geohashing

Geohashing expedition 2018-08-23 50 -1

This checkin to geohash 2018-08-23 50 -1 reflects a geohashing expedition. See more of Dan's hash logs.

Location

Hyden Wood, near Chidden. The woods look to be criss-crossed with footpaths, so this might be pretty achievable.

Participants

Dan Q

Plans

I’d originally planned on heading to 2018-08-23 51 -1 because I anticipated that it’d be on or near my route travelling South along almost the entire length of the 51 -1 graticule, but I didn’t bargain on such a Northerly hashpoint so I’ve changed plans and am now aiming to get to this one some time in the morning (I’m hoping to be in Winchester by lunch).

Expedition

The full story’s in vlog format, but here’s the summary:

Wasn’t originally planning to come to this graticule but instead was going to go to the 51 -1 graticule where I live ([2018-08-23 51 -1 see here]): I was going to be driving almost the entire length of 51 -1 on a journey from Oxford to Winchester anyway, so I figured it’d be easy to divert to any hashpoint. But when the Dow numbers came out, it turned out that the hashpoints in this quadrant of the Earth are all in the North-East corner, and so my journey would be in the opposite direction. Oh no! So instead I decided to “overshoot” and go for this graticule instead, and thus (if successful) expand my Minesweeper Achievement level.
Hashpoint deep in woodland in the beautiful South Downs National Park. Parked at The Sustainability Centre (and later made a donation via their website in thanks for the use of their car park despite not using their other facilities) and walked initially through woodland they manage and use for natural burials: this was really cool – I’ve always been a fan of body disposal in a low-environmental-impact, no-permanent-markers kind-of way, so I’m going to look more into what they offer. I was really interested to see that many families had left “named” bird nesting boxes in memory of their loved ones, which is awesome too.
Found geocache GC2X5BJ just outside the burial area and close to a point that gave me a great view across a valley towards the woods in which I believed I’d find the hashpoint.
Had to go some way off track to get to the hashpoint, but discovered a network of old, overgrown, long-abandoned (and not on any map I can find) trails in-between the thicket. In fact, the hashpoint eventually turned out to be on the edge of such a track, which I was able to follow to help me find my way back to a road.
Found a sign pointing to “Droxford”. Oxford is so-named because its location coincides with the most-downstream point on the Thames at which it’s possible to ford the river while driving cattle (i.e. “ox ford”) – incidentally, I’m told, the ford was at the point that Folly Bridge now stands. But what’s the etymology of Droxford, I wonder. What the hell is a drox???
On the way back, diverted by geocache GC5P5KN and found it: this was a great cache with the best-made variant of the particular kind of container it used that I’ve ever seen.

Update: A little research later, it seems that the “ox” in each of Oxford and Droxford have completely different etymological roots! Droxford is derived from an ancient name for the area from some time prior to the Middle Ages: Drocenesforda. “Drocen” means “dry”: the name means “dry ford”. The River Meon, which flows through the area, flows shallow over a chalky bed and is easily forded in many places, as these motorcyclists show. The things you learn!

Tracklog

Download full tracklog (includes boring bit where I drive down the A34, too…)

Video

My vlog of the expedition (also on QTube), for if you like to watch a sweaty man complain about there being too many trees in the woods

Photos

Dan in the woods — Heading into the forest.

Dan near the forest. — Heading into the forest… and trying to smile about it despite the imminent drizzle.

South Downs Natural Burial Site. — Well, that’s one way to dispose of a body.

View across the valley. — View across the valley to the woods on the other side.

Barbed wire fence. — No shortcuts here, though: going to have to go around!

Path to the woods with the hashpoint. — This path looks promising, though, and might get me somewhere near the hashpoint.

GPSr showing 0m distance to target. — Ground zero!

Dan with silly grin. — Traditional geohashpoint “silly grin”. Complete with dampness and leaves and debris stuck all over me.

Panorama of the hashpoint. It sort-of coincided with a long-abandoned (and not on the map!) trail.

Geocache in a fencepost. — Awesome geocache hiding place.

Geocache removed from a fencepost. — Lift off the top of the entire post and the container is inside. Genius.

My journey to the hashpoint began with about an hour and a half’s driving, but most of it I was going to do anyway.

Walking part of the journey to the hashpoint. — Annotated map showing the walking portion of the route.

Geohashing expedition 2018-08-22 52 -1

This checkin to geohash 2018-08-22 52 -1 reflects a geohashing expedition. See more of Dan's hash logs.

Location

Field with public footpath, East Adderbury.

