Re: syntax for creating array for data fordata from ascii file

There is only one file. The first column is contains timesteps of an entire
month. What if I don't want to specify the lon array or the time array as
you have here....I just want NCL to read it straight from the file so that
there is no guessing?

On 12/8/08 1:28 PM, "Adam Phillips" <asphilli_at_cgd.ucar.edu> wrote:

> Hi Erik,
> I think you're getting the coordinate variable assignments and the data
> array entry confused. First, set up coordinate arrays for time and
> longitude:
>
> (These are just guesses on my part..)
> time = ispan(0,10,1)
> lon = fspan(-20,294.5,630) ; go from 20W->294.5E by 0.5
>
> arr = new((/dimsizes(time),dimsizes(lon)/),"float",-999.)
> arr!0 = "time"
> arr&time = time
> arr!1 = "lon"
> arr&lon = lon
>
> Next, you need to read in the ascii data into the array correctly. Note
> that the syntax of your time (2006:09:01) will be read in to asciiread
> as three different entries. Thus, your data should be read in as 5
> columns and 630 rows.
>
> data = asciiread("data.asc",(/630,5/),"float")
> file_year = data(:,0)
> file_month = data(:,1)
> file_day = data(:,2)
> file_lon = data(:,3)
> file_data = data(:,4)
> delete(data)
>
> Here is were it can get tricky. If each ascii file contains one
> timestep, then it's easy:
>
> do gg = 0,dimsizes(file_data)-1
> arr(0,{file_lon(gg)})=(/file_data(gg)/) ; data entry for 0th timestep
> end do
>
> Notice that I am using coordinate subscripting to enter the data into
> the correct longitude slot.
>
> If each ascii file has multiple timesteps, you will have to design the
> do loop to recognize that when the time index has changed and put the
> data into the correct time slot of the arr data array.
>
> This should at least get you started..
> Adam
>
> Erik Noble wrote:
>> Hi. Could I have some help here with a simple question? I just want to
>> make sure that I am getting the syntax right for using data from an
>> ascii file to create and array. I keep running into problems.
>> I have an ascii file that is three columns -" time", "longitude", and
>> "rainfall amount (mm)", and 630 rows.
>> 2006:09:01 -20.000 11.3280
>> 2006:09:01 -19.500 12.2291
>> . . .
>> . . .
>> . . .
>>
>> I am trying to create a time vs. longitude plot (hovmoller) which
>> requires that data be 2 dimensional with longitude as the the right-most
>> dimension.
>> To correctly read in this data into an array "rain" would be the following?
>> rain = new((/2/630/),float)
>> rain(0,:)=data(:,0) ; to read in time
>> rain(1,:)=data(:,1) ; to read in lon
>>
>> The next step would be to just plot the data
>>
>> plot = gsn_csm_hov(wks, rain, res )
>>
>>
>> Where do the actual "rainfall amount" rainfall amount values go if I
>> have already "filled" in the dimensions for time and longitude? Just
>> trying to understand the concept and what else I need to do.
>> Thank you for your time.
>> -Erik
>>
>>
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>>
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Received on Mon Dec 08 2008 - 11:56:13 MST