True height of Mt Geryon?

[Messidor]

Something that's bugged me for a while is the mismatch in height of Mt Geryon (North) between Tasmap and the Abels. The Abels give 1516m, but the map gives 1520-1530m, which, if true, would make it uncertain as to whether Geryon North or Du Cane Range nearby is the Abel. Either is pretty plausible in my opinion. So, which is higher? Are there any definite answers?

The attached image is my understanding of the features.

Attachments

[GPSGuided]

Sorry, not answering your question. But just want to say that they still have arguments and uncertainty over the height of Mt Everest using different surveying techniques and from different time points. So what's a difference of a few meters on different maps?

[Genesis]

Remember it's not the size that matters but whether you have bagged it or not

[waif]

Is Geryon even an Able? If you go off the Du Cane high point to the north and there isn't a sufficient drop between them

I'm not actually sure where the true peak of Geryon is due to the multiple pinnacles (I'd say Geryon North would be what we perceive as the summit -as per your annotations, with a elevation somewhere between 1520-1530m)

[Strider]

Is Geryon even an Able? If you go off the Du Cane high point to the north and there isn't a sufficient drop between them

Geryon is not an Abel. Du Cane Range is.

http://theabelmountains.com.au/abel-tab ... -st-clair/

[eggs]

From Wiki:

An unnamed peak on the main ridge of the Du Cane Range has an elevation of 1,520 metres (4,990 ft) above sea level[citation needed] and is the eleventh highest mountain peak in Tasmania.

With two peaks, Mount Geryon North has an elevation of 1,516 metres (4,974 feet) above sea level[2] and is the twelfth-highest mountain in Tasmania. Mount Geryon South, with an elevation of 1,509 metres (4,951 ft) above sea level,[3] is the state's fifteenth-highest peak.

These are also the heights shown at https://www.mountain-forecast.com/peaks/Du-Cane-Range

It is very subjective - but my perception was that we were slightly higher on the Ducane Range top.
But it seems fairly clear that the north peak is higher than the south.

[Azza]

I think the way it works out is that there isn't the required 150m drop between the DuCane high point and Geryon North and South? I don't think the drop to the foresight is much more than 50m, a big abseil?
However the DuCane Range as a whole qualifies to be an Abel, therefore it's taken to be the highest point on the entire range.

The Abel definition starts to seem a bit silly when awesome mountains like Geryon don't qualify.

Geryon North is a smidgen higher than South.

[Messidor]

It is very subjective - but my perception was that we were slightly higher on the Ducane Range top.
But it seems fairly clear that the north peak is higher than the south.

Hm, yes, I generally find that when I'm looking at another mountain with a similar height I find it often looks higher than it really is, so if it does look a little lower, then that is something to consider. Great photo by the way.

Sorry, not answering your question. But just want to say that they still have arguments and uncertainty over the height of Mt Everest using different surveying techniques and from different time points. So what's a difference of a few meters on different maps?

I guess it makes a difference to me because I'm a little particular about that. I often prioritise mountains with a greater drop (topographic prominence), so if Geryon was higher then that would be my biggest priority and Du Cane Range would be secondary, rather than vice versa. Geryon is spectacular mountain though, so it's a worthy objective regardless. I'd say it's different to Everest, because nobody is doubting which is the tallest mountain, right? (well, not if you're measuring from sea level)

The real reason I've posed the question is I'm on a quest to climb Tasmania's 50 "most prominent" mountains - those with the most drop. This might seem a little bizarre to some, but you'll find there's quite a lot like me out there, around the world. If Geryon is higher, then it will make the list, but currently Du Cane Range has its spot (50m vs. 580m drop/prominence!). You can check out the list on the link below:

http://www.peakbagger.com/list.aspx?lid ... &cid=12524

You can see the ones I've climbed. I haven't actually started proper, and I'm Victorian-based, so I've only done some relatively easy ones.

[DaveNoble]

What should not be in dispute is that the Geryon is the second best mountain to climb in Tasmania (and therefore Australia).

[eggs]

If you are after prominence as in "big drop", then Geryon beats Du Cane Range hands down.
In reality - they are part of the same block - but exposure is non existant on the Ducane top, but everywhere dramatic on Geryon.
[disclaimer - we looked at it, but due to time constraints did not climb it at the time]

I probably misunderstand "prominence", but Legges Tor is a rise on a vast plateau.
But I suspect you are simply after the high point of a mountain block/range that falls away on every side.
I presume there is a limit to how large the block/range can be, otherwise the high point of the central plateau might have got on the list?

[Messidor]

If you are after prominence as in "big drop", then Geryon beats Du Cane Range hands down.
In reality - they are part of the same block - but exposure is non existant on the Ducane top, but everywhere dramatic on Geryon.
[disclaimer - we looked at it, but due to time constraints did not climb it at the time]

I probably misunderstand "prominence", but Legges Tor is a rise on a vast plateau.
But I suspect you are simply after the high point of a mountain block/range that falls away on every side.
I presume there is a limit to how large the block/range can be, otherwise the high point of the central plateau might have got on the list?

What I mean by "prominence" is the same as the idea of "drop" that the Abels uses; it's purely mathematical. Essentially it is the least amount you can descend before you must reascend to a higher peak. To calculate it, follow the highest ridge to a higher mountain and find the lowest point on this ridge. Then subtract that height from the mountain in question's height.

This image should help:

From this calculation, we know that Pelion East is well over the 150m Abel threshold. 335m is quite prominent. As you can see from the list I attached, the top 50 most prominent almost all have over 600m prominence.

Legges Tor is second on the list because A. it's very tall, and B. it is separated from Mount Ossa (it's "parent peak") by very low ground. The fact that its a squat hill on a big plateau has no bearing on the value.

Ossa is no. 1 because it's the highest point on an island. There are no higher mountains - just sea in all directions. Its prominence is 1617m. The same goes for Mount Maria. It isn't very tall but it's on an island, so it's prominence = height.

Because Geryon is probably lower than the Du Cane Range, and the saddle/col between the two is not that deep, it has a very low prominence. Anyway, that's just the kind of stupid thing I obsess about. "50 Finest" is a bit misleading I guess. It really doesn't have anything to do with subjective quality.

[tastrekker]

More Geryon height discussion here:
http://bushwalk.com/forum/viewtopic.php?f=28&t=1105&p=16240&hilit=Gps+height+geryon#p16242