Black Hole in Catskill Escarpment

Chat about the Catskill Mountains in general.

Black Hole in Catskill Escarpment

New postby Jon » Wed May 16, 2012 1:33 pm

So I am a map person, and I have noticed something very odd that happens on the escarpment when looking at it on computer maps....there seems to be a vortex, or some gravity well that sucks everything into it. The elevations drop, the contour lines stack up, the pixels fuse together. Don't know what I'm talking about?

Open up my garmin mapsource, and from the birds eye view the topo takes a turn for the worse

The lake with the big purple section around it is North-South lake.
Image

So I zoom in on this cluster to see what's going on
Image

It looks like there is just a sudden drop in elevation down thousands of feet in what should be the edge of the escarpment. I've hiked there and don't know of any pit of death.

So I say OK maybe it's just my mapsource data is wrong or corrupted. let me check it out on Google.
SO I open up google maps, turn on the terrain settings and look for north-south lake.

What is that?????
Image

You're not allowed to zoom in very far with the terrain feature turned on. So I went to satellite view and zoomed in:
Image

So I said "no way!" The Google maps is only a 2d orthoimage. The Google Earth offers a 3 dimensional view. So I zoomed in on it in Google Earth

Here are two screenshots of it. If you can cross your eyes so the images overlap you can see the depth of the black hole. (or just download Google Earth and look at it yourself)

ImageImage

So I said OK this has gotta be a google screw up. Since I am in this handy dandy map class where we make maps I decided to see what the USGS has to say about things. I download the USGS 24,000 Digital Elevation Models (DEMs) from the CUGIR database for most of the catskills. I loaded up DEM (w46elu.dem) from the website into my GIS program and took a look at the escarpment.


Here it is (i threw in a layer from the national hydrology database for N/S lake for reference) It's color coded from lowest->highest blue->red

Image

So cause it's a digital elevation model I can look at any pixel which are 20m squares and get an elevation. Here are two pixels I looked at (where the arrow is pointing)

Image
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The "pixel value" if you can see that number is avg elevation of that 20m pixel. Those elevations are in meters. So it goes from 740meters (~2425 ft) down to 109meters (~357 ft.)

So there is something terribly wrong if the USGS even has it wrong. It's not just google....


If anyone has watched the twilight zone this is it. What happened to the Escarpment? Is there a tear in space and time? Is it 2012????? Is this a black hole sucking the planet through the Escarpment?
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Re: Black Hole in Catskill Escarpment

New postby mike » Wed May 16, 2012 10:48 pm

Oh...that's Bear's Den. One of the best views in the catskills.

Image
picture taken of North-South Lake from Bear's Den
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Re: Black Hole in Catskill Escarpment

New postby Jon » Thu May 17, 2012 9:02 am

is the Bear's Den 2000 feet deep? Is it like a cavern or a hole?
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Re: Black Hole in Catskill Escarpment

New postby mike » Thu May 17, 2012 2:10 pm

It is mainly a chunk of rocks. Some of them are conglomerate rock and some are solid rock. There are cracks in the rocks that do go down quite a ways. Maybe 30 feet? It is possible that there are deeper sections. But, I suspect that the topo above is wrong. It is a weird section of rocks. But, the views are great. Most people skip the side trail that leads to Bear's Den. NYS has the wrong name on the trail sign too.

I know that Rich K has explored this region more then I have. So, maybe he can comment further on it.

I too have seen the weird marking on the topo maps, and could never figure out why they did this. It was a popular destination in the Hotel Days. On the south end they used to have a wooden ladder. This was called Jacob's Ladder. This saved you from having to hike all the way around Bear's Den to get on top of it. There are some scrub pines near the rocks in the arial photo.
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Re: Black Hole in Catskill Escarpment

New postby mike » Thu May 17, 2012 3:38 pm

I checked the latest USGS topo, and they now just show a ridge with open spaces w/o trees.
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Re: Black Hole in Catskill Escarpment

New postby Jon » Fri May 18, 2012 9:26 am

What year is your quad Mike? I found a quadrangle that is in a data form that I can use in arcGIS from http://gis.ny.gov/gisdata/quads/drg24/index.htm. Here's a snip of the region. I'm not to sure which year it's from, one thing I have says 1980 and another says 1996. So it could be either. Anyone know where to get any more recent data? Or is this the most up-to-date?

