Exactly where are the Geryons?

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Exactly where are the Geryons?

Postby guyburns » Mon 13 Apr, 2020 6:54 pm

I'm going through the negatives of Chris Binks and am working out where certain photos were taken on his trips to South Geryon and The Foresight. Chris was in the parties that first ascended those two peaks in November 1950 and Jan 1951.

I would like the precise co-ordinates of North Geryon, South Geryon, and The Foresight, so that when I try and mimic photos in Google Earth, I can work out from where they were taken. The problem is: exactly where are these peaks? Here's the classic view of the three, looking over the Labyrinth from Walled Mt, with a GE mimic below it (GE has problems in this area; see below).

Ques 1
Are the lakes I've named correct?
BC023.jpg

BC023 GE Mimic.jpg

Here's my problem:

Placenames Tasmania only knows Mt Geryon, it is not subdivided.

• Google Earth is not capable of showing the classic view of Geryon showing the three separate peaks.

• The 1:25000 Tasmap, Du Cane, does not show the three peaks. Below is a 100% crop from that map:
Tas Map.jpg

Ques 2
On the Tasmap, what are the co-ordinates of the three Geryons?

Google Earth Elevation errors
It appears that GE has elevation errors that do not allow it to show the Geryon/Acropolis summits, even approximately. I've finally realised that's why I couldn't locate the three Geryons in GE. Here's a kmz file (https://www.mediafire.com/file/xyqf7i3n ... n.kmz/file) that takes you to what I think is Spot Height 1507 on the Tasmap (just above "Mt Geryon")

Ques 3
What are the GE co-ordinates (lat, long, decimal minutes please) of the three Geryons? Once I have these, I can accurately put a name to where Chris's photos were taken from.
Note that the "dashed" area west of Mt Geryon between two creeks (a boulder field) is also visible in the 1950 photo from Walled Mt and the GE mimic.
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Re: Exactly where are the Geryons?

Postby north-north-west » Mon 13 Apr, 2020 7:04 pm

According to MJD's spreadsheet (which is pretty accurate for those peaks he has climbed)

Geryon North:
421625E 5357795N
Lat 41.927926 Long 146.054714

Geryon South:
421630E 5357630N
Lat 41.929403 Long 146.054753

The Foresight is not mentioned.
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Re: Exactly where are the Geryons?

Postby eggs » Mon 13 Apr, 2020 7:12 pm

Your photo has labelled Lake Persephone as Pool of Memories.
Pool of Memories is a smaller tarn above and to the left of Persephone.

Lake Selene will be out of view - that one is Lake Hermes
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Re: Exactly where are the Geryons?

Postby tastrax » Mon 13 Apr, 2020 9:48 pm

Listmap is your friend for these types of investigations - add contours layer to make things a bit clearer. You can also change the grid reference to Lat Long etc in the bottom left corner

https://maps.thelist.tas.gov.au/listmap ... kId=476424
Cheers - Phil

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Re: Exactly where are the Geryons?

Postby eggs » Mon 13 Apr, 2020 10:55 pm

tastrax - I had not seen that display type in the List before - but the underlying data is still inadequate.
Not only does the topographic layer mistakenly label the southern block of the Ducane high area as Mt Geryon [Note the TASMAP basemap layer does label it correctly],
the 2 areas of Mt Geryon North [1520 contour] and Mt Geryon South [1510 contour] in both basemaps have no small contour lines between them to show the Foresight. It is completely absent!!
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Re: Exactly where are the Geryons?

Postby Azza » Mon 13 Apr, 2020 11:21 pm

The label is attached to the wrong points, but North and South Peak are pretty clear.
Here are the two GPS coordinates.
There is only a bit more than 100m between them. I would have thought they were too close to do any useful triangulation from a distance?
With the way they generate the contours is not a great surprise that level of detail has issues.
Screen Shot 2020-04-13 at 11.08.29 pm.png
Screen Shot 2020-04-13 at 11.08.29 pm.png (245.79 KiB) Viewed 2946 times
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Re: Exactly where are the Geryons?

Postby tastrax » Tue 14 Apr, 2020 9:07 am

Unfortunately there is no good LIDAR data to get any better contours in that area so yes, the Foresight is missing altogether
Cheers - Phil

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Re: Exactly where are the Geryons?

Postby Mark F » Tue 14 Apr, 2020 9:16 am

One could say they didn't show much foresight when they mapped the area. :roll:
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