[ncl-talk] high resolution png image

[Micah Sklut]

Okay, thanks for explaining how the raster fill works Kyle. That does help
me understand this limitation. With respect to processing time between
rasterFill and areaFill. It took about 1-2 minutes for rasterFill, compared
to a ball park of 4 hours for areaFill. Quite a difference!

On Thu, Oct 30, 2014 at 1:26 PM, Kyle Griffin <ksgriffin2 at wisc.edu> wrote:

> That's part of the definition of Raster fill - it will always create the
> same number of boxes regardless of resolution of the data underneath,
> typically based on an average of the data points within that set of grid
> points. Although I'm not knowledgeable about the behind-the-scenes
> computations, I know it's common for NCL to mark the whole average as
> missing if any subset of that average is missing. I'm not sure if there's a
> way to override this - a developer might need to chime in here - but that
> would be your only hope if you want to keep your image production time
> down, as the other fill modes will almost certainly be more intensive. You
> can scan examples of Raster Fill code here (see link) and in the contour
> resources page as well.
>
> https://www.ncl.ucar.edu/Applications/raster.shtml
>
> If you did AreaFill or CellFill, I don't think you see much difference in
> the time to produce a vector file output versus a raster image output. But
> yes, what you are seeing is a limitation of using the RasterFill setting.
>
>
> Kyle
>
> ----------------------------------------
> Kyle S. Griffin
> Department of Atmospheric and Oceanic Sciences
> University of Wisconsin - Madison
> Room 1421
> 1225 W Dayton St, Madison, WI 53706
> Email: ksgriffin2 at wisc.edu
>
> On Thu, Oct 30, 2014 at 11:55 AM, Micah Sklut <micahs2005 at gmail.com>
> wrote:
>
>> No, I"m not masking data. Yes, I am using RasterFill, and the resulting
>> image for the Mid Atlantic is great. But, when I expand to global, I lose
>> the high detail, no matter how much I increase the png resolution. So, just
>> wondering why I am losing detail with the global image, and if there is a
>> way around it.
>>
>> On Thu, Oct 30, 2014 at 12:52 PM, Kyle Griffin <ksgriffin2 at wisc.edu>
>> wrote:
>>
>>> Hi Micah,
>>>
>>> This seems to me the type of result you would expect when using
>>> RasterFill as a cnFillMode - the default should be cnAreaFill, which
>>> increases plot time significantly, but might that be an issue?
>>> Otherwise, I assume you're doing nothing else to mask the data, correct?
>>> Sometimes masking data with a land mask can create similar blockiness,
>>> although I am unaware (via inexperience) as to whether there is a
>>> resolution dependence based on the plot size or native data resolution.
>>>
>>>
>>> Kyle
>>>
>>> ----------------------------------------
>>> Kyle S. Griffin
>>> Department of Atmospheric and Oceanic Sciences
>>> University of Wisconsin - Madison
>>> Room 1421
>>> 1225 W Dayton St, Madison, WI 53706
>>> Email: ksgriffin2 at wisc.edu
>>>
>>> On Thu, Oct 30, 2014 at 11:37 AM, Micah Sklut <micahs2005 at gmail.com>
>>> wrote:
>>>
>>>> Hi Kyle,
>>>>
>>>> Thanks for the reply.
>>>>
>>>> The dataset is of 0.05 degree resolution, so that certainly isn't the
>>>> problem. I have attached an image of the same data, but limiting the
>>>> min/max lat/lon to the US Mid Atlantic. In this image you will see much
>>>> more detail. This is the type of detail I was hoping to achieve for the
>>>> entire globe. I figured if I increased the resolution of the global png, it
>>>> would create the desired effect, but as you can see from the global image I
>>>> attached, this wasn't the case.
>>>>
>>>> Looking forward to hearing your thoughts.
>>>> Thank you,
>>>>
>>>> Micah
>>>>
>>>>
>>>>
>>>> On Thu, Oct 30, 2014 at 12:26 PM, Kyle Griffin <ksgriffin2 at wisc.edu>
>>>> wrote:
>>>>
>>>>> Micah,
>>>>>
>>>>> This looks more like a limitation of your dataset - SST data is not of
>>>>> infinite resolution, and you're plotting far more pixels than would be data
>>>>> points in even a 0.1˚ dataset! It looks like the internal pixels are the
>>>>> same size as your coastlines, so I don't see an issue with NCL there. More
>>>>> specifically, you are not actually plotting coastlines - they only plot if
>>>>> you tell them to plot with a call to gsn_csm_map or another similar
>>>>> plotting tool. If you're looking for high resolution coastlines, look at
>>>>> the RANGS mapping capabilities in NCL. Beyond that, you can always plot
>>>>> shapefiles as well.
>>>>>
>>>>> Yes, vector images are going to be extremely large and painful for
>>>>> even a moderate resolution file over the full globe. When you say raster,
>>>>> are you talking about it in the image sense (non-vector file) or in the
>>>>> cnFillMode sense (RasterFill, AreaFill, etc.;
>>>>> https://www.ncl.ucar.edu/Document/Graphics/Resources/cn.shtml#cnFillMode)?
>>>>> Raster fill mode will make the data more blocky and reduce interpolation
>>>>> between points, but the trade-off is a much faster plotting of the image
>>>>> and works well for high-resolution datasets being plotted at relatively low
>>>>> resolution/wide zoom.
>>>>>
>>>>>
>>>>> Kyle
>>>>>
>>>>> ----------------------------------------
>>>>> Kyle S. Griffin
>>>>> Department of Atmospheric and Oceanic Sciences
>>>>> University of Wisconsin - Madison
>>>>> Room 1421
>>>>> 1225 W Dayton St, Madison, WI 53706
>>>>> Email: ksgriffin2 at wisc.edu
>>>>>
>>>>> On Thu, Oct 30, 2014 at 9:58 AM, Micah Sklut <micahs2005 at gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> This is a follow up to my previous posts, in reference to searching
>>>>>> for high resolution images that could be used as zooming/navigating
>>>>>> (specific interest is with image tile layers).
>>>>>>
>>>>>> I figured if I created a png file with a high resolution, it would be
>>>>>> able to capture the high detail, like with coastlines and so forth.
>>>>>> I've attached an image with very high resolution (16384x16384), but
>>>>>> as you can see, if you zoom the global image into the coastlines they are
>>>>>> extremely blocky.
>>>>>>
>>>>>> Is is possible to capture high resolution features, such as
>>>>>> coastlines in a global raster image with NCL?
>>>>>>
>>>>>> FYI, I tried the vector image route, but the file size was gigantic,
>>>>>> so that didn't seem like a proper route.
>>>>>>
>>>>>> Thank you,
>>>>>>
>>>>>> --
>>>>>> Micah Sklut
>>>>>>
>>>>>> _______________________________________________
>>>>>> ncl-talk mailing list
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>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Micah Sklut
>>>>
>>>>
>>>
>>
>>
>> --
>> Micah Sklut
>>
>>
>


-- 
Micah Sklut
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