added quadrantAnalysis()

Author: adriangibbons

README.md

@@ -286,10 +286,11 @@ $pFFA->hrMetrics($hr_resting, $hr_maximum, $hr_FT, $gender);
  * Intensity Factor
 
 ###Power
-Two functions exist for analysing power data:
+Three functions exist for analysing power data:
 ```php
 $pFFA->powerMetrics($functional_threshold_power);  // e.g. 312
 $pFFA->criticalPower($time_periods);  // e.g. 300 or [300, 600, 900, 1200]
+$pFFA->quadrantAnalysis($crank_length, $ftp, $selected_cadence);  // Crank length in metres; cadence defaults to 90rpm if not supplied
 ```
 **Power metrics:**
  * Average Power
@@ -303,6 +304,9 @@ $pFFA->criticalPower($time_periods);  // e.g. 300 or [300, 600, 900, 1200]
 
 Note that ```$pFFA->criticalPower``` and some power metrics (Normalised Power, Variability Index, Intensity Factor, Training Stress Score) will use the [PHP Trader](http://php.net/manual/en/book.trader.php) extension if it is loaded on the server. If the extension is not loaded then it will use the built-in Simple Moving Average algorithm, which is far less performant particularly for larger files!
 
+**Quadrant Analysis** provides insight into the neuromuscular demands of a bike ride through comparing pedal velocity with force by looking at cadence and power.
+![Mountain Biking](demo/img/quadrant-analysis.jpg)
+
 A demo of power analysis is available [here](http://www.adriangibbons.com/php-fit-file-analysis/demo/power-analysis.php).
 
 ##Other methods

demo/img/quadrant-analysis.jpg

@@ -11,8 +11,8 @@
     $file = '/fit_files/power-analysis.fit';
 
     $options = [
-    //		'fixData' => ['all'],
-        'units' => ['metric']
+    //	  'fixData' => ['all'],
+    //    'units' => ['metric']
     ];
     $pFFA = new adriangibbons\phpFITFileAnalysis(__DIR__ . $file, $options);
 
