[ncl-talk] station data/ ascii to nc/ subsetting problem

[Dennis Shea]

See attached script and png.

HTH, D

On Wed, Jan 2, 2019 at 8:32 PM Sam McClatchie <smcclatchie at fishocean.info>
wrote:

> Colleagues
>
> Thanks for pointing out the gc_inout function, Rick. My regions are
> currently simple shape files.
>
> The function gc_inout is working for me (please see test code and test
> data at
> <https://my.pcloud.com/publink/show?code=kZsanC7ZlKPCnfV5wnLFWm4C2yCww4mtUIYV>
> <https://my.pcloud.com/publink/show?code=kZsanC7ZlKPCnfV5wnLFWm4C2yCww4mtUIYV>).
> But now I have what I think is a simple problem that I have not solved. How
> to subset the data variables based on the logical variable produced by
> gs_inout? I have tried to do so using a looped conditional statement, but
> there is a problem with the indexed assignment as I have written it. I'm
> also expecting that a loop like this will be way to slow for the large data
> size I have. There must be a smarter way to do this, but in reading the
> manuals and help files, I'm still missing it.
>
> Any hints would be useful.
>
> Thanks, Sam
>
> On 28/12/18 2:44 AM, Rick Brownrigg wrote:
>
> Hi Sam,
>
> You might take a look at the gc_inout  function. Not sure how you are
> defining your regions - shapefiles? Simple bounding boxes?
>
> Rick
>
> On Tuesday, December 25, 2018, Sam McClatchie <smcclatchie at fishocean.info>
> wrote:
>
>> Colleagues
>>
>> I have some voluminous station data in ascii files that I have written
>> into a netcdf file with minimal pre-definition of dimensions and attributes
>> (please see the link below for the data and code). My problem is that I
>> want to subset the global fishing_hours variable conveniently by region.
>>
>> The obvious solution would be to dimension the fishing_hours variable
>> properly into a 3-dimensional variable (time, lat, lon) and use named
>> coordinate subscripting. I realised when I went back to rewrite the data
>> with variable pre-definition that I have a problem, because these data are
>> not on any kind of grid, so the sizes of the coordinate arrays are the same
>> size as the vector lengths for lat/ lon.
>>
>> My goal is to plot fishing_hours on maps where each point is colour-coded
>> by the magnitude of the fishing_hours variable (as for example, here: <see
>> https://www.ncl.ucar.edu/Applications/Scripts/station_2.ncl>). Note that
>> the data were not subset, I simply set the map regions. Also, the plot only
>> shows lat/lon variables, not the fishing_hours variable because it has no
>> coordinate variables.
>>
>> The data, NCL code, and figure referred to in this message can be
>> downloaded from here:
>> <https://my.pcloud.com/publink/show?code=kZsanC7ZlKPCnfV5wnLFWm4C2yCww4mtUIYV>
>> <https://my.pcloud.com/publink/show?code=kZsanC7ZlKPCnfV5wnLFWm4C2yCww4mtUIYV>
>> I suggest downloading the directory as an archive and unpacking it
>> locally to a scratch directory.
>>
>> Any help on how to conveniently subset the global fishing_hours data by
>> lat/ lon would be appreciated.
>>
>> Best fishes
>> Sam
>>
>
> --
> Sam McClatchie (fisheries oceanographer)
> & Elena Turin (accounting & auditing)
> FishOcean Enterprises
> 38 Upland Rd, Huia, Auckland 0604, New Zealand
> cell: 027 752 8495
> Internet <http://www.fishocean.info>
>
>
> "The time has come", the tui said,
> "to talk of many things:
> Of songs - and ferns - and flowering flax,
> of Pukekos and dreams ..."
>
> (not Lewis Carroll)
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