Re: Binning point data into lat-lon grid for 2D frequency/density plots

I used bogus data and generated Example 2 at

    http://www.ncl.ucar.edu/Applications/binning.shtml

Cheers

On 11/10/12 1:12 PM, Dennis Shea wrote:
> No matter what, I think you must define the grid.
>
> I think you could use
> http://www.ncl.ucar.edu/Document/Functions/Built-in/bin_sum.shtml
> Just use the count that is returned. A complicated example of
> use is at http://www.ncl.ucar.edu/Applications/binning.shtml
>
> However, I have attached an untested script that does what you want.
> You must read in the data ...
>
> On 11/9/12 3:13 PM, Colin Zarzycki wrote:
>> Hello,
>>
>> I'm attempting to generate track density plots for tropical cyclones
>> (i.e., the number of times/frequency a tropical cyclone passes over a
>> given location within the global domain). Essentially a 2-D histogram.
>> Here is a rough example of what I'd like to do:
>> http://mpo581-hw2.wikispaces.com/file/view/colbert_tdall.jpeg/206350210/colbert_tdall.jpeg
>>
>>
>> I have generated two arrays:
>>
>> cyclone_lat(:)
>> cyclone_lon(:)
>>
>> which for a given ith value, provides the corresponding lat/lon
>> location of a specific tropical cyclone at a given time. What I'm
>> interested in doing is generating a lat-lon bin grid and then
>> incrementing the count of each bin every time I have a cyclone lat/lon
>> which falls in that bin's "domain."
>>
>> The only way I have been able to see doing this is generating a large
>> zeros matrix and then for each ith value of cyclone_lat and
>> cyclone_lon looping over the matrix until it finds the closest lat-lon
>> pair and incrementing that bin's value by 1, although that would seem
>> to require array reshaping and a lot of seemingly unnecessary loops
>> for large data sets.
>>
>> So before starting that I figured I'd dig around - I wasn't able to
>> find a similar example on the webpage, but is there a function or
>> feature that takes point data and accumulates it onto a spatial grid
>> in this fashion that would be more efficient than the above proposal?
>>
>> Apologies in advance if this is a simpleton question!
>>
>> Cheers,
>>
>> -Colin
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Received on Mon Nov 12 11:34:38 2012