@@ -28,13 +28,15 @@
         $date_s = $date_s + $json_tz->rawOffset + $json_tz->dstOffset;
     }
     $date->setTimestamp($date_s);
-        
+    
+    $ftp = 329;
     $hr_metrics = $pFFA->hrMetrics(52, 185, 172, 'male');
-    $power_metrics = $pFFA->powerMetrics(312);
+    $power_metrics = $pFFA->powerMetrics($ftp);
     $criticalPower = $pFFA->criticalPower([2,3,5,10,30,60,120,300,600,1200,3600,7200,10800,18000]);
     $power_histogram = $pFFA->powerHistogram();
-    $power_table = $pFFA->powerPartioned(312);
-    $power_pie_chart = $pFFA->partitionData('power', $pFFA->powerZones(312), true, false);
+    $power_table = $pFFA->powerPartioned($ftp);
+    $power_pie_chart = $pFFA->partitionData('power', $pFFA->powerZones($ftp), true, false);
+    $quad_plot = $pFFA->quadrantAnalysis(0.175, $ftp);
 } catch (Exception $e) {
     echo 'caught exception: '.$e->getMessage();
     die();
@@ -152,6 +154,16 @@
           </div>
         </div>
       </div>
+      
+      <div class="panel panel-default">
+        <div class="panel-heading">
+          <h3 class="panel-title"><i class="fa fa-line-chart"></i> Quadrant Analysis <small>Circumferential Pedal Velocity (x-axis) vs Average Effective Pedal Force (y-axis)</small></h3>
+        </div>
+        <div class="panel-body">
+          <div id="quadrant_analysis" style="width:100%; height:600px"></div>
+        </div>
+      </div>
+      
     </div>
   </div>
 </div>
@@ -370,6 +382,108 @@ function labelFormatter(label, series) {
       $("#power_zones_table tr").removeClass("danger");
       $("#" + obj.series.data[0][1].toFixed(1).toString().replace(/\./g, '-') ).addClass("danger");
     });
+    
+var quad = [<?php    
+$plottmp = [];
+foreach ($quad_plot['plot'] as $v) {
+	$plottmp[] = '[' . $v[0] . ', ' . $v[1] . ']';
+}
+echo implode(', ', $plottmp); ?>];
+    
+    var lo = [<?php
+unset ($plottmp);
+$plottmp = [];
+foreach ($quad_plot['ftp-25w'] as $v) {
+    $plottmp[] = '[' . $v[0] . ', ' . $v[1] . ']';
+}
+echo implode(', ', $plottmp); ?>];
+
+    var at = [<?php
+unset ($plottmp);
+$plottmp = [];
+foreach ($quad_plot['ftp'] as $v) {
+    $plottmp[] = '[' . $v[0] . ', ' . $v[1] . ']';
+}
+echo implode(', ', $plottmp); ?>];
+    var hi = [<?php
+unset ($plottmp);
+$plottmp = [];
+foreach ($quad_plot['ftp+25w'] as $v) {
+    $plottmp[] = '[' . $v[0] . ', ' . $v[1] . ']';
+}
+echo implode(', ', $plottmp); ?>];
+    
+    var markings = [
+      {
+        color: "black",
+        lineWidth: 1,
+        xaxis: {
+          from: <?php echo $quad_plot['cpv_threshold']; ?>,
+          to: <?php echo $quad_plot['cpv_threshold']; ?>
+        }
+      },
+      {
+        color: "black",
+        lineWidth: 1,
+        yaxis: {
+          from: <?php echo $quad_plot['aepf_threshold']; ?>,
+          to: <?php echo $quad_plot['aepf_threshold']; ?>
+        }
+      }
+    ];
+    
+    var quadrant_analysis_options = {
+      xaxis: {
+        label: 'circumferential pedal velocity',
+        tickFormatter: function(label, series) { return label + ' m/s'; }
+      },
+      yaxis: {
+        max: 400,
+        label: 'average effective pedal force',
+        tickSize: 50,
+        tickFormatter: function(label, series) {
+          if(label == 0) return "";
+          return label + ' N';
+        }
+      },
+      grid: {
+        borderWidth: {
+          top: 0,
+          right: 0,
+          bottom: 0,
+          left: 0
+        },
+        markings: markings
+      },
+      legend: { show: false }
+    };
+    
+    var plot_qa = $.plot($("#quadrant_analysis"), [
+        {
+            data : quad,
+            points : { show: true, radius: 0.25, fill : true, fillColor: "#058DC7" }
+        },
+        {
+            data : at,
+            color: "blue",
+            lines: { show: true, lineWidth: 0.5 }
+        },
+        {
+            data : lo,
+            color: "red",
+            lines: { show: true, lineWidth: 0.5 }
+        },
+        {
+            data : hi,
+            color: "green",
+            lines: { show: true, lineWidth: 0.5 }
+        }
+    ], quadrant_analysis_options);
+    
+    $("#quadrant_analysis").append("<span style='background-color: #fafafa; top: " + (plot_qa.height() / 2 - 40) + "px; color: #333; text-align: center; font-size: 12px; border: 1px solid #ddd; border-radius: 5px; padding: 3px 7px; position: absolute; left: " + (plot_qa.width() - 140) + "px'><strong>High Force / High Velocity</strong><br><?php echo $quad_plot['quad_percent']['hf_hv']; ?> %</span>");
+    $("#quadrant_analysis").append("<span style='background-color: #fafafa; top: " + (plot_qa.height() / 2 - 40) + "px; color: #333; text-align: center; font-size: 12px; border: 1px solid #ddd; border-radius: 5px; padding: 3px 7px; position: absolute; left: 50px'><strong>High Force / Low Velocity</strong><br><?php echo $quad_plot['quad_percent']['hf_lv']; ?> %</span>");
+    $("#quadrant_analysis").append("<span style='background-color: #fafafa; top: " + (plot_qa.height() / 2 + 15) + "px; color: #333; text-align: center; font-size: 12px; border: 1px solid #ddd; border-radius: 5px; padding: 3px 7px; position: absolute; left: 50px'><strong>Low Force / Low Velocity</strong><br><?php echo $quad_plot['quad_percent']['lf_lv']; ?> %</span>");
+    $("#quadrant_analysis").append("<span style='background-color: #fafafa; top: " + (plot_qa.height() / 2 + 15) + "px; color: #333; text-align: center; font-size: 12px; border: 1px solid #ddd; border-radius: 5px; padding: 3px 7px; position: absolute; left: " + (plot_qa.width() - 140) + "px'><strong>Low Force / High Velocity</strong><br><?php echo $quad_plot['quad_percent']['lf_hv']; ?> %</span>");
   });
 </script>
 </body>

demo/power-analysis.php

@@ -8,8 +8,9 @@
  * Adrian Gibbons, 2015
  * Adrian.GitHub@gmail.com
  *
- * G Frogley edits, June 2016
- * Added code to generate TRIMPexp and hrIF (Intensity Factor) value to measure session if Power is not present
+ * G Frogley edits:
+ * Added code to generate TRIMPexp and hrIF (Intensity Factor) value to measure session if Power is not present (June 2015).
+ * Added code to generate Quadrant Analysis data (September 2015).
  *
  * https://github.com/adriangibbons/phpFITFileAnalysis
  * http://www.thisisant.com/resources/fit
@@ -1851,6 +1852,75 @@ public function isPaused()
         return $is_paused;
     }
 
