Features of Our Walks from Porthmadog

The walks you see described here both started and ended at our residence, Snowdon Lodge. We did not need any transport to get to the start of these walks, or indeed, to link separate parts of the same walk. "Portmeirion" and "Slate" were the main themes of our excursions. Total ascent for each walk was of the order of ½ Km. We had lots of sunshine with barely any rain. Nice!

On the second day, our walk took us to Llyn Cwmystradllyn. In the distance we could see the Gorseddau Slate Quarry, which already early on proved not to be a financial success.

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

• Where is Porthmadog?
• An Outline Map of Our Walks
• Height Profiles of Our Walks
• Some Facts and Figures
• Weather, Ground Conditions & Signposting
• Timing & Speed
• Track Files
• And Finally

Where is Porthmadog?

Porthmadog is just outside the Snowdonia National Park. The town lies south of Snowdon, Carnarfon and the A5 from London to Holyhead. While Porthmadog's harbour never really achieved the status of Holyhead as a departure point for Ireland, Porthmadog is very much a focus for walking and sightseeing as we found.

Here you see a "sketch" of the U.K. showing the approximate locations of Porthmadog and London.
This "map" is from the Microsoft® PowerPoint® Clip Art Library originally supplied with versions of MS Office®.

If you espouse the quantitative in life, we have some numbers for you! What are these "great circle distances"? If you haven't met these before, I'll try, in my humble way, to give a little bit of an explanation. A great circle is the largest circle that can be drawn on the surface of a given sphere. As a consequence, its centre coincides with the centre of the sphere. We assume the earth to be spherical. It makes our maths "reasonably" easy and gives us a maximum error of about 0.1% in our distance values. Not that much really! Can't complain!

If you espouse the quantitative in life, here you duly see some numbers!

Our "straight line" distances are actually "great circle" distances on the earth's surface. 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 for us you go,
with many a "straight line" o'er Earth to show.

Outline Map of Our "Circular" Walks from Porthmadog

There were at least two walks on Saturday and two on Sunday. The two I describe were the two I led. The Portmeirion walk on Saturday, 4th May is coloured dark red in the map below, while the "quasi circular" walk to the Slate Mill and Llyn Cwmystradllyn on Sunday, 5th May is coloured green. For clarity, the same colours are used for the height profiles and the summary figures you'll find further below. "Golden arrows" in the map indicate the direction of a walk. Where the two paths overlap spatially on the map, the colour of the later walk takes priority - because of the way my spreadsheet works!

Outline Map of Our Walks
Y and X axes are in degrees latitude and longitude respectively.

"minus" indicates degrees longitude west of Greenwich.

The map grid scales translate to 1.112 Km per 0.01° latitude and a mean of 0.670 Km per 0.01° longitude, all when using 6371.0 Km as the volumetric mean radius of the earth - as per the WGS84 standard! In Scales, in the Lake District, the longitude scale is less (as expected), with a mean of 0.644 Km per 0.01° longitude; in fact, in doesn't take too much brain power to conclude that in Scales the distance is 26 metres per 0.01° longitude less than in Porthmadog!

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 an extra 0.21 %, 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 Profiles of Our Walks

It's of course fine to say that we reached about 620 feet 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 the two walks described shown here, the total ascent varied from one walk to the next in a range of between 1 Km down to about ⅔ Km. The starting elevations were about 7 m on both days. There is a slight discrepancy in the start elevations between the two days; in this case, I felt that looking for the last metre was not going to be that useful or appreciated! The total ascent was, as expected, was greater than the difference of between maximum and minimum heights above mean sea level as defined by the OS® reference at Newlyn in Cornwall.

Height Profile
X and Y axes are in units of metres and kilometres respectively.

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"

Each route was derived using my GPS (Garmin®). Hence, the distances for each walk will include some walking at about at places of interest; therefore, for each walk, these distances may be about ½ to 1 Km above "true". However, all the results shown on this page are for indicative purposes and do not aspire to the heights of scientific accuracy, however precise the results may be!

Weather, Ground Conditions & Signposting

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: It stayed dry, or almost so, on Saturday and Sunday. The day-time temperatures encouraged walking. The table below is derived from the "Accuweather" web site.
  
  "Weather"
  
  
  
• Ground Conditions: There was hardly any mud.


• Signposting: Unfortunately, many paths, while on the map, could not be found in practice. There were not many path markers.

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. If you wanted to, you could, for each walk, ascertain start and end times and times spent not walking (e.g. for lunch). Knowing the total distance covered in the walk and time spent actually walking, you obviously can determine the speed, which typically is about 2½ mph for a walk on flat terrain, reducing to (e.g.) 1½ mph on a more challenging terrain. I probably would not find too many takers for this information were I to calculate it accurately and precisely for each of the walks described here!

Track Files

If you are keen to see our walk superimposed on an Ordnance Survey® (OS) map, then you can use the following files to do so. The data in these files were recorded by my GPS (Garmin®). The data are based on WGS84. Of course, for copyright reasons, I do not show the OS-based maps here. Furthermore, the plot may also include some walkabouts in hostelries and sightseeing places; hence there may be a slight over estimation of the length of a walk by anything up to 1 Km.

Here are the Porthmadog walks: Portmeirion and Slate Mill,

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!