average-time-connected-surface-300s.mlx

%{
  This is supplementary data visualization script
  to an application the is sampling analog input A0 of ESP8266
  so it then can be displayed on-line in a web browser
  Application consists of several files
  Please check repository below for details

  Repository: https://github.com/krzychb/EspScopeA0
  Version: Bravo
  File: average-time-connected-surface-300s.mlx
  Revision: 0.1.0
  Date: 27-Sep-2016
  Author: krzychb at gazeta.pl

  Copyright (c) 2016 Krzysztof Budzynski. All rights reserved.

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
%}


%% Data Input Parameters %%
readChannelID = 153983; % enter your Channel ID
readAPIKey = 'U6GWWLQRMQYPTPII'; % enter your Read API Key
dateRange = [datetime('11-Sep-2016 15:00:00'), datetime('now')]; % enter the date and time your data starts

%% Read Data %%
SamplingPause = thingSpeakRead(readChannelID, 'Field', 7, 'DateRange', dateRange, 'ReadKey', readAPIKey);
NumberOfSamples = thingSpeakRead(readChannelID, 'Field', 8, 'DateRange', dateRange, 'ReadKey', readAPIKey);
TimeConnected = thingSpeakRead(readChannelID, 'Field', 5, 'DateRange', dateRange, 'ReadKey', readAPIKey);


%% Agregate Results %%
% megre Sampling Pause and Number of Samples into an array
allXY = [SamplingPause, NumberOfSamples];

% select all unique pairs of Sampling Pause and Number of Samples
[unXY, unXY_idx, unXY_ord] = unique(allXY, 'rows');

% calculate the mean (average) of Time Connected
meanT = accumarray(unXY_ord, TimeConnected, [], @mean);

% from the unique pairs extract column containg Sampling Pause
X = unXY(:, 1);
% ...  and then Number of Samples
Y = unXY(:, 2);


%% Show Results %%
% select unique values of Sampling Pause and Number of Samples
unX = unique(SamplingPause);
unY = unique(NumberOfSamples);

% double the number of points for Sampling Pause
j = 1;
for i = 2:length(unX)
  nX(j) = unX(i-1);
  j = j + 1;
  nX(j) = (unX(i-1) + unX(i)) / 2;
  j = j + 1;
end

% double the number of points for Number of Samples
j = 1;
for i = 2:length(unY)
  nY(j) = unY(i-1);
  j = j + 1;
  nY(j) = (unY(i-1) + unY(i)) / 2;
  j = j + 1;
end

% create a mesh grid
[XI, YI] = meshgrid(nX, nY);

% calculate grid data
ZI = griddata(X, Y, meanT, XI, YI);
% show 3d surface chart
surf(XI, YI, ZI, 'FaceColor','interp','linestyle', 'none');
% add labels
title('Average Time Connected [s]')
xlabel('Sampling Pause [ms]');
ylabel('Number of Samples');
zlabel('Time Connected [s]');

% add color legend
colorbar('Location', 'EastOutside')