+    /**
+     * Returns an array that can be used to plot Circumferential Pedal Velocity (x-axis) vs Average Effective Pedal Force (y-axis).
+     * NB Crank length is in metres.
+     */
+    public function quadrantAnalysis($crank_length, $ftp, $selected_cadence = 90)
+    {
+        if (!isset($this->data_mesgs['record']['power'])) {
+            throw new \Exception('phpFITFileAnalysis->quadrantAnalysis(): power data not present in FIT file!');
+        }
+        if (!isset($this->data_mesgs['record']['cadence'])) {
+            throw new \Exception('phpFITFileAnalysis->quadrantAnalysis(): cadence data not present in FIT file!');
+        }
+        
+        $quadrant_plot = [];
+        $quadrant_plot['selected_cadence'] = $selected_cadence;
+        $quadrant_plot['aepf_threshold'] = round(($ftp * 60) / ($selected_cadence * 2 * pi() * $crank_length), 3);
+        $quadrant_plot['cpv_threshold'] = round(($selected_cadence * $crank_length * 2 * pi()) / 60, 3);
+        
+        // Used to calculate percentage of points in each quadrant
+        $quad_percent = ['hf_hv' => 0, 'hf_lv' => 0, 'lf_lv' => 0, 'lf_hv' => 0];
+        
+        // Filter zeroes from cadence array (otherwise !div/0 error for AEPF)
+        $cadence = array_filter($this->data_mesgs['record']['cadence']);
+        $cpv = $aepf = 0.0;
+        
+        foreach ($cadence as $k => $c) {
+            $p = isset($this->data_mesgs['record']['power'][$k]) ? $this->data_mesgs['record']['power'][$k] : 0;
+            
+            // Circumferential Pedal Velocity (CPV, m/s) = (Cadence × Crank Length × 2 × Pi) / 60
+            $cpv = round(($c * $crank_length * 2 * pi()) / 60, 3);
+            
+            // Average Effective Pedal Force (AEPF, N) = (Power × 60) / (Cadence × 2 × Pi × Crank Length)
+            $aepf = round(($p * 60) / ($c * 2 * pi() * $crank_length), 3);
+            
+            $quadrant_plot['plot'][] = [$cpv, $aepf];
+            
+            if ($aepf > $quadrant_plot['aepf_threshold']) {  // high force
+                if ($cpv > $quadrant_plot['cpv_threshold']) {  // high velocity
+                    $quad_percent['hf_hv']++;
+                } else {
+                    $quad_percent['hf_lv']++;
+                }
+            } else {  // low force
+                if ($cpv > $quadrant_plot['cpv_threshold']) {  // high velocity
+                    $quad_percent['lf_hv']++;
+                } else {
+                    $quad_percent['lf_lv']++;
+                }
+            }
+        }
+        
+        // Convert to percentages and add to array that will be returned by the function
+        $sum = array_sum($quad_percent);
+        foreach ($quad_percent as $k => $v) {
+            $quad_percent[$k] = round($v / $sum * 100, 2);
+        }
+        $quadrant_plot['quad_percent'] = $quad_percent;
+        
+        // Calculate CPV and AEPF for cadences between 20 and 150rpm at and near to FTP
+        for ($c = 20; $c <= 150; $c += 5) {
+            $cpv = round((($c * $crank_length * 2 * pi()) / 60), 3);
+            $quadrant_plot['ftp-25w'][] = [$cpv, round((($ftp - 25) * 60) / ($c * 2 * pi() * $crank_length), 3)];
+            $quadrant_plot['ftp'][] = [$cpv, round(($ftp * 60) / ($c * 2 * pi() * $crank_length), 3)];
+            $quadrant_plot['ftp+25w'][] = [$cpv, round((($ftp + 25) * 60) / ($c * 2 * pi() * $crank_length), 3)];
+        }
+        
+        return $quadrant_plot;
+    }
+    
     /**
      * Outputs tables of information being listened for and found within the processed FIT file.
      */