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Wolf Creek dted data dive

post #1 of 12
Thread Starter 

It turns out that the 1 arc second SRTM topographic data for Wolf Creek is available. (SRTM is the Shuttle Radar Topographic Mission, which collected ground height data for most of the world during a mission from Feb 11-21, 2000).  1 arc sec works out to 101 feet North-South by 81 feet East-West.

 

This data lets us do fun things like this:

But a contour map is more useful: 

Of course, the question everyone is really dying to argue about, is "how steep is it?"

So here we go.  These are average sloples computed from the height data:

I fiddled the color map to put a sharp boundary at 35 degrees - anything red to orange to green is more than that:

Light blue to white to purple is going to be steep enough to have fun.  Dark blue? Better keep your speed up!

 

Here are zooms on the waterfall area, Alberta Peak, and the Knife Ridge:

 

 

Can you poke holes in this data?  Sure.  It was C and X band, and I don't know if that penetrates snow.  Apparently "thick vegetation" can cause returns from the canopy instead of the ground -- do big evergreen trees count?  Don't know.  Averages should still be not-too-far off, and Alberta Peak is above tree line.

 

Poke away!

post #2 of 12
I'm not what you would call a tech nerd, but that is very cool!

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post #3 of 12
Thread Starter 
Glad you like it!
It looks like everywhere in continental US is available. (I was doing the ritual incantation wrong the first time I looked for Jhmr data, but now I have it. )
post #4 of 12
This is something you pull up in Google Earth or specialized GIS programs?
post #5 of 12
Thread Starter 
The data is from the USGS earth explorer website. The processing and graphics is done with Matlab and scripts I wrote.

Now I'm wondering if I can do it on my phone, where I have Octave, an open source Matlab clone.

I can share the script if anyone cares enough for me to collect all the pieces.
post #6 of 12

Did you manually add in the lifts? I assume so as Nova is not on there.

 

I would be interested in adding some of this to the unofficial guide if permissible. Is the data source public domain?

post #7 of 12
Thread Starter 
Yeah, I read the lift locations off of Google maps. I have no problem with you using the pictures, but I guess I should go back and re-read the terms on the USGS site.
I think I can't redistribute the raw data files but processed should be ok. Anyone (well probably US residents) can get data if they register.

Pretty amazing, really. Not that long ago data at this resolution was classified secret.

I will double check when I have a chance and get back to you.
post #8 of 12
Quote:
Originally Posted by mdf View Post

Yeah, I read the lift locations off of Google maps. I have no problem with you using the pictures, but I guess I should go back and re-read the terms on the USGS site.
I think I can't redistribute the raw data files but processed should be ok. Anyone (well probably US residents) can get data if they register.

Pretty amazing, really. Not that long ago data at this resolution was classified secret.

I will double check when I have a chance and get back to you.

 

I'll check it out too. I think your script does a great job of conveying A) that there is steep terrain here and B) that there is really no way to ski it without flats.

post #9 of 12

Pretty cool images.  I'm a big fan of the free website caltopo (link below) which uses USGS survey data which I think has a little higher resolution.  Using similar color schemes as the above image creates:

 

 

 

 

http://caltopo.com/map.html#ll=37.46351,-106.78403&z=15&b=t&a=sc_s35-60cFF0000-00FF00,sc_s1-34c0000FF-FFFFFF&cl={%22cfglayers%22%3A[{%22name%22%3A%22%22%2C%22alias%22%3A%22sc_s35-60cFF0000-00FF00%22%2C%22id%22%3A0}%2C{%22name%22%3A%22%22%2C%22alias%22%3A%22sc_s1-34c0000FF-FFFFFF%22%2C%22id%22%3A1}]}

post #10 of 12
Thread Starter 
You've encouraged me to see what other data is out there. The USGS National Elevation Dataset has data with horizontal resolution of 1/9, 1/3, 1, and 2 arc seconds. The 1/9 set would correspond to about ten feet. Wow!

I am definitely going to have to explore this further. But now I have other things I need to do.
post #11 of 12
Thread Starter 

First of all, the data and my representation are free to use.  The data is public domain, according to the USGS website, and I'm releasing my work (and future versions in this thread) to the public domain too.

 

I searched on the National Map website, which looks a lot like the earthexplorer website, but with different data products.

Turns out there is no 1/9 arcsec data available for Wolf Creek, but there is 1/3 arcsec data.  Unfortunately it is in a different data format, so it may take some fiddling to get it read correctly.  I'm downloading it now.

 

Does anyone know what topo maps are based on?  The apparent resolution seems to exceed the resolution of the underlying data.  I'm guessing there may be a certain amount of "informed guess" used to interpolate.

post #12 of 12
Thread Starter 

I finally got the 1/3 arcsec data from the USGS National Elevation Dataset.

Hard to work with -- it comes in 350 MB tiles, which take several hours per tile to download.

(I grabbed the tile with Snowbird, and probably the rest of LCC and BCC, and will post it later.  I tried for Jackson, but may have grabbed the wrong tile (ugh!).)

 

So here is the high-res Wolf Creek Steep map.  I'll have to admit it looks more like @nathanvg 's data than the 1 arcsec data.

Still some serious steeps in there, though...

 

and the expanded views of waterfall, alberta peak, knife ridge,

Data and my views are public domain.

 

 

 

 

 

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