[ncl-talk] Plotting climate division and counties at the same time

[Rick Brownrigg]

(please ignore the previous unintelligible post -- accidentally got away
from me)

Hi Ling,

I too did not fully understand your original post and why you were
introducing the  climdiv_polygon.nc dataset. I see the issue now.   As far
as I know, there is no other readily available source of these boundaries
that's guaranteed to line up with NCL's map database.

At first, I thought perhaps overlay plots, using Earth..2 and Earth..3 as
in your original attempt would work. But after trying this, I learned that
map-plot objects can not be overlaid on top of other plots (they can only
be the base plot in an overlay).

I hesitate to even show this second possibility, because it is a giant
hack. But it involves suppressing framing of the page, and drawing two maps
directly on top of each other. All the external annotations (labels,
titles, tick marks, labelbars, etc.) have to be the same in both plots or
the two maps won't line up on the page;  this trick might not work for your
case.

In any event, attached is a script that shows climate divisions for
Colorado along with the county boundary for Boulder county. It uses NCLs
internal database in both case.   It is drawn from the last example
(shapefile_15.ncl) on the following page, and heavily modified:

     http://ncl.ucar.edu/Applications/maponly.shtml
<http://ncl.ucar.edu/Applications/maponly.shtml>

I wish I had a better answer...
Rick



On Thu, Apr 16, 2015 at 3:15 PM, Rick Brownrigg <brownrig at ucar.edu> wrote:

>
>
> It is drawn from the last example (shapefile_15.ncl) on the following
> page, and heavily modified:
>
> http://ncl.ucar.edu/Applications/maponly.shtml
>
> and is hea
>
> On Thu, Apr 16, 2015 at 9:48 AM, Ling Huang <hlbutterflyut at gmail.com>
> wrote:
>
>> Hi Rick,
>>
>> As pointed by Alan, the climate division boundaries should align with the
>> county boundaries, IF both were from NCL's default settings.
>>
>> I guess the problem lies in the "climdiv_polygon.nc" file that I
>> downloaded from NCL's website. The latitude and longitude provided by this
>> file seem mismatched with the default NCL setting as shown below. Maybe
>> there is another file that is more consistent with NCL's default setting?
>>
>> Thanks
>>
>> Ling
>>
>> [image: Displaying image.png]
>>
>> On Thu, Apr 16, 2015 at 8:51 AM, Rick Brownrigg <brownrig at ucar.edu>
>> wrote:
>>
>>> Hi Ling,
>>>
>>> This is a tough one -- off hand it looks like a classic issue of mixing
>>> two disparate geodata sources of very different scales/resolutions, which
>>> typically incur alignment/registration issues. If that's what is going on,
>>> I don't think there's much you can really do about it. Do you know what are
>>> the relative scales of the different sources?   Is there a reason to
>>> believe the climate division boundaries would align with the county
>>> (political) boundaries? (e.g., are they semi-arbitrarily defined that way
>>> for convenience?)
>>>
>>> Rick
>>>
>>> On Wed, Apr 15, 2015 at 9:43 PM, Ling Huang <hlbutterflyut at gmail.com>
>>> wrote:
>>>
>>>> Dear NCL talk,
>>>>
>>>> I want to show boundaries of climate division and counties over the
>>>> same plot. But the boundaries of climate divisions and counties are
>>>> provided by different map dataset, which means I can only draw each at a
>>>> time. Is there a way that I can show them at the same time? For example, I
>>>> want to combine the following two plots into one plot.
>>>>
>>>> The left one shows the boundaries of climate divisions and the right
>>>> one shows county.
>>>>
>>>> [image: Inline image 1][image: Inline image 2]
>>>>
>>>> I tried to load counties boundaries while reading the "
>>>> climdiv_polygons.nc" to plot a polyline for the climate division. But
>>>> it seems the boundaries do not match, like below:
>>>>
>>>> [image: Inline image 3]
>>>>
>>>> Is there a way that I can do this?
>>>>
>>>> Thank you very much!
>>>>
>>>> Ling
>>>>
>>>> _______________________________________________
>>>> ncl-talk mailing list
>>>> List instructions, subscriber options, unsubscribe:
>>>> http://mailman.ucar.edu/mailman/listinfo/ncl-talk
>>>>
>>>>
>>>
>>
>
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