My red circle annotation persists because it's above all layers.

Image

Here I make it transparent, and you can see exactly where the anomaly is located. Is this the bear's den location that you were looking at?

Image

So from looking at this quad there is no anomalous feature there. It just looks like a normal ridge. This must be an error in data from the digital age.
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Re: Black Hole in Catskill Escarpment

New postby mike » Fri May 18, 2012 12:59 pm

We get ours from USGS, and we have the latest. We even have the new digital ones that came out last year. I think that the latest one are more accurate. I was never quite sure why they showed this particular spot.
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Re: Black Hole in Catskill Escarpment

New postby kennykb » Sat May 19, 2012 7:15 pm

Uhm. There are a couple of pixels of bad data in the USGS Digital Elevation Model. For what it's worth, the version at Cornell (http://cugir.mannlib.cornell.edu/bucketinfo.jsp?id=2442) is still faulty. I haven't gone and checked directly at the USGS - the downloads are enormous.

And the USGS database is where everyone else gets their contour lines from. What, you thought they went out and surveyed them independently?

Your tax dollars at work.

(Really. The minuscule part of my tax dollars that have gone to fund the Geologic Survey have been money vey well spent. Even if there is the occasional glitch.)

The USGS has the raw data that went into the DEM available. I don't have time right now to track down which data set introduced the glitch. My guess is that it's bad data from one of the spaceborne radar mapping missions, possibly SRTM-2000.
I'm not lost. I know exactly where I am. I'm right here.
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Re: Black Hole in Catskill Escarpment

New postby mike » Sun May 20, 2012 7:54 pm

You are right about USGS. All maps are derived from them. One of the major problems with the Catskills is the steep and incredibly rugged terrain. When you get into difficult sections, USGS topo maps are a guess as to what they are like. Therefore those difficult regions are inaccurate. Sometimes highly inaccurate.

I have the 3 major versions of the Kaaterskill maps.

The first was done in 1892. It was not particularly accurate. There were major mistakes. they surveyed certain sections and guessed at what the other sections were like. Some of these inaccuracies caused land disputes that still cause problems today.

The second survey was done in 1943. This survey fixed some of the missed regions. But, the difficult areas are still a guess.

In 1978 they did aerial photography and made corrections to the 1943 map. They then made some minor corrections and this flowed into the 1997 map, which is the most current. In 2011 they made this map digital, but has no details like roads, waterways, or houses. Just contour lines.

I have never seen where Bear's Den was located on USGS maps. Not sure how this showed up on some maps.
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Re: Black Hole in Catskill Escarpment

New postby rkugel » Mon May 21, 2012 8:20 am

Hi Everyone,

I never noticed the "black hole" on any maps before, but that's pretty cool. I am almost certain the area in question is Bear's Den. I believe the trail off the Escarpment Trail incorrectly labels the area as Sunset Rock, but I think the "real" Sunset Rock was located a bit to the south.

As Mike noted, years ago (early 1900's), there was a step ladder (Jacob's Ladder) that allowed ascent to Sunset Rock.

Regardless of the nomenclature, the view is spectacular. I attached two photos I shot back in 2009. One was taken in the summer and the other in the autumn.

I must advise anyone visiting the area to use EXTREME caution. As Mike noted, there are numerous crevices, some of then very deep and very narrow. If you were to take a misstep and fall in, I'm not certain you could climb out without a rope or ladder. Some crevices are also very narrow, so you could end up with nasty lacerations as you slid down. Above all else, please watch where you step and enjoy the view!

Rich K.

2009-0606-SunsetRock-North-01-1.JPG



2009-1008-SunsetRock-08.JPG
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