Extract daily time series NetCDF to specific location

Hi,

I want to extarct daily time series but it doesn't work. The reasons are; (1) it seems like time matrix is minus and (2) it seems like time matrix exceeds array bounds (must not exceed 365) and (3) empty metrix after extraction. Link for data is ftp://ftp.cdc.noaa.gov/Datasets/cpc_global_precip/precip.2019.nc

Code is as folliwings;

clc
close all
clear all
filename = ('precip.2019.nc');
info = ncinfo(filename);
unitsTime = info.Variables(3).Attributes(2);
unitsPrep = info.Variables(4).Attributes(2).Value;
validRangePrep = info.Variables(4).Attributes(9).Value;
labelPrep = info.Variables(4).Attributes(7).Value;
time = ncread(filename,'time');
prep = ncread(filename,'precip'); 
lon = double(ncread(filename,'lon'));
lat = double(ncread(filename,'lat'));
location_lat = knnsearch(lat,18.5);
location_lon = knnsearch(lon,102.5);
tDatenum = datenum('01-01-2019 00:00:00','dd-mm-yyyy HH:MM:SS');
from_date = '01-01-2019 00:00:00'; to_date = '31-12-2019 00:00:00';
idxDatenum = from_date <= tDatenum & tDatenum <= to_date;
myPrepData = squeeze(prep(location_lon,location_lat,idxDatenum));

Thanks in advance.

Phat

Answer 1

[Meg Noah]

Here's a solution:

clc
close all
clear all
filename = ('precip.2019.nc');
info = ncinfo(filename);

% Variable 1
lat = double(ncread(filename,'lat'));

% Variable 2
lon = double(ncread(filename,'lon'));

% Variable 3
% data are for each day of the year (2019)
time = ncread(filename,'time');
unitsTime = info.Variables(3).Attributes(2).Value;
fprintf(1,'Time Units: %s\n',unitsTime);
tDatenum = datenum(1900,1,1,time,0,0);

% Variable 4
prep = ncread(filename,'precip'); 
prepMissingValue = info.Variables(4).Attributes(1).Value;
prepUnits = info.Variables(4).Attributes(2).Value;
prepDescription = info.Variables(4).Attributes(3).Value;

% validRangePrep = info.Variables(5).Attributes(8).Value;
labelPrep = info.Variables(4).Attributes(7).Value;
validRangePrep = info.Variables(4).Attributes(10).Value;

% location_lat = knnsearch(lat,18.5);
% location_lon = knnsearch(lon,102.5);
dist = abs(lat - 18.5);
idxLat = find(dist == min(dist));
dist = abs(lon - 102.5);
idxLon = find(dist == min(dist));

% print out locations found
nsites = length(idxLat)*length(idxLon);
fprintf(1,'Found %d locations near site\n',nsites);
for kLat = 1:length(idxLat)
    for kLon = 1:length(idxLon)
         fprintf(1,'Location: Lat = %f Lon = %f\n', lat(idxLat(kLat)), lon(idxLon(kLon)));
    end
end

% hardwiring getting all 4 sites
DOY = 1:365; DOY = DOY';
GlobalDaily = table(DOY);
GlobalDaily.Site1 = squeeze(prep(idxLon(1),idxLat(1),:));
GlobalDaily.Site2 = squeeze(prep(idxLon(1),idxLat(2),:));
GlobalDaily.Site3 = squeeze(prep(idxLon(2),idxLat(1),:));
GlobalDaily.Site4 = squeeze(prep(idxLon(2),idxLat(2),:));
GlobalDaily.Properties.VariableUnits = {'Day Of Year','mm','mm','mm','mm'};
GlobalDaily.Properties.UserData.Site1 = [lat(idxLat(1)), lon(idxLon(1))];
GlobalDaily.Properties.UserData.Site2 = [lat(idxLat(2)), lon(idxLon(1))];
GlobalDaily.Properties.UserData.Site3 = [lat(idxLat(1)), lon(idxLon(2))];
GlobalDaily.Properties.UserData.Site4 = [lat(idxLat(2)), lon(idxLon(2))];
GlobalDaily.Properties.UserData.Description = {info.Variables(4).Attributes.Value}';

strSite1 = ['Site1 = ' ...
    num2str(GlobalDaily.Properties.UserData.Site1(1)) ...
    ' \circN, ' ...
     num2str(GlobalDaily.Properties.UserData.Site1(2)) ' \circE'];
strSite2 = ['Site2 = ' ...
    num2str(GlobalDaily.Properties.UserData.Site2(1)) ...
    ' \circN, ' ...
     num2str(GlobalDaily.Properties.UserData.Site2(2)) ' \circE'];
strSite3 = ['Site3 = ' ...
    num2str(GlobalDaily.Properties.UserData.Site3(1)) ...
    ' \circN, ' ...
     num2str(GlobalDaily.Properties.UserData.Site3(2)) ' \circE'];
strSite4 = ['Site4 = ' ...
    num2str(GlobalDaily.Properties.UserData.Site4(1)) ...
    ' \circN, ' ...
     num2str(GlobalDaily.Properties.UserData.Site4(2)) ' \circE'];
 
figure('color','white','Position',[70 500 1200 450]);
set(gca,'fontname','Ariel','fontsize',14,'fontweight','bold');
hold on
box on
plot(GlobalDaily.DOY,GlobalDaily.Site1,'DisplayName',strSite1);
plot(GlobalDaily.DOY,GlobalDaily.Site2,'DisplayName',strSite2);
plot(GlobalDaily.DOY,GlobalDaily.Site3,'DisplayName',strSite3);
plot(GlobalDaily.DOY,GlobalDaily.Site4,'DisplayName',strSite4);
legend('location','best');
ylabel([labelPrep ' [' prepUnits ']']);
title({'CPC Global Precip RT: Daily total of precipitation'; ...
    'Surface Measurements'});
xlim([0 365]);
% tickmarks at first day of each month
ttt = datenum(2020,1:12,1,0,0,0);
ttt = ttt - ttt(1) + 1;
set(gca,'xtick',ttt);
set(gca,'xticklabel',{'Jan','Feb','Mar','Apr','May','Jun','Jul','Aug', ...
    'Sep','Oct','Nov','Dec'});

[Augusto Gabriel da Costa Pereira]

78 / 5.000

Resultados de tradução

this error appears on mine:

The index exceeds the number of array elements (7).