Tuesday 21 February 2012

Height of Everest

I sometime wonder if geodesists will ever agree on anything?  As long as I can geodetically remember there has always been a question mark over the height of Everest.

China and Nepal allegedly differ by 4m on the height (8844m compared to 8848m) and a new survey is meant to end it.  Mind you in 2004 the Chinese said it was 8848.5m having reduced from 8849.8m.  However this was to the ice and the 8844m is to the bedrock.  To be precise, they measure it was 8844.43m plus a 3.55m ice cap.  Helpfully the US National Geographic say it's 8850m.

If we assume we're pretty much agreed now on where the top is, it's where the bottom is which is now causing the issue.  The latest remeasuring is redefining the geoid but I've a feeling this won't be the end of it. 

Well, if the world stayed still for a moment it'd help but due to shifting tectonic plates, Everest grows by 4mm every year.

And does it really matter?

Sunday 19 February 2012

New York in 1000 Pieces

This is the last of my Christmas treats. It's taken me quite a while as it's 1000 pieces (I'm more of a 750 woman) and for some unknown reason I considered it cheating to use the picture. So I have stubbornly refused to peep at the finished image and consequently have taken what seems forever to complete it. We are staying in NY for a week in the summer. Roger now thinks I'll be able to navigate around without a street map.
12 02 19 New York puzzle
Hmmm, what shall I geo do now?

A Rare First Find

I am a bench mark missionary. A non surveying friend happened to stumble across this one today and was so elated (I think I'm over doing it here) he sent me the photo. It's his first BM find and he's managed to find a rare one.
12 02 19 BM at Fareham
We have a BM cut mark bolt on Exeter Cathedral but I didn't realise until today that they are not terribly common. Indeed, some geeky BM sites list cut marks with bolts as "highly prized by benchmark hunters". And to prove a point Jochta's bench mark website makes me look like a Mickey Mouse amateur at this game. In my bench mark googles this afternoon (I really should get a life) I came across Benchmarks.org.uk - what a find. It lists all the levelling routes taken. Bizarely I couldn't find this Fareham BM on it but perhaps I was just getting a bit bamboozled by it all by this stage.

Someone once told me that BMs with bolts mean that they are related to more than one datum but I can't find a source for this info. Anyone know?

Friday 17 February 2012

Lubeck Revenge

Visited Exeter Museum today.  It's recently reopened after a multi million pound refit.  I was not swept off my feet by any stretch of the imagination; same old exhibits in glass cases but at least they had made a few nice architectural improvements.

The (only) highlight was a map; the only one I found.  But at least it was interesting.  It's a late 1930s German map of Exeter with highlighted targets for the Lutfwaffe.  Targets include cultural buildings, war stores, hospitals and railway hubs.

12 02 17 Exeter Museum - Luftwaffe Map of Exeter
12 02 17 Exeter Museum - Luftwaffe Map Key
Exeter was bombed in 1942 as a revenge for the Allies' bombing of Lubeck.  There's no right in war is there?

Friday 3 February 2012

Woman in White

On return from a course in Fareham my colleague kindly agreed to humour me with a couple of trig bags on the way home. After all, what's life if you can't teach a naval aviator the joy of concrete lumps on hills?

The first one we bagged was Fort Kilkicker.  Stunning views across the Solent in the sun - a perfect day for trig hunting.  What Andy hadn't quite realised, in agreeing to this, was that not only was he my chauffeur but also my photographer. It didn't take him long to get in the swing of it.

12 02 03 TP3234 - Fort Gilkicker Trig
12 02 03 TP3234 - Fort Gilkicker BM
Nice plug.
12 02 03 TP3234 - Fort Gilkicker
And a very impractically coloured coat for trig hunting.
12 02 03 TP3234 - Fort Gilkicker
The second one was just an easy find; which was just as well in light of my previous apparel comments.
12 02 03 TP3705 - Heath Lane
Andy was starting to act like a pro lining up the trig, BM and plug for phots.
12 02 03 TP3705 - Heath Lane
12 02 03 TP3705 - Heath Lane
I suspect, however, that he'll be back to helicopter spotting rather than trig bagging before you know it.

Wednesday 1 February 2012

Is the Light Going Out?

Promoted by a lecture on GPS this week I thought I'd catch up on the latest regarding LightSquared and GPS. I am pleased to report that the apparent steam rollering through US legislation for approval for this has been halted by the US Government. The GPS community is at last being listened to - read all about it at Save Our GPS.

During my googling I came across the Wiki article on LightSquared. This is the first time I've come across a disputed article. All the gory details are on the 'talk' tab - it's certainly not a well balanced article as it stands.

Part of me feels sorry for LightSquared. They were obviously given the impression, somewhere along the line, that they would be given approval for this. Am I too soft?