Participants

Dan Q

Plans

I’m keen to get to level 2 of the Minesweeper Geohash achievement, and this far-South-of-graticule hashpoint represents an opportunity to achieve that. I’ll be at work during the day, but – energy levels permitting after what’ll have been a long day! – I’ll find a way to get up here and see if I can get to the hashpoint, aiming to arrive probably around 18:30.

Expedition

It had been a long day at work, but it looked to be a beautiful evening and I promised myself a pub dinner if I made it to the hashpoint, so I set out by car and by foot to East Adderbury, the village nearest to the hashpoint. The village itself is stunning: lots of old stone buildings, a very traditional bridge, and beautiful green spaces. I spotted not one but two candidate pubs (The Red Lion and The Coach & Horses) as I passed through the village, which was a reassuring start, and then pressed on down a lane which quickly became a narrow trail, waving to some cows along the way (why do I always seem to meet cattle on my hashing adventures?).

The trail was full of blackberries so I wasn’t short of a snack, but it soon became clear that it wouldn’t get me any closer than 35m to the hashpoint. I returned to the entrance to the cows’ field and, hopping a stile, crossed it. The cows looked puzzled as I paced around, getting to ground zero, but didn’t object. After shooting the traditional silly grin, I turned tail and headed back into the village and to the Coach & Horses, which proved to be the very essence of a British village pub: a husband and wife couple running it, dogs everywhere, a jar of pickled onions behind the bar, and more beers than you can shake a stick at.

I did enjoy a rather unusual conversation at the bar, though –

 Me: Can I get a ham, egg, and chips please. And a pint of bitter shandy.
 Barman: One egg or two?
 Me: Oh! Two, please.
 Barman: (Pause) We haven't got any eggs.
 Me: Uhh. Okay; no eggs then.
 Barman's wife: We've got one egg.
 Barman: We've got one egg.
 Me: I'll have one egg, then.
 
 (I go and sit outside; after a while, my meal arrives. There are two eggs.)
 
 Barman's wife: I found another egg.
 Me: ...

A fuller description of the entire adventure can found in the vlog I made along the way.

Tracklog

Download full GPX tracklog

Video

I filmed my adventure in a vloggy format, complete with doubling-back, talking to cows, and anecdotes about pub food. Watch it on YouTube or on QTube.

Photos

Achievements

Dan Q achieved level 2 of the Minesweeper Geohash achievement

by visiting coordinates in Swindon, United Kingdom and 2 of the surrounding graticules.

A footpath - this looks promising... — A footpath – this looks promising…

Dark clouds overhead. Hope the weather holds!

Pub with WiFi password visible. — Take a look at that WiFi password! (Also, good-looking pickled eggs!)

Dan drinking shandy. — Pint of shandy while I wait for my chips with no, I mean one, I mean two eggs.

Ham, egg, and chips. — A well-earned dinner at last. With eggs. Two of them.

2018-08-22 52 -1 Geohashing expedition to East Adderbury

Dan’s successful geohashing expedition to a field of cows near East Adderbury (and one more point on his Minesweeper grid!). More details.

Also available on YouTube and on QTube.

How Much of My Graticule is Covered With Water?

I’m a moderately-keen geohasher, as you might be aware if you follow my geohashing logs or you saw that video of me going ‘hashing earlier this month.

For those that don’t know, the skinny version is this: in May 2008 an XKCD comic was published proposing (or at least joking about) a new game with a name reminiscient of geocaching. To play the game, participants use a mathematical hashing function on the current date and the most recent Dow Jones Industrial Average opening value to generate sets of random coordinates around the globe and then try to find their way to them, hopefully experiencing adventures along the way. The nature of stock markets and hashing functions means that the coordinates for any given day are effectively random and impossible to predict (far) in advance, so it’s sometimes described as a spontaneous adventure generator.

XKCD comic #426, "Geohashing" — The XKCD comic that started it all.

Recently, I found myself wondering about how much of a disadvantage players are at if they live in very “wet” graticules. Residents of the Channel Islands graticule (49 -2), for example, are confined to two land masses surrounded entirely by water. And while it’s true that water hashpoints can be visited if you’re determined enough, it’s still got to be considered to be playing at a disadvantage compared to those of us lucky ones in landlocked graticules like mine (51 -1).

