Merge branch '3-add-SLTAC-matlab' into 'master'

Resolve "Add Matlab Example for SLTAC"

Closes #3

See merge request !8

.gitignore

 .ipynb_checkpoints/
+*.nc
+*.mat

example_07_SLTAC_monthly_mean_uv_off_Brazil.m

+% calculate monthly mean surface geostrophic velocity off Brazil from 2000-2017
+
+clear all
+close all
+
+% define path to data
+base_path = '/data/c2/TMdata/git_geomar_de_data/SLTAC_GLO_PHY_L4_REP/';
+SLTAC_version = 'v1.x.x';
+path_to_data = [base_path, SLTAC_version, '/data/'];
+
+% find indices of the region
+lat_lim = [-12 -4];
+lon_lim = [-40 -30] + 360;
+lat_nc = -89.875 : 0.25 : 89.875;
+lon_nc = 0.125 : 0.25 : 359.875;
+idx = find(lon_nc > lon_lim(1) & lon_nc < lon_lim(2));
+idy = find(lat_nc > lat_lim(1) & lat_nc < lat_lim(2));
+
+% choose time period
+year_folder = [2000 : 2017];
+
+% allocate monthly fields
+u_geo_m = NaN(length(idx), length(idy), length(year_folder) * 12);
+v_geo_m = u_geo_m;
+time_m = NaN(length(year_folder) * 12, 1);
+
+% initialize progressbar
+h = waitbar(0, 'Loading and averaging ...');
+
+% load all files of one month and average
+for iy = 1 : length(year_folder)
+
+    % find all data files for current year (determined by iy)
+    filename_year = [path_to_data, num2str(year_folder(iy))];
+    KK = dir(filename_year);
+    KK = KK(3 : end);
+
+    % for all file names, extract months from file name
+    for id = 1 : length(KK)
+        mm(id) = str2num(KK(id).name(29 : 30));
+    end
+
+    % for all months, find files for this month and average
+    for im = 1:12
+        kk = find(mm == im); % returns indices matching current month
+
+        % allocate temporary data fields
+        u_geo = NaN(length(idx),length(idy),length(kk));
+        v_geo = u_geo;
+
+        % load all files for current month
+        for ik = 1:length(kk)
+            filename_current_day = [filename_year, '/', KK(kk(ik)).name];
+
+            time_vec(ik) = double(ncread(filename_current_day, 'time'));
+            time_vec(ik) = time_vec(ik) + datenum(1950, 1, 1, 0, 0, 0);
+
+            ugos = double(ncread(filename_current_day, 'ugos'));
+            u_geo(:,:,ik) = ugos(idx, idy);
+
+            vgos = double(ncread(filename_current_day, 'vgos'));
+            v_geo(:,:,ik) = vgos(idx, idy);
+        end
+
+        % average and store in final arrays
+        u_geo_m(:, :, (iy - 1) * 12 + im) = nanmean(u_geo, 3);
+        v_geo_m(:, :, (iy - 1) * 12 + im) = nanmean(v_geo, 3);
+        time_m((iy - 1) * 12 + im) = nanmean(time_vec);
+
+        % update status bar
+        waitbar(((iy - 1) * 12 + im) / (length(year_folder) * 12), h)
+    end
+    clear mm KK
+end
+
+% close status bar
+close(h)
+
+% save as matfile
+lon = lon_nc(idx) - 360;
+lat = lat_nc(idy);
+time_vec = time_m;
+ugeo_mon = u_geo_m;
+vgeo_mon = v_geo_m;
+save example_07_SLTAC_monthly_mean_uv_off_Brazil lon lat time_vec ugeo_mon vgeo_mon
+
+% and plot
+figure(1);
+m_proj('mercator', 'long', [-40 -30], 'lat', [-12 -4]);
+hold on
+m_contourf( ...
+    lon_nc(idx) - 360, lat_nc(idy), nanmean(u_geo_m, 3)', ...
+    [-.5 : 1 / 63 : .5], 'edgecolor', 'none')
+m_gshhs_h('patch', [.5 .5 .5]);
+colorbar
+saveas(gcf, 'example_07_SLTAC_monthly_mean_uv_off_Brazil.png', 'png')