Downloading weather files from a server

Hello

I am working on a project where i need to periodically download weather forecasts from a server. I have been experimenting with the urlread() and urlwrite() functions which is easy enough. The problem is that the url for the file includes date and time of submission. So i would like to download the most recent files.

an example url: http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/2012-01-07T09-30-02Z_FPTO51.0_r1101_CC.csv

where the date and time portion changes. How can i specify a url such that i will get the most recent copy?

Answer 1

[Walter Roberson]

If you urlread() on http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/ then you could pick out the most recent file.

[alexander]

ok i have that done. It's kind of dirty but it works. I did this:

clear all

clc

current_files=urlread('http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/');

relev_files=strfind(current_files,'FPTO11.0_r1124_TA.csv');

%for most recent file use last index in relev_files

ta_url=['http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/',current_files(relev_files(1:end)-21:relev_files(1:end)+20)];

ta_data=urlread(ta_url)

Now i want to format this data into a matrix.

i was going use character location relative to the comma and then use num2str() but this does not work on the right side of the comma. How can i specify the end of a line?

I tried (ta_data(6:\n) but this does not work.

[Abdul]

I have worked on this and put the data in the separate matrices

 close all, clear all, clc 

 %%download weather forecast data from server
 current_files=urlread('http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/');
 relev_files=strfind(current_files,'FPTO51.0_r1101_TA.csv');
 %for most recent file use last index in relev_files 
 ta_url=['http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/',current_files(relev_files(1:end)-21:relev_files(1:end)+20)];
 % ta_url=['http://dd.weatheroffice.ec.gc.ca/meteocode/ont/csv/',current_files(relev_files(1:end)-21:relev_files(1:end)+20)];
 ta_data=urlread(ta_url)

 %%put forecast data into vectors
 clc
 C = [strsplit(ta_data, '\n')]' ;

 D = char(C(2:end-1));

 for I = 1:length(D)
    E = strsplit(D(I,:), '-');

    year(I) = str2num(char(E(1,1)));
    month(I) = str2num(char(E(1,2)));

    F = char(E(1,3));
    G = strsplit(F, 'T');

    day(I) = str2num(char(G(1,1)));

    H = char(G(1,2));
    J = strsplit(H, ':');

    hour(I) = str2num(char(J(1,1)));
    min(I) = str2num(char(J(1,2)));

    K = char(J(1,3));
    L = strsplit(K, 'Z');

    sec(I) = str2num(char(L(1,1)));

    M = char(L(1,2));
    N = strsplit(M, ',');

    value(I) = str2num(char(N(1,2)));

 end
 % F = strsplit(D(1,:), 'T')
 [year' month' day' hour' min' sec' value']
 figure
 t = datetime(year, month, day, hour, min, sec);
 plot(t, value, '*')
 hold on
 plot(t, value, '-k', 'Linewidth', 2)
 axis tight, grid minor
 xlabel('Time')
 ylabel('Temperature (°C)')