Colin Pearson Memorial Walk
Saturday 11th November 2017
|WHERE ? MAP HEIGHTS FIGURES TIMING TRACK EXTRA FINAL READ ME|
On our gentle 8½ mile walk from Cockfosters Station to Turkey Street Station in North London we reached the dizzy height of about 100 metres (328 feet) above sea level. It was a walk characterized by the gentle scenery around the northern rim of the Capital, scenery bathed in the rich colours of autumn. Indeed, despite the clouds and some early rain, we actually had reasonable walking weather. A most enjoyable way to commemorate Colin.
Now prepare ye for some plots and graphs. Not too overwhelming, but hopefully quite interesting! You will see here:
Our start and end points were the stations at Cockfosters and Turkey Street respectively. They lie within a 12 mile radius of the centre of London, and very roughly, to the north thereof. The centre of London is officially taken as the intersection of The Strand, Whitehall and Cockspur Street. This intersection is often referred to as Charing Cross, not to be confused with the nearby Victorian Eleanor Cross itself, nor the station in front of which the cross stands. The detailed figures, for the fun of it, are as shown below.
Our "straight line" distances are actually "great circle" distances on the earth's surface. We assume the earth to be spherical, which is not far off the mark. Assuming the earth to be a sphere gives us an error of about 0.1% in our distance values. Not that much really! Can't complain! Indeed, we can speak of the distances as the "hypothetical crow" (cornix hypothetica) flies.
Our "linear" walk from Cockfosters to Turkey Street along part of the London Loop took in some of the gently undulating scenery around the northern rim of the Capital. We accomplished "our mission" well within the available mid-autumn daylight. A nice relaxing walk with only a modest total ascent.
We were west of the Greenwich meridian, hence the negative longitude values. The map grid scales translate to 1.112 Km per 0.01° latitude and a mean of 0.690 Km per 0.01° longitude (using the WGS84 standard), both when using 6371.0 Km as the volumetric mean radius of the earth. It is interesting to compare the present longitude distance-to-degree ratio with that for other walks. It you do this, you will see that the further north you go, the less Km per degree longitude you get. Once you get to the Lake District the reduction in this ratio compared to that for walks in the south-east is quite noticeable. In Scales, in the Lake District, we already have a slightly smaller value of 0.644 Km per 0.01° longitude - a difference of 50 metres per 0.01° longitude compared with our present North Kent walk.
Because we don't live on a flat earth - unless you are a convinced "flat-earther" - maps are inevitably a distortion of what is. In other words, it's all a matter of mapping a curvaceous surface onto a flat surface. We don't want to carry curvaceous representations of the terrain on our walks, do we? In our case, the northern length of our map grid is stretched out by something like an extra 0.07 %, to make it the same on the page as the length of the southern part of our map grid. Not that much for hiking purposes really! Can't complain.
Our highest point of 100 metres (328 feet) above mean sea level was actually Cockfosters Station, and our lowest point was at 24 metres (79 feet) shortly before our end point at Turkey Street Station (25 metres, 82 feet). Overall, our walk gradually dropped towards the Lea Valley, but the "ups and downs" in between helped to give our walk some scenic interest. These "ups and downs" also help to explain why the total ascent and descent are invariably greater than the maximum and minimum heights on a walk. Indeed, it's the total ascent which gets closer to being a measure of our fitness, rather than the maximum height reached.
The above plot uses a true origin for the vertical elevation (height) axis, so as not to lose track of reality. What a worthy aim!
Here are some "vital statistics" in metric and imperial units. The total length our walk is measured on the surface of the WSG84 spheroid. However, we can consider this, without undue loss of accuracy, as being on a conceptual "flat" plane at mean sea level, using the OS sea level reference as explained on OS "hiking" maps. There you are!
On any walk there are considerations which are very real but are often tantalizingly out of ready reach of those who wish to espouse a numerical approach to many of life's activities. Here are three considerations for starters.
It's one thing to discuss the terrain over which we walk. It's quite another to ask how we personally respond to walking over that terrain. There are a number of considerations, of which timing and speed can be taken as starting points, should you wish to wax enthusiastic in these areas!
If you are keen to see our walks superimposed on an Ordnance Survey® (OS) map or on another system such as Google Maps®, then you can use this file to do so. The numerical data in this file were derived from my GPS. The data are based on WGS84. Of course, for copyright reasons, I do not show the OS-based or Google-based maps here.
Any map is an approximate representation of what is. Practicality and scale are relevant considerations. We are not dealing with a planning application calling for detailed spatial descriptions of intricate boundaries. For us in the hiking community, the degrees of accuracy and precision should be just enough to give us useable and helpful knowledge of the terrain about us and beneath our feet. I hope my humble endeavours on this page are in this respect interesting for, and useful to, you my reader!