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Largest Activation Zone?


#1

A question for the cartographic detectives.

Which English summit has the largest Activation Zone?

My nomination is Detling Hill - SE-013. The nominal summit is at TQ804586 with a height of 200m, but, by the rules of the English Association, a valid activation can take place anywhere above the 175m contour line. Using the OS 1:50000 maps the contour lines are at 10m intervals, so, to be on the safe side, I have used the 180m contour as the limit of the Activation Zone. As far as I can see, the area above 180m stretches from Junction 3 on the M2 (TQ749622) to a point near the village of Dunn Street (TQ983482). I make that a distance of around 27.25 kilometres.

Have I missed a vital contour line somewhere? Can anybody nominate a summit with a larger Activation Zone?

73 de Les, G3VQO


#2

In reply to G3VQO:
Golly, Les, that’s so huge its almost pointless going to the summit!

Any nominations for the smallest AZ?

73

Brian G8ADD


#3

In reply to G8ADD:

Any nominations for the smallest AZ?

Probably one of those pointy sea stacks in the Scottish Isles I would guess…

73 Marc G0AZS


#4

I know Kinder Scout has a large AZ in terms of area, even if not over a length of 27km. There are plenty of large AZs I have visited, but where they rank amongst each other I others I don’t know - Ingleborough, Hail Storm Hill, Winter Hill, Cheriton Hill, Bishop Wilton Wold, Normanby Top etc.

Smallest AZ? It’s probably one I’ve not been to like Tryfan, but some of the smaller ones I have done will include Snowdon, Slemish, Great Gable and Dufton Pike. Probably the smallest in UK terms could be one of the St Kilda sea stacks.

Tom M1EYP


#5

In reply to G0AZS:
I was thinking more of the smallest in G, in GM the top of the Inaccessible Pinnacle is, how shall I put it? Petite?

73

Brian G8ADD


#6

Yes Brian, but the AZ there is bigger isn’t it? ie, the ground immediately below the IP is less than 25m vertically below it. IIRC anyway. I know your purist views on this one, but the question was about AZs.

Cheers, Tom M1EYP


#7

…that’s why I’m sticking to sea stacks with nothing but air and sea below you! :slight_smile: …and probably lots of Guano.

73 Marc G0AZS


#8

In reply to M1EYP:
Actually the In Pin and these sea stacks have got quite big areas in their AZs, the trouble is that the AZs are close to vertical - but you could operate from a hanging belay below the top! (Today’s pleasant thought!)

73

Brian G8ADD

PS yes, Tom, I am indeed a purist in this, Sgurr Dearg might be within the AZ but it isn’t the In Pin, treating Sgurr Dearg as within the AZ changes the hardest summit on the mainland to a fairly easy one - but imagine running a long wire from there to the top of the In Pin!


#9

In reply to G0AZS:

It makes for a soft landing!

I imagine that we will accept the climbing restrictions in the breeding season as applying to SOTA, too. Otherwise one might become too familiar with the bad habits of Fulmars!

73

Brian G8ADD


#10

In reply to G3VQO:

I make that a distance of around 27.25 kilometres.

:slight_smile: To get back to Les’ topic, I had a spare moment so I took a look at the SRTM data for the area around SE-013 using “Radio Mobile”… and actually I make the AZ 28.14 km from NW to SE.

For those that have Radio Mobile software, try it out. Make a map centred on your summit of interest then change “picture properties” to show “coloured slope (relative)” with “maximum elevation” set at 25m below the summit height. You will then have a nice coloured map with the AZ standing out in grey. Then you can measure it any which way you like.

If you want any more guidance, email me directly.

73 Marc G0AZS


#11

Hi Marc,

Interesting stuff.

I think that the area in km^2 would be a more interesting measure, and a more consistent way to compare and “rank” the summits. Can the Radio Mobile software calculate the area of the grey region?

Whether it’s the rank by area, or rank by length, I would like to see a top ten largest and top ten smallest AZs for each association. It would make a great feature to be submitted to Roy’s SOTA News each month. I don’t have this software… any volunteers?

