How to calculate grade

Does anyone have a code snippet to calculate grade for cycling? Everything that I have tried so far has been too wildly inaccurate to be useful.

Stanislav.Bures over 6 years ago

This is my solution, but question is how is it accurate..

class ClimbView extends Ui.DataField {

 function initialize() {
        DataField.initialize();
    }

 var prevV = new [5];
 var prevD = new [5];

 var vzdalenost5s = 0;
 var vyska5s = 0;

    function compute(info) {

 if(info.altitude != null) {

        if (prevV[0] != null && prevV[1] != null && prevV[2] != null && prevV[3] != null)
        {vyska5s = (info.altitude - prevV[3]);}
     else
     {vyska5s = 0;}

        if (prevV[0] == null) {
      prevV[0] = info.altitude;
     }
     else if (prevV[1] == null) {
        prevV[1] = info.altitude;
     }
     else if (prevV[2] == null) {
        prevV[2] = info.altitude;
     }
     else if (prevV[3] == null) {
        prevV[3] = info.altitude;
     }     
     else {
     prevV[3] = prevV[2];
     prevV[2] = prevV[1];
     prevV[1] = prevV[0];
     prevV[0] = info.altitude;
     }
 }

 if(info.elapsedDistance != null) {

        if (prevD[0] != null && prevD[1] != null && prevD[2] != null && prevD[3] != null)
        {vzdalenost5s = (info.elapsedDistance - prevD[3]);}
     else
     {vzdalenost5s = 0;}

        if (prevD[0] == null) {
      prevD[0] = info.elapsedDistance;
     }
     else if (prevD[1] == null) {
        prevD[1] = info.elapsedDistance;
     }
     else if (prevD[2] == null) {
        prevD[2] = info.elapsedDistance;
     }
     else if (prevD[3] == null) {
        prevD[3] = info.elapsedDistance;
     }     
     else {
     prevD[3] = prevD[2];
     prevD[2] = prevD[1];
     prevD[1] = prevD[0];
     prevD[0] = info.elapsedDistance;
     }     


    }
}

    function onUpdate(dc) {

    var width = dc.getWidth();
    var height = dc.getHeight();
   var barva1;
   var barva2;
   var barva3;
 var procenta = 0;

 if (vzdalenost5s != 0 && vyska5s != 0){
 procenta = (100 * vyska5s) / vzdalenost5s;
 }
 else{
 procenta = 0;}

 if(procenta >= 100){
 procenta = 0;}

        if (getBackgroundColor() == Gfx.COLOR_BLACK) {
  barva1 = Gfx.COLOR_BLACK;
  barva2 = Gfx.COLOR_WHITE;
  barva3 = Gfx.COLOR_LT_GRAY;
        } else {
  barva1 = Gfx.COLOR_WHITE;
  barva2 = Gfx.COLOR_BLACK;
  barva3 = Gfx.COLOR_DK_GRAY;
        }


        // pozadi
        dc.setColor(barva1, Gfx.COLOR_TRANSPARENT); 
        dc.fillRectangle(0, 0, width, height);



  dc.setColor(barva2, Gfx.COLOR_TRANSPARENT);
  dc.drawText(width/2, height/2, 7, procenta.format("%.01f") + "%" , Gfx.TEXT_JUSTIFY_CENTER | Gfx.TEXT_JUSTIFY_VCENTER);

  dc.setColor(barva3, Gfx.COLOR_TRANSPARENT);
  dc.drawText(width/2, 6, 0, "Climb" , Gfx.TEXT_JUSTIFY_CENTER | Gfx.TEXT_JUSTIFY_VCENTER);
   
      }

}

jgpallero over 6 years ago

Does anyone have a code snippet to calculate grade for cycling? Everything that I have tried so far has been too wildly inaccurate to be useful.

Here (https://forums.garmin.com/forum/deve...41#post1280941, and in the rest of the thread) I explain my approximation to the problem. The method is still not fully tested, and I think it consumes too much battery due the computations, but you can find the code here: https://bitbucket.org/jgpallero/pvv. When the 2.4 version of the SDK runs on Edge 520 I'll try to use the atmospheric pressure instead of Activity::altitude data to compute the slope

DaveBrillhart 2 months ago in reply to Stanislav.Bures

I'm going to solve this enigma. Here is my current test field as I work on all the conditions needed to handle grade noise and delay. I expect to finalize this over the next few weeks. My primary device is an EDGE 1050, but I also have an EDGE 1030 and Forerunner 955 to test on, which should cover most of the barometric sensor types out there - which is the cause of most of the issues. https://apps.garmin.com/apps/f0ddadf0-4eb1-41fc-ae62-3b94575109ab