And because I’m me and so can’t comfortably leave a question unanswered, I wrote a program to try to answer it! It’s among the hackiest, dirtiest software solutions I’ve ever written, so if it works for you then it’s a flipping miracle. What it does is:

Determines which OpenStreetMap tiles (the image files served to your browser when you use OpenStreetMap) cover the graticule in question, and downloads them.
Extracts information about the colour of each pixel in each tile.
Counts the proportion of “water blue” pixels to other pixels (this isn’t perfect, because it trips over things like ferry lines on the map as being “not water”, especially at low zoom-levels).

Extreme zoom-in on Worcester College Lake, on OpenStreetMap. — Some parts of Worcester College Lake are identified as “not water” on account of the text overlay.

I mentioned it was hacky, right?

You can try it for yourself, if you’d like. You’ll need NodeJS, wget, wc, and ImageMagick – all pretty standard or easy-to-get things on a typical Linux box. Run with node geohash-pcwater.js 51 -1, where 51 -1 is the identifier for the graticule you’re interested in. And in case you’re interested – the Swindon graticule (where I live) is about 0.68% water, but the Channel Islands graticule is closer to 93.13% water. That’s no small disadvantage: sorry, Channel Islands geohashers!

Update 2018-08-22: discovered some prior art that takes a somewhat-similar approach.

Geohashing expedition 2018-08-07 51 -1

This checkin to geohash 2018-08-07 51 -1 reflects a geohashing expedition. See more of Dan's hash logs.

Dan cycling to a hashpoint. — Setting out by bike to the hashpoint.

Overgrown footpath. — This footpath is less overgrown than I feared it might turn out to be.

Dan in a field. — The first field I found myself in was – just about – navigable by a (pushed) bicycle.

Dan's bike by a narrow footbridge over a dyke. — But eventually my bike had to be left behind and I carried on alone.

Dan at geohashpoint 2018-08-07 51 -1. — Success! Silly grin engaged as I stand at the hashpoint.

First field on the geohash expedition. — The fields had recently been harvested of their corn.

Panorama around hashpoint 2018-08-07 51 -1. — It’s a whole lot of fields (panoramic photograph).

Surprise gasometer — On the way home, I spotted a gasometer and photographed/filmed it for my US friends (they’re even rarer in the US than here)!

Gasometer entry gate — For obvious reaosns, they don’t let idiots like me get up-close with enormous containers full of flammable gas, even when (like this one) they’re actually empty.

Screenshot from Geohashing app showing hashpoint reached — Success! Because I didn’t EXPECT to be hashing today, I didn’t have my GPSr and so didn’t make a tracklog, but my phone managed to get me there.

Location

A field South of Oxford

Participants

Dan Q

Plans

My meeting this afternoon got cancelled and my nearest hashpoint is only 6.5km (4 miles) away from my office. I can get this!

Expedition

After a productive morning’s work, I was genuinely slightly disappointed that a meeting I was scheduled to have this afternoon had to be rescheduled. But on the other hand… that meant that I could get away with extending my lunch break slightly and getting out to the hashpoint! I’d initially worried that it’d be inaccessibly buried on private land when Google Maps and satellite photography showed it to be deep in a block of cornfields, but OpenStreetMap came to the rescue and showed a public footpath somewhere in the very close vicinity of the target coordinates. And so, jumping aboard my bike, I set out!

600m from the coordinates I ran out of road and switched to the footpath, which I was pleased to discover was in reasonably-good condition: many underused local footpaths are not being very well-maintained at the moment and are often overgrown, but I was even able to bring my bike along this one and into the first field, although I had to push it rather than ride and I soon learned the error of my ways when the terrain got even rougher and I reached a narrow bridge – too narrow for my bike – spanning a dyke and entering the second field. Both fields had recently been cleared of corn, and whatever route the official footpath was supposed to take became rapidly unclear, but that’s probably for the best because I’m pretty sure I wasn’t on it by the time I reached the edge of the next field.

The hashpoint seemed to be along the fence somewhere so I followed it along – waving to some nearby cows – until my phone told me that I was under 3m from the spot. Hurrah! I snapped a panorama photo and started heading back, pausing a few times when I realised that I really, really couldn’t find where I’d left my bike. On the cycle home I passed a Gasometer which, because I’m told they’re super-rare in the USA, I thought I’d snap a picture of for those of you who ‘hash on the other side of the pond to oggle at.

Video

I actually remembered to shoot video of this expedition (well, all within a kilometre of the hashpoint and mostly within the last 350 metres!). It’s mostly just me rambling as I ramble, although there’s (brief) explanation of the Surprise Gasometer for those of you who live in countries where you don’t routinely see these interesting structures:

Photos

2018-08-07 51 -1 Geohashing Expedition

Read the full hashlog report and see photos.

Also available on YouTube and on QTube.