Tom M1EYP
(at work, killing time between lessons and a parents’ evening tonight. Listening to VOA on MW0YLS’s old rig and having a listen around generally. A new ‘perk’ of the job! The radio course here is getting better every week and the pupils are brimming with enthusiasm - just ask G3CWI who was our “visiting speaker” last week. Thanks to all of you who have supported the project so far).


#12

In reply to M1EYP:

Can the Radio Mobile software calculate the area of the grey region?

Hmm not sure… I’ll have a look but it’s really for calculation of radio coverage. The map drawing is a bit of a bonus.

Incidentally, “The Cloud” shows an oval shaped AZ about 480m long (NW to SE) and 250m wide (NE to SW). Does that jive with what’s on the ground?

73 Marc G0AZS


#13

Yes, spot on.


#14

Hi All

So I have bitten the bullet and worked out how to answer Les’ question objectively. I will write up what mapping and image analysis tools are needed (some free, some definitely not) and the methodology when I do a “paper” or something with the results for a news item in the future.

But just to give you a feel for some of the data I can extract, here is the CE summits trial run showing the AZ in km^2 and the length of the perimeter of the AZ in km (if you wanted to walk it).

Summit-------Area-----Perimeter
G/CE-001------2.111------9.313
G/CE-002------0.255------2.579
G/CE-003------1.075------6.444
G/CE-004------0.169------1.638
G/CE-005------1.731------10.517

What else would you like to know for each summit?

Watch this space for the rest… although it will take me a while :slight_smile:

…and by the way, I can do this for pretty much any summit, in any association.

73 Marc G0AZS


#15

In reply to G0AZS:

That will certainly give some impressive statistics Marc. Thanks for taking the research to such a technical level. I’ll await the results with great interest.

73 de Les, G3VQO


#16

Great stuff Marc. Similarly looking forward to the results. With the scope for all the regions and associations, top ten/bottom ten ranks etc, this could become a monthly news feature. However, I understand that the calculation is “involved” the the process non-instant, so NP if it is to be just an occasional treat.

I think the 20 biggest/20 smallest AZs in the G association would be my data report of choice. Do you do requests?

Cheers, Tom M1EYP


#17

In reply to M1EYP:

Do you do requests?

Depends :slight_smile:

I was planning to try and get the G summits done (per the original request) and then see where it goes next.

The question for me is what data is interesting and how would you like to see it reported?

The obvious one is the area of the AZ… but is km^2 OK for everyone? (some will be quite small) Otherwise they could be stated in hectares (100th of a km^2) which might be more meaningful but less familiar to some… or do we revert to acres? :slight_smile:

Anyway, now is the time to ask before I get too far into it.

73 Marc G0AZS


#18

In reply to G0AZS:

This is very interesting, but I imagine most activators are more interested in the distance and height gain from the nearest access point!

73

Brian G8ADD


#19

Good question Marc, and my answer is informed both by my own walking activities, and the dayjob!

Because OS Explorer maps are divided into 1km by 1km squares, and because the conversions between metric units are taught widely and consolidated in schools (traditionalists fret thee not - imperial stuff is still taught as well, contrary to popular myth!), we have a ‘feel’ for km^2, and therefore km^2 is appropriate. The decimal system is easy to interpret, so I don’t think there’s any need to move the digits along a couple of places to report the areas in hectares.

Yes, the AZ area data for G summits would be most interesting (for me). Either in region lists, ranked (or both).

Tom M1EYP


#20

In reply to G8ADD:

I imagine most activators are more interested in the distance and height gain from the nearest access point!

Hi Brian

Well that’s outside the scope of my tools. I’m using topographical data to look purely at the area of summit within the vertical separation. i.e. The shape of the landscape and not the features on it. If someone wants to get their Memory Map or Anquet (etc) software out to look for access points in/near the AZ… I’d be curious too.

Anyway, this is a statistical exercise that may have no use other than to pass the lengthening evenings. :slight_smile:

73 Marc G0AZS