Brentwood Circular
WALK FEATURES
Thorndon Park: 16 January 2016


Outline Map Elevations Facts and Figures Gradients Less Quantifiable Timing Map Display Readme index banner


Features of Our Walk through Thorndon Park in Essex

This walk of about 10 miles (15¾ Km) was ably led by Ralph. The heights stayed within a band of 30 to 114 metres, and with a total ascent and descent of 181 metres and a few modest "ups" and "downs" we had plenty of interest and good exercise. Walking weather was favourable, with temperatures between 0 and 5 degrees Centigrade, and sunshine for most of the day. It was possible to complete comfortably the walk within the daylight constraints at this time of year, since we kept the times for our lunch break and other stops within bounds.




On the southern end of our walk we had good views across South Essex as far as the Thames Estuary and beyond. Here we are at the Visitor Centre (South). I was photographing against the strong sun, hence the silhouette-like appearance of this picture.

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


Outline Map of Our Walk

Our walk was "circular" or more strictly "multiple figure-of-eight". The contortions in our route were intended by Ralph to provide novelty and to try to avoid too much muddiness. In this respect Ralph's efforts met with success. The map grid scales translate to 1.112 Km per 0.01° latitude and a mean of 0.691 Km per 0.01° longitude, all when using 6371.0 Km as the volumetric mean radius of the earth - as per the WGS84 standard!


Outline Map of Walk

I plotted our walk by hand on my return home. Of course, I tried to be reasonably accurate. Even OS maps, on which I based my plot, may not show all the required detail, but appear to give the requisite degree of accuracy in this case.

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 0.10 %, 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

It's of course fine to say that we reached about 114 m above sea level and descended to 30 m above sea level, but what's the significance of that? Probably, of greater interest when it comes to considering personal achievements, is the total ascent - which usually requires greater effort than the descent. On today's walk, the total ascent was 181 m, which as expected, was greater than the difference of 84 metres between maximum and minimum heights above mean sea level.


Height Profile

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!


Some Facts and Figures

Here are some "vital statistics" in metric and imperial units. The total length of the walk is measured on a conceptual "flat" plane at mean sea level, WGS84 style. Of course, as mentioned above, the total ascent exceeds the difference between maximum and minimum elevations; I'd suspect things, if the reverse transpired!


"Walk facts and figures"

Average Rising and Falling Gradients

And here, for the numerical fun of it, are the average gradients we overcame on our walk. The rising and falling (negative) gradients are both averaged over the distance given, with level stretches having rises and falls of less than ± ½ metre.


Rising and Falling Gradients

By comparison, Hertfordshire County Council recommends that its roads should not have longitudinal gradients of more than 5% and one of the steepest adhesion railways in the world, in Austria, has a maximum gradient of 11.6%. By way of further interest, the clockwise route of the Fairfield Horseshoe in the Lake District has a total distance of 15.62 Km (9.71 miles), with the following calculations: an average rising gradient of 14.66% over 6.589 Km, a level part over 0.345 Km, and an average falling gradient of 11.11% over 8.676 Km. This is seen by many as really quite challenging - but then, when you compare it with our walk, it can be said that we had a more leisurely and less demanding aim compared with Lakeland challenges!


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.


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.


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 the following file to do so. As mentioned above, the numerical data in this file have been hand-plotted by me (no GPS!) on my return home. The data are based on WGS84. Of course, for copyright reasons, I do not show the OS-based or Google-based maps here.


Postscript

Any map is an approximate representation of what is, and my plotting thereon certainly 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!