Tetrad Bashing

Continuing on from yesterday's post, this week I have been mostly scribbling all over my North Skye OS map and have now plotted my 5MR, broken down into tetrad level. If you're none too sure of what a tetrad is, or how they are numbered, have a look at this BTO webpage which explains how to read co-ordinates on an OS map, what a monad, tetrad and 100km square are, what DINTY means and how they each fit into the national grid system. I know that nowadays everybody, including the emergency services, rants on about what3words, but for survey work in the field you really do need to use established, plottable co-ordinates. Plus an OS map won't run out of power halfway up a mountain and leave you bumbling along clueless as to precisely where you are.

Here's what my 5MR looks like drawn onto an OS map

Try to ignore the outer arc

I started drawing the circumference of my 5MR and suddenly realised it seemed somewhat larger than expected. Looking at the scale bar, I soon discovered my error - I was using nautical miles instead of land miles, doh! I haven't managed to find an eraser yet (do they even exist outside of school equipment stores?) (Actually, do they even use pencils in schools nowadays???) so the outer arc stays for the time being. I would use a bit of bread, but it's quite a lot of pencil to rub out and I only have a few slices left at present. 

I eagerly tallied up the number of tetrads that fall inside my 5MR, including those where only a tiny fraction falls within the zone. Such as these two, for instance

I see you, 36P and 37K. I shall be visiting you both this summer

I've actually been to the Camas Mor slip before. There was a lady doing tai chi in the car park, but she immediately stopped when she saw me turn up. I recorded Sea Slater and I think Porcellio scaber - that's all I can remember! I'll make more of a concerted effort next time I'm up that way. 

In total there are fifty two tetrads in my 5MR. Many of these only encroach to a small degree (or to a positively tiny degree in the case of 36P and 37K above) but that just adds to the silliness of visiting every last one of them. I work well with clearly defined boundaries, this daft venture is right up my street. 

However, there are three tetrads that I won't be including. And here they are

Bottom left corner - 35S, 35N and 35T

Although these do fall within my five mile radius, I will not be including them, not whilst we're in lockdown at least. Here's another image for you showing how far I need to detour to reach them. It takes me over twenty minutes to drive to Lyndale House (visible just below where I've scribbled '35S' in the pic above) and it's an eighteen mile drive to get there. I don't count that as a 'local' or an 'essential' journey, hence it just isn't happening. 

So I have 49 tetrads to visit this year. Shame I can't scrape up one more for a nice round number, but there you go. One final image for you, just to place 'me' in the whole plot. I'm the yellow dot in 36W, which just so happens to be the best tetrad on the whole Trotternish. Happy days, though I'll certainly be straying out of it plenty of times this coming season. 

Some interesting looking contour lines to the east of me. Reaching 46R could be a giggle...