Perverse Inverse

COGO; short for coordinate geometry. Quite often when we are on site we need to do some quick on the hoof calculations, point to point distances or difference in height between two points already logged to the survey controller. I believe it is an American term that has come here through various software interfaces but to "inverse" is to do this calculation. Designing a pipeline an engineer standing over your shoulder may ask how far have we dropped between here and there and you can smugly tap a few buttons and say we have dropped 150m metres in about 700 metres.
Anyway for less scientific reasons I inversed my current position and where I had started from; a much higher point on the mountain side. Given I was working generally down hill I wanted to comfort (brace) my self with how much I would have to re-ascend to collect the rest of the gear and pack up.
Hastier than normal key presses told me 150 metres. My gut feeling had been half this height and my tired legs trembled looking back up the steep hill side. I repeated the calculation; clearly an errant key press earlier; sixty something this time. That's more like it.

But funnily I was now standing with my gaze firmly fixed on the daunting slope. It was still a horrid climb at the end of a long day regardless of what the inverse solution was. Did I really need to know?

This is a view close to my starting point and much of the land corridor surveyed follows the valley floor in the distance and round the bend where the track goes out of sight.