if I set mpdataSetName = "Earth..4", it will plot both the edge of
>>>> the land below the ice-shelves and the edge of the ice-shelves.
>>>>
>>>> I am just wondering if there is a combination that I have missed, that
>>>> would just plot the edge of the land?
>>>>
>>>> Thanks
>>>> Rosemarie
>>>> PS I am using gsn_csm_contour_map_polar but I don't suppose that makes
>>>> any difference in this.
>>>>
>>>> --
>>>> Dr Rosemarie Drummond
>>>> rmarie@atmosp.physics.utoronto.ca
>>>>
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>>
>>
>> --
>> Dr Rosemarie Drummond
>> rmarie@atmosp.physics.utoronto.ca
>>
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Received on Wed Feb 23 11:30:56 2011