Features of Our Walk

Our Saturday Chiltern walk, ably led by Nick, took us for about 11⅔ miles (18¼ Km) in an approximately north westerly direction from Amersham to Wendover. We stayed within a height range of 100 to 250 metres, making for a comfortable walk through the undulating Chiltern landscape. As the pictures show, walking and weather conditions were good.

Crocuses in Little Missenden told us that spring had surely sprung.

Now prepare ye for some plots and graphs. Not too overwhelming, but hopefully quite interesting! You will see here:

• How far were we from the Centre of London?
• Outline Map of Our Walk
• Height Profile of Our Walk
• Some Facts and Figures
• Less Quantifiable Considerations
• Timing & Speed
• Track File
• Postscript


• Please Read Me! Thankyou!

How far were we from the Centre of London?

Our start and end points were Amersham (AMR) and Wendover (WNR) stations respectively, which lie within a radius of 32 miles, very roughly West North West of the centre of London. 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.

The start and end points of our walk were
both within a 68 mile radius, and both very roughly east south east, of the centre of London.

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.

Cornix Hypothetica, our hypothetical crow,
isn't any old bird, as we should know.
Cornix Hypothetica, many miles you'll fly,
drawing our "straight lines", in the sky.

And here you can see the start and end points of our walk, namely
Amersham (AMR) and Wendover (WNR) stations, in the context of
(1) the South East of England, (2) the centre of London (Charing X) and (3) the M25.
Degrees Latitude and Longitude feature on the Y and X axes respectively.

Outline Map of Our Walk

Our walk was roughly in a north westerly direction, from Amersham (Station) to Wendover, through the pleasant undulating landscape that characterizes this part of the Chilterns. At about 11⅔ miles (18¼ Km) it was a relaxing Saturday walk with only a few short ascents. It was still not quite mid-March, but we reached Wendover "just before candlelight".

Outline Map of Our Walk.
Degrees Latitude and Longitude feature on the Y and X axes respectively.

We were west of the Greenwich meridian. The map grid scales translate to about 1.112 Km per 0.01° latitude and a mean of 0.689 Km per 0.01° longitude (WGS 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. If 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 54 metres per 0.01° longitude compared with our present Amersham to Wendover 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 0.24 %, 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.

Height Profile of Our Walk

We reached our highest point between The Lee and Wendover, near Concord House and shortly before our path met the Ridgeway. The lowest point of our walk was in Old Amersham. As you can see in the table in the "Facts and Figures" section below, the difference between maximum and minimum heights attained was 149 m, which ties in with figures for maximum ascent and descent.

Height Profile
Units on the Y and X axes are metres and kilometres respectively.

Some Facts and Figures

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 Ordnance Survey® sea level reference as explained on OS® "hiking" maps. There you are!

"Walk facts and figures"

Extra, Less Quantifiable, Considerations

On any walk there are considerations which are very real but 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.

• Weather: As the pictures show, we had good walking weather, sunny with a few clouds, but without a single spot of rain.


• Ground Conditions: There were no muddy challenges.


• Signposting: These paths were quite well marked, although the markings were mainly of the nature "here's a footpath" or "here's a bridleway". However, we had OS® maps to tell us where we were headed.

Timing and Speed

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!

• Timing: Our walk started at about 10:45 and finished at about 17:15 with a total stop time of 1½ hours for lunch in Little Missenden.


• Speed: When taken with a total distance of 11.35 miles, the timing yielded a speed of about 2.27 mph (2¼ mph if you prefer). This is a comfortable walking speed, which, as I'm sure you'll agree, is quite acceptable for walkers of a "CLOGgie" calibre.

Track File

If you are keen to see our walk 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 data are based on WGS84. Of course, for copyright reasons, I do not show the OS-based or Google-based maps here.

And Finally - a Matter of Practicality

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!