On trails that drop below sea level, like Sugar Trail the trail data below sea level shows as if it's all flat land. (At the bottom it's -230m below sea level)
So did some looking at the code, Its not a problem with the elevation chart, the actual data has all those points at 0.9m. So the actual trail gps altitude data is wrong. I also looked at my function to get elevation data from Google API, I don't modify it in a way to make it above zero. So its either the source gps data is like this, or Google Elevation API has it wrong.
Can you email me an original gps